95 lt1 injector offset questions [Archive]

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Mr.owl

11-11-2018, 01:39 PM

How important is the injector offset adder? Not the voltage offset but the injector offset adder

Terminal_Crazy

11-11-2018, 03:48 PM

How important is the injector offset adder? Not the voltage offset but the injector offset adder

Increasingly as your injector PW goes lower to where it starts affecting the fueling

Really depends on how low your Injector PW Goes...
If you've gor a big set of injectors, the PW is relatively shorter so the amount of misfueling starts to incxrease.
Anything above 1.5mS - 2mS idling is probably tuneable around

I have had injectors that didn't open reliablby below 1.5mS (actually rated at 2mS) which possibly caused issues.

Mitch

sherlock9c1

11-14-2018, 11:45 PM

Any fool can go in and set the flow rate and the motor will run fine above 20% throttle. But if you want idle and part-throttle drivability, and especially if you want it to start quickly and smoothly, you have to have the short pulse adders and voltage offsets correct, respectively.

The way Ford labels and characterizes their injectors is really helpful - they actually have a number called MINPW which is the minimum pulsewidth the injectors will reliably fire. The last time I sized injectors for a friend's build, we were looking hard at injectors that had this data available. For this particular situation we actually discovered that a set of 80lb injectors had a lower MINPW than the 60lb injectors he was considering, even though the 60s would have met the fuel needs of the motor. Given that this was a heavy manual transmission car, I insisted that the injectors be able to reliably fuel down to 400rpm during clutch engagement, and so the 80s would have been the better choice despite their higher peak flow.

Ford also includes two slope values (a high slope and a low slope) and a transition point. This transition point is where the pulsewidth gets so short that the magnetic field delays and the pintle rise/fall times become significant relative to the requested pulsewidth. Here's an example. https://performanceparts.ford.com/parts/ics/m-9593-lu34.pdf It's at this transition point where the GM short pulse adders start to grow. There are some posts out there how to convert the elegant Ford values to the verbose GM values, but the result is perfectly characterized injectors from the first crank.
Personally I'm running 2011-2017 Ford Mustang GT injectors in my LT1 with fabulous drivability.

It continues to blow my mind how places like Racetronix advertise GM injectors with NONE of these critical parameters available. Maybe they have it on their forums, but their rules state you have to buy something before they'll give you forum access. Huh?

hotrodf1

11-26-2018, 07:03 PM

I'll add too - when I swapped to Bosch D III injectors , just 32 lbs, I found that I had to just zero out the pulsewidth adder (not batt. voltage offset), because the Bosch injectors are the other way. I was told they flow more fuel at low PW, and with LT1 you can't take away only add, which is the wrong way. So it depends on which injectors you use as to what all you change in the tune. FIC was absolutely no help on this, even though I bought the injectors through them. They had the data somewhat tailored for the LS1 crowd.

Mr.owl

11-28-2018, 10:19 AM

Mr.owl

11-28-2018, 10:21 AM

Also thank you to everyone for your replies. A lot of helpful information

sherlock9c1

11-28-2018, 02:55 PM

I'm running fic blue demon 36lb injectors had same issue fic was no help. Issue I'd been having was cruise drivability bucking and the afr bouncing a lot. granted I have a pretty big cam. But idle and fire up have been no issue. I'm running sd because I was having issues with maf tuning with my 110 LSA but I've got it pretty close now in sd without changing my adder thanks to trimalyzer. Still think there's more room for improvement there though. But what you're saying is you zeroed yours out? Think I should go back to my base tune zero them out and start over?
Why not give it a shot, and if it doesn't work, go back to what you had.
I don't have experience with this issue, but what came to mind was this thread (http://www.gearhead-efi.com/Fuel-Injection/showthread.php?6260-94-95-EE-xdf-(EEXTRA)&p=72241&viewfull=1#post72241) on here where they delayed the injector start time until after the exhaust valve closed to avoid putting raw fuel into the exhaust. Have you tried that to see if it cleaned up the AFR instability when running in MAF mode?

Mr.owl

12-01-2018, 09:22 AM

Why not give it a shot, and if it doesn't work, go back to what you had.
I don't have experience with this issue, but what came to mind was this thread (http://www.gearhead-efi.com/Fuel-Injection/showthread.php?6260-94-95-EE-xdf-(EEXTRA)&p=72241&viewfull=1#post72241) on here where they delayed the injector start time until after the exhaust valve closed to avoid putting raw fuel into the exhaust. Have you tried that to see if it cleaned up the AFR instability when running in MAF mode?

I have not tried that no. Not sure how I'd go about that on a 95 lt1 but I've had pretty good success switching over to sd in terms of drivability, after much tuning obviously. I am running a wideband as well as my factory o2s and they're reading pretty close so I don't know that raw fuel tainting was so much the issue as much as what happens to readings from the maf with big cams. I also don't have as much experience in tuning maf as I do sd but It was a terrible tune, worst mail order I've ever seen. I might mess with it more in the spring or when weather permits but it's started snowing here already

spfautsch

12-27-2018, 05:41 AM

I ran across this thread a week or so back when I "forked" an EOIT thread to hopefully spark more focused and meaningful discussion on that particular subject.

Anyway, the more I read the more I find in common. I'm also running a set of "recapped" / redrilled inectors from FIC. I asked them for data ahead of the purchase and was promised something would be shipped with the injectors but found no such information included in the shipment and received no further responses from them on the subject. These were sold as 42lb/hr bosch IIIs. Upon opening the package I found a set of 8 GM 12561462 / Bosch 0280155931 grey injectors that likely began life as 28 lb/hr LS1 injectors.

Back to the present - several hours of reading later (most important reading found here (https://eficalibrator.files.wordpress.com/2014/09/whosgettingdrilled.pdf)) I come to a fuller realization that the original injector data is likely all but useless.

So I'm wondering if anyone has any ideas / recommendations on who might be able to properly flow test injectors. Not an injector cleaning shop type test, but a real characterization test that demonstrates slope and offset at different pressures and voltages.

Any fool can go in and set the flow rate and the motor will run fine above 20% throttle. But if you want idle and part-throttle drivability, and especially if you want it to start quickly and smoothly, you have to have the short pulse adders and voltage offsets correct, respectively.

I'm discovering that the slow and painful way. Though I've achieved relatively decent results using the SVO injector offset vs. voltage table, I think more accurate injector data couldn't hurt. After "a lot" of reading on the subject I've come to find that anyone that tests injectors and specs static flow rate should probably not be trusted to provide a truly matched set of injectors. And by matched I mean injectors that share the same flow characteristics at all pulsewidths, pressures and voltages. I believe this is why this particular company generally removes the Bosch part number from the body, and sometimes paints their "matched" injector sets (blue, hence the name "blue demon").

Personally I'm running 2011-2017 Ford Mustang GT injectors in my LT1 with fabulous drivability.

Would you have a part # on those?

sherlock9c1

12-27-2018, 06:28 AM

BR3E-EB-B556V is what I just pulled off the bodies of a set on eBay. I'm not near the car at the moment. Just make sure not to get the 18-19 ones as they're much smaller flow since Ford went to a combo direct AND port injection setup in 2018.

johnny_b

12-27-2018, 07:25 AM

from FIC. I asked them for data ahead of the purchase and was promised something would be shipped with the injectors but found no such information included in the shipment and received no further responses from them on the subject.

Similar experience with FIC. They don’t seem to understand the importance of this data for proper tuning. I will never purchse from them again.

There is a company near me called deatschwerks, they do all types of stuff with pumps, injectors etc.

One of the services they offer is offset testing. I have used them before with positive results

Terminal_Crazy

12-27-2018, 10:35 AM

I'll add a me too to this list

I'm now on my 5th set.
30# venom off ebay seemed ok at the time before I rebuilt the engine.
Since the rebuild I've had a low speed surge I could never get rid off.
Injectors have been swapped bank to bank & end to end with no changes.
suspected injector data as tune had them zeroed out... makes sense if you don't know what they are.

From FIC (Fuel Injection Connection)
30lb Modified Bosch 3 Injectors ( Stainless later core )
No data. still ran the same. excellent other than low speed idle.

42lb @ 3 Bar Modified Bosch Blue Demon 3 Fuel Injectors
No data again still ran the same. excellent other than low speed idle.
Managed to get "some" data that didn't make much sense.

Bought some "Black Ops" off the net. read reviews etc.
Got "some data". Data on sheet doesn't match spec's quite the same & some variance on spray numbers etc.
No real change to the way it ran.
Given up with Black Ops injectors dropping out at low injector Pw..
Min Listed PW is 1.4mS & I'm running idle around 1-1.2 other than that they are OK once rolling.

Bit the bullet and went for "recommended" "quality" injectors from the _other_ FIC (Fuel Injector Clinic)
445cc (50 lbs/hr at OE 58 PSI fuel pressure) FIC Fuel Injector Clinic Injector Set for LT1, LT4 engines (High-Z) (IS300-0445H)
again got data ( off their website). Again didn't quite match the specs on the sheet. again some variance on the flow (They could write anything on the sheet though)
Had to write a program to calc data required. Also flow rate is now a lot lower than it was with the Black Ops.
OK My issue is still there but AFR is a little more stable than it was and is more readable on the guage. ( after trimming the AFR range etc)
I've just raised the low pulse adder and it has richened up the idle quite a bit. ( I just slid the slope along a few points).
Idle is in the 1.7mS time now rather than 1-1.2 with the black Ops so small pulses aren't dumping as much fuel.
Injector EoIT is currently at &63.

Car ran pretty well yesterday on a short run out.
it was generally rich (as i'd raised the low pw adder)
Sounds much smoother, not as lumpy.
seemed to cruise much better when lifting and turning corners.

We'll see once it's dialed in a little better.

I don't think the numbers really matter if the injectors are within running spec. They can be tuned generally to run OK

NON of the five sets (or the stock ones) actually flow anywhere near the "correct flow rate"
That's just a starting point with the voltage figures they all supply.
Get it running close with that then adjust VE tables A LOT.
Then when VE hits 100+ ADJUST & REPEAT A LOT.
When it's lean around the idle and below, try raising the low pw adders if they are around that figure.
If they are rich at idle, lower something else and try adding in some slope to the low pw adders.

That was just going to be a "me too" post.
Mitch

sherlock9c1

12-27-2018, 04:42 PM

This is why Injector Dynamics can get away with charging astronomical prices for injectors. As that PDF indicates, they know what they're doing and how to properly characterize injectors so tuners have a known starting point. What drives me crazy is you KNOW the OEMs need and have that data, and yet the aftermarket is often fumbling around in the dark whenever you ask for anything beyond flow rate. Those mustang injectors I mentioned are $300 a set from Ford racing and you can find them much cheaper used, and the characterization data is in the PDF I posted above. Anyway, rant off. This is why I stick with only injectors with available data, whether from a GM tune file or Ford racing data sheet or similar.

spfautsch

12-27-2018, 06:01 PM

Mitch I'm beginning to think a lot of your difficulties are related to low pulsewidth mismatch and / or inconsistency.

My suggestion to you would be to go here (https://calibratedsuccess.com/media/technical-articles/) and read everything.

Then go here (http://injectordynamics.com/the-library/) and read everything.

I contacted Greg Banish last night to see if he would be willing to do full flow testing and he suggested it's not worth the expense and that I look for a set of LS3 / LS7 injectors and run them at 4 bar.

I'd like to give FIC the benefit of the doubt because as I've mentioned I'm not horribly disappointed with the low flow fueling with these current injectors. But I'm relatively sure we'd all be time + money ahead to leave modified injectors alone unless all we're interested in is accurate PE fueling.

spfautsch

12-27-2018, 07:02 PM

BR3E-EB-B556V

Thanks! Those look to be a drop-in except for the connectors. The only thing I dislike about using the Bosch injectors in place of the fat body Multecs on the LT intake is the need for something to stop them from "falling out" of the fuel rail. On my current injectors I cut stainless lock washers and fit them into the groove above the lower o-ring, but these look like the shoulders are large enough to act as stops.

Edit: nevermind, I just found your other post on these here (http://www.gearhead-efi.com/Fuel-Injection/showthread.php?7586-Injectors&p=72923&viewfull=1#post72923) (datasheet also). I guess that'll give me an excuse to turn some spacers for them on the lathe.

Terminal_Crazy

12-27-2018, 10:42 PM

Hi Scott
After reading your post and a couple of threads, i looked back at few logs.
I don't think it's the injectors.
It's only since I moved the EoIT from &60 to &63

The last 4 or five logs have some really weird shit happening.
fic_12b16 is a warm up into CL
http://www.sand-hill.uk/Terminal_Crazy/CrazyLog/fic_12b16.eedata
http://www.sand-hill.uk/Terminal_Crazy/CrazyLog/fic_12b16/jpg

fic_13a1 is the last run I mentioned in the other post that ran ok ??
http://www.sand-hill.uk/Terminal_Crazy/CrazyLog/fic_13a1.eedata
http://www.sand-hill.uk/Terminal_Crazy/CrazyLog/fic_13a1/jpg

On the warmup log, I've mentioned before about the RHS injector dropping out at about 56-60C

On the drive log, the two Injector PW are all over trhe place. NOT seen that before.

I've always watched the O2's until it warmed up and went CL.
I presumed it was the O2's heating up
I've never really watched the Injector PW.

I'll have to try my stock base tune again.

Yes O2's were both replaced again not long ago.

Mitch

sherlock9c1

12-27-2018, 11:36 PM

Yeah, as long as you don't start a run on these injectors on eBay. I need one more set for a car I recently acquired and am grousing about having to pay $90 shipped for a set when Rousch was selling new takeoffs with 3 miles on them a few years back for $49 shipped.

Wow those injector pulsewidths are wacky! Almost looks like one of the data streams is getting smoothed or something. The cold start one is really wacky. If you have dual exhaust, do the tailpipes smell different?

spfautsch

12-28-2018, 12:24 AM

On the warmup log, I've mentioned before about the RHS injector dropping out at about 56-60C

Are your individual cylinder trims all set to 1 or have you tweaked them?

On the drive log, the two Injector PW are all over trhe place. NOT seen that before.

All I'm saying is you seem to be continuously chasing ghosts and the modded injectors seem like they might be the common thread.

Yeah, as long as you don't start a run on these injectors on eBay. I need one more set for a car I recently acquired and am grousing about having to pay $90 shipped...

Sounds like the run is already on. $90 for 8 sounded like a good deal to me so I grabbed a set this morning that had that part # specified in the main / short description. But in the seller description after the seller specified they came off a 2016, the part # they give seems to be the 2018-19 small injector (JR3E-9F593-AB). So I'm already off on the wrong foot.

Terminal_Crazy

12-28-2018, 12:35 AM

Just done a warmup with a base log.

http://www.sand-hill.uk/Terminal_Crazy/CrazyLog/Fic_445H_2nd_Base_Tune-Warmup.jpg
http://www.sand-hill.uk/Terminal_Crazy/CrazyLog/FIC_445H_2nd_Base_Tune-Warmup.eedata

I altered the bare minimum
12B4C * Injector Flow Rate changed from 24.912 lbs/HR
129D5 * Injector Voltage Offsets changed.
129F5 Injector Offset Adder changed.
129F5 Injector Offset Adder changed.
126d5 Min Injector Pulse changed from 1.40 BPW (0x005C)
126d7 use this value when MIN inj pulse reached changed
12B4E Cylinder Volume changed from 717.25 ml/Cyl
12BEE * VE Table - Primary (400-2000RPM) changed.
12C8A * VE Table - Extended (2000-7000RPM) changed.

Forgot to switch off the MAF
EGR,EAS (AIR pump) AND 1-4 control DTC's Not switched off.

Sounded much louder & rougher idle but only 800rpm
It went CL when Splits 121-133 appeared so of course PW don't match.

Questions
Why do Inj PW start off different in those earlier logs?
I thought OL didn't use the O2's
BLM's under 128 are not remembered

The 2 scalars
126d5 Min Injector Pulse changed from 1.40 BPW (0x005C)
126d7 use this value when MIN inj pulse reached changed

I had them sat at 0.79 which is where these injectors should operate (min Inj switching)
Is this too low ???
This is idling around 2ms. I was around 1.65.
Lowest PW went down to about 1.0...

IF I set it around 1.00 it shouldn't go lower than that and go any leaner than what 1.00 would inject.
ie IF PCM requests 0.8 mS we still get 1.00 worth of fuel ?
Inj Offset Adder table tually starts adding fuel at 1.220 mS now

PCM hardly ever went below 1.00mS as AFAIR even with the Black Ops in.

Mitch

sherlock9c1

12-28-2018, 12:44 AM

I'm sure that's the right part number. I've been watching several of those auctions and the 2018-2019 ones have a white clip around the upper ends of them. Immediately contact the seller if there's any confusion. eBay gives buyers an hour to back out for any reason and you can also cancel if the item is not as advertised.

Terminal_Crazy

12-28-2018, 12:57 AM

Are your individual cylinder trims all set to 1 or have you tweaked them?

No. I've measured the difference in AFR by dropping each cylinder & scaling off one of the centre results.

All I'm saying is you seem to be continuously chasing ghosts and the modded injectors seem like they might be the common thread.

I'm out of ideas.
These are from Fuel Injector Clinic -http://fuelinjectorclinic.com/ls1-ls6/IS301-0445H
... These injectors utilize the latest technology and provide great linearity and short pulse width repeatability.

After several sets, I'm fairly comfident it's not the injectors.

The run is already on. $90 for 8 sounded like a good deal to me so I grabbed a set this morning that had that part # specified in the main / short description. But in the seller description after the seller specified they came off a 2016, the part # they give seems to be the 2018-19 small injector (JR3E-9F593-AB). So I'm already off on the wrong foot.

Don't you just love this hobby :-)

Mtch

kur4o

12-28-2018, 01:03 AM

The only thing I dislike about using the Bosch injectors in place of the fat body Multecs on the LT intake is the need for something to stop them from "falling out" of the fuel rail.

I run in the same issue with 98 ls1 injectors, the remedy was to add a second o-ring in the upper slot. Worked really well.

I resolved the injector problems long time ago. Just grab yourself a good GM ls injectors and read this thread
http://www.gearhead-efi.com/Fuel-Injection/showthread.php?6888-lt1-ee-Injector-tables

I even have an updated version that reads injector voltage for ultra precision.

When I switched over from a crap Accel to stock 98 ls1 all of the surging has gone. So definitely crap injectors do cause surging.

Another thing that I noticed shortly before the crap Accel died completely. When cold they run fine only to turn to crap when warmed up. The AFR was jumping all around with no reason and the engine was untunable.

spfautsch

12-28-2018, 01:32 AM

I'm sure that's the right part number.

It is. I asked the seller to cancel and hope that's the last I hear of it. The seller is clear in the short and long description that they're off a 2016 5.0, but if you zoom in on the second image (https://www.ebay.com/itm/3K-Mile-Used-2016-Ford-Mustang-GT-OEM-Fuel-injectors-BR3E-EB-B556V-2011-2017/312199991264?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649) you can faintly make out JR3E-9F593-AB. That's the smaller 2018 and up injector right?

These can be bought new from a particular large volume retailer for $33 each. That's actually not bad for a new piece. A far cry from $50 for a set of 8 but still...

Mitch is it possible you've got the wrong injector data? Those don't look to be modified injectors so maybe they aren't. You mention the offset adder coming in at 1220 us now. I haven't pulled the specs off their site yet but that seems odd. Most of these newer injectors flow higher in the low pulsewidth slope, which the $EE mask doesn't support so everyone just zeros it out. However, I've never seen mine idle below 1.4ms while it was a 355 / 5.7l.

spfautsch

12-28-2018, 01:46 AM

I run in the same issue with 98 ls1 injectors, the remedy was to add a second o-ring in the upper slot. Worked really well.

This is what I did with my Bosch D3s and it worked well also. I found out from experience the o-rings can slip if you get in a hurry to slap the fuel rails back in and the pressure side isn't seated fully. These are pretty sturdy and there's less chance of fuel spraying everywhere.

13574

I've seen your LS table mods and that's very cool. My concern in this thread is geared more towards modded injectors and inaccurate characterization data.

Terminal_Crazy

12-28-2018, 03:17 AM

Mitch is it possible you've got the wrong injector data? Those don't look to be modified injectors so maybe they aren't. You mention the offset adder coming in at 1220 us now. I haven't pulled the specs off their site yet but that seems odd. Most of these newer injectors flow higher in the low pulsewidth slope, which the $EE mask doesn't support so everyone just zeros it out. However, I've never seen mine idle below 1.4ms while it was a 355 / 5.7l.
No Idea.
The Web page publishes data for them.
Data sheet in the box is slighty different.
And the "Flow matched set aren't all the same value on the sheet. SN on injectors don't match sheet.
Seems to be the norm.

42lb
42.5lb@3bar
44.1 @ 47.psi
Flow rate is now currently set at 38.511 with VE's to match as it was very lean.

I'd HOPE a company publishes correct info but who knows.
I got "data" for the slope.
I had to write software to Interpolate it to get it to fit our tables, the same as the Voltage offsets and fuel pressure vs flow rate.
I had "slid" the table along to add more fuel down low for the last few runs.

That worked somewhat for the Black Ops injectors.
I read on Tuner groups where you dial in 14.7 AFR and that's it.
I feel this is trying to balance on the head of a pin.
Keep going fatter with no change until suddenly it's pig rich 12-13 but nice and stable
or
lean it back a bit & it's 15-17 AFR and erratic.

Mitch

Terminal_Crazy

12-28-2018, 10:21 AM

Does anyone know what the following tables do?

2692 IAC Adder - AC pressure -
OK That one seems obvious.
I was going to zero it out as the AFR guage is on the AC.... Don't want it opening IAC when we go lean right?

20CD ac Low Pressure charge vs table -
What does it do ?
WAS all 255 - Do I zero this out?

20DA ac low charge vs table - and this ?
20E7 ac low charge vs table - and this ?

TIA
Mitch

spfautsch

12-28-2018, 07:58 PM

Those mustang injectors I mentioned are $300 a set from Ford racing and you can find them much cheaper used, and the characterization data is in the PDF I posted above.

These (https://performanceparts.ford.com/part/M-9593-M39) look like a particularly good fit also. Do you know of any reason to shy away from buying the Bosch branded part versus one in Motorcraft packaging? The Bosch branded ones seem to be significantly less expensive.

Flow rate is now currently set at 38.511 with VE's to match as it was very lean.

This statement is somewhat troubling, and sort of the salient point of my concern about the subject. For what you paid for those you should be able to plug a known flow # into the IFC field and be done.

I'm by no means an expert, but I think you should be aiming to have the IFC as close to actual as possible. kur4o suggested this to me a while back and it highlighted a flaw in my tuning methodology that I think you might be practicing also. Anyone with better knowledge please jump in and correct me if wrong, but... If you need more room in your VE table you should be scaling your cylinder volume constant because it's only utilized for speed density calcs. The IFC is used by both speed density and MAF calculations - MAF being a fairly cut and dried one; air mass * target afr = reqired fuel mass, then (required fuel mass / IFC) + offset = base pw.

Conversely, if you wanted to find your IFC without having injector data I would think you'd want to be using MAF in OL and compare your wideband to commanded AFR. However with cam overlap you'll want to avoid doing this at lower airflows because of the effect of reversion. Also, you'd still really need to have an accurate offset vs. voltage table at the very least. I don't think there's a truly objective way to find injector offset in-situ.

I'd HOPE a company publishes correct info but who knows.

I'm a big fan of science. Not such a big fan of hope.

I had "slid" the table along to add more fuel down low for the last few runs.

This is even more troubling - are you saying you were using one of the injector constant tables to try and alter fueling? That will definitely cause the ecu to do weird things. The point I've been trying to get across here is if what I'm reading is correct (and I have no reason to dispute it) the ecu needs dead accurate injector data to characterize the fluid dynamics of the injectors. Without it accurate fuel control goes out the window. Once you have accurate data, tuning should be a lot less difficult.

I'll try to get a look at the published specs and see what the low slope looks like for your latest injectors. It's highly possible you don't need anything in the low pulsewidth adder table and that could be causing you some grief.

In regard to your questions on the AC pressure IAC compensators, I may also be completely wrong here but I'm relatively sure those only apply if the compressor request line is enabled. If the clutch isn't engaged the compressor can't effect engine load. But I would have to defer to someone who understands the disassembly better for confirmation of that theory.

Terminal_Crazy

12-29-2018, 06:34 AM

Appologies to anyone if this thread has gone off topic or been hijacked somewhat.

I have another 2 images of the last start
http://www.sand-hill.uk/Terminal_Crazy/CrazyLog/base_start_1.jpg
http://www.sand-hill.uk/Terminal_Crazy/CrazyLog/base-2.jpg

The 1st shows a really BIG difference in the injector PW on cold startup. about 2mS & 6mS initially.

IF this is SDOL (NO MAF, 11C and car not run for 24 Hrs)... WHY is the injector pulse 3 times bigger on the RHS?
Even if i unplugged 1 bank of injectors surely the PCM should'n't know or care at this point?

I did a quick unplug of the injectors and sprayed switch cleaner on all contacts & got the 2nd log
where both InjPW are very similar.
Just another quirk.

I did get another bunch of odd DTC's bounce on and off like i've mentioned before
43 & 43D - Knock sensors - OK LH bank had no fuel so I get those two.
99 Tach output circuit - switched off - still appeared.
97 VSS 4K pulses circuit fault
They have usually gone away after a brief time, maybe related to the lean issue

O2's don't show anything but they are cold. InjPW is not something I've doggedly watched previously.
I never drive until it's hit 86C anyway.

What I have realised is I'm using a socketed PCM with no known provenance so I've ordered another.
I did resocket the last one I bricked but the Prom programmer socket went tits up after I'd flashed several E side chips and I haven't gone back to it.

Originally Posted by Terminal_Crazy View Post
Flow rate is now currently set at 38.511 with VE's to match as it was very lean.This statement is somewhat troubling, and sort of the salient point of my concern about the subject. For what you paid for those you should be able to plug a known flow # into the IFC field and be done.

I'm by no means an expert, but I think you should be aiming to have the IFC as close to actual as possible. kur4o suggested this to me a while back and it highlighted a flaw in my tuning methodology that I think you might be practicing also. Anyone with better knowledge please jump in and correct me if wrong, but... If you need more room in your VE table you should be scaling your cylinder volume constant because it's only utilized for speed density calcs. The IFC is used by both speed density and MAF calculations - MAF being a fairly cut and dried one; air mass * target afr = reqired fuel mass, then (required fuel mass / IFC) + offset = base pw.

Hi Scott,
Ok whilst I don't entirely disagree and will accept any form of discussion...but...
(Sliding the low PW adder table along was just a recent hack to help dump fuel in.
Excess fuel in the VE is pulled out by the BLM's in CL )

I am tuning Speed Density currently.
The Cylinder size is one faily accurate known value in the calculation.
IF I was _just_ changing injectors, my VE table would be "correct"
IF the Injector data was "accurate" as I read from Greg Banish etc the injectors should swap with the new data with no issues.

The way I see it, I only know the flow rate at 1 point, (OK 5 voltages and 4 pressures) but NOT the slope

These injectors are Significantly leaner at 42# then the BlackOps at 42# and we have no provision to alter the slope Other than changing the VE table.
If the VE maxes out I can change either Flow rate or Cylinder size... I know what the cylinder size is.

Conversely, if you wanted to find your IFC without having injector data I would think you'd want to be using MAF in OL and compare your wideband to commanded AFR. However with cam overlap you'll want to avoid doing this at lower airflows because of the effect of reversion. Also, you'd still really need to have an accurate offset vs. voltage table at the very least. I don't think there's a truly objective way to find injector offset in-situ.

Again, that's presuming
your AFR guage is correct and accurate.
Your MAF table is accurate.
Since my MAF was "ported" by the previous owner I should have no idea how innacurate it could be.
Well I did actually log & calculate it years ago to correct the MAF table.
15 years on, is it still accurate ?

Quote Originally Posted by Terminal_Crazy View Post
I had "slid" the table along to add more fuel down low for the last few runs.This is even more troubling - are you saying you were using one of the injector constant tables to try and alter fueling? That will definitely cause the ecu to do weird things. The point I've been trying to get across here is if what I'm reading is correct (and I have no reason to dispute it) the ecu needs dead accurate injector data to characterize the fluid dynamics of the injectors. Without it accurate fuel control goes out the window. Once you have accurate data, tuning should be a lot less difficult.

Agreed & see above.

I'll try to get a look at the published specs and see what the low slope looks like for your latest injectors. It's highly possible you don't need anything in the low pulsewidth adder table and that could be causing you some grief.

I'd be interested to see what you come up with just for comparison
It goes lean. Increasing the VE is OK in OL, a fat AFR down to 13.5 ish is stable. CL just pulls it back out

In regard to your questions on the AC pressure IAC compensators, I may also be completely wrong here but I'm relatively sure those only apply if the compressor request line is enabled. If the clutch isn't engaged the compressor can't effect engine load. But I would have to defer to someone who understands the disassembly better for confirmation of that theory.
Aha, I hadn't thought of that. Excellent.

Thanks
Mitch

(Think I'll go back to bed, it's half three in the morning. )

spfautsch

12-29-2018, 06:04 PM

I also hijacked this thread, but honestly I think your issue may not be too off topic.

I did get another bunch of odd DTC's bounce on and off like i've mentioned before
43 & 43D - Knock sensors - OK LH bank had no fuel so I get those two.
99 Tach output circuit - switched off - still appeared.
97 VSS 4K pulses circuit fault
They have usually gone away after a brief time, maybe related to the lean issue

O2's don't show anything but they are cold. InjPW is not something I've doggedly watched previously.
I never drive until it's hit 86C anyway.

What I have realised is I'm using a socketed PCM with no known provenance so I've ordered another.

Do you mean another PCM?

Have you double checked all your PCM grounds?

I did look briefly at the data FIC(linic) had for the 445cc injectors. That's what you're running currently, right? Anyway, it was all but meaningless to me b/c all the tables were expanded to use MAP. I'm interested in how you interpolated the data for the $EE tables. I know dzidaV8 has some excel stuff floating around but I'd prefer not to have to use M$ Excel if possible.

These injectors are Significantly leaner at 42# then the BlackOps at 42# and we have no provision to alter the slope Other than changing the VE table.

No offense but that seems like backwards thinking. If you have injectors that were supposed to be 42 lb/hr and they're running leaner than another set (assuming your VE stayed the same) there are three primary things that could be wrong. Those are IFC / high slope, low pulse adders / low slope, and offset.

It does sound like you may have other weirdness going on there, as well as a lot of other variables. I didn't know your MAF had been messed with. You mentioned that you forgot to turn off the MAF in your initial "back to starting point" tune earlier. I trust you fixed that and you're still getting the odd behavior with PWs all over the place?

Do you still have your factory Multecs? I'm seriously debating putting mine back in for first fire.

kur4o

12-29-2018, 06:28 PM

The 1st shows a really BIG difference in the injector PW on cold startup. about 2mS & 6mS initially.

I noticed you are using some beta version 4.8 of eehack.

Where did you get it. Last stable release was 4.7 , and I used 4.7 as a base for all mods I have done.
It could be that this beta version has some bugs in the datastream.

I suggest you to switch to 4.7 or the one I modified and try to duplicate that condition. It is weird because narrowband 02s are the same accross the banks and did not get lean, on the right side with that much fuel you should get a stall at cold start up.

I suspect a bad injector on the right side also, you got intermitten lean conditions on the right side which resembles me the same conditions I got with an injector set that went in the trash bin.

That random errors also suggest a bad wiring or bad pcm. You should check for melted wires around headers.

On another note, Why don`t you get a 85mm truck MAF and give it a try. It is not that expensive and will support a lot more airflow. Delphi units goes for 70-80$.

Terminal_Crazy

12-30-2018, 04:21 PM

HI

Do you mean another PCM?
Yes, I don't have a spare atm.

The only other thread I've read about surging not going away, the poster changed their cam.

Have you double checked all your PCM grounds?
Not yet but after cleaning/reseating the injectors I'll check all grounds & PCM connections as well.

all the tables were expanded to use MAP. I'm interested in how you interpolated the data for the $EE tables.
The Online Data doesn't mach up with the supplied data[/QUOTE]

I originally emailed FIClinic:
Which kPa value i would use for an LT1 with the 16188051
OBD1 PCM for the Voltage offsets.
The fuel system is the std 3 bar with the referenced FPR. So I'm thinking I
would use 300kPa vaules from the table

Response was: 300kpa values should work fine.

Data supplied: I'll scan data sheet if anyone is interested.
Slope flow matching data: Average flow rate at 43.5psi = 428cc/min. Your set is Flow matched within 1.9%
Injector offset matching data: Average offset at 3bar & 13.5V 962uS. You set is matched within 1.4%

In my notes Fuel pressure at Idle with Vac hose off is 47psi (which is what the engine should see under WOT)

**** So we need to use the 47psi injector kPa value ===
1 psi = 6.89476 kPa
47 psi = 324.05372 kPa

LS table Spacing is spaced 16.0kPa which is approx 2.3206038037 psi

I don't use MS Excell but I do use Libre Office Calc and none that I have are able to Interpolate data...
So I wrote a program to do a linear interpolation (don't ask about slope matching) to generate some nos.

This gives Interpolated results of
Volts Kpa From Next table
0.000000 324.050000
========================
0.400000 291.645000
0.800000 259.240000
1.200000 226.835000
1.600000 194.430000
2.000000 162.025000
2.400000 129.620000
2.800000 97.215000
3.200000 64.810000
3.600000 32.405000
4.000000 0.000000
4.100000 0.000000
4.200000 0.000000
4.300000 0.000000
4.400000 0.000000
4.500000 0.000000
4.600000 0.000000
4.700000 0.000000
4.800000 0.000000
4.900000 0.000000
5.000000 0.000000
5.100000 0.164857
5.200000 0.329714
5.300000 0.494571
5.400000 0.659428
5.500000 0.824285
5.600000 0.989142
5.700000 1.153999
5.800000 1.318856
5.900000 1.483713
6.000000 1.648570
6.100000 1.643023
6.200000 1.637475
6.300000 1.631928
6.400000 1.626380
6.500000 1.620833
6.600000 1.615285
6.700000 1.609738
6.800000 1.604190
6.900000 1.598643
7.000000 1.593095
7.100000 1.584205
7.200000 1.575315
7.300000 1.566424
7.400000 1.557534
7.500000 1.548644
7.600000 1.539754
7.700000 1.530863
7.800000 1.521973
7.900000 1.513083
8.000000 1.504192 2.100000
8.100000 1.492807
8.200000 1.481421
8.300000 1.470035
8.400000 1.458649 1.967172
8.500000 1.447263
8.600000 1.435877
8.700000 1.424491
8.800000 1.413106 1.834345
8.900000 1.401720
9.000000 1.390334
9.100000 1.377277
9.200000 1.364220 1.701517
9.300000 1.351163
9.400000 1.338107
9.500000 1.325050
9.600000 1.311993 1.568690
9.700000 1.298936
9.800000 1.285880
9.900000 1.272823
10.000000 1.259766 1.435862
10.100000 1.245878
10.200000 1.231990
10.300000 1.218102
10.400000 1.204214 1.363448
10.500000 1.190326
10.600000 1.176438
10.700000 1.162550
10.800000 1.148662 1.291034
10.900000 1.134774
11.000000 1.120887
11.100000 1.106987
11.200000 1.093088 1.218621
11.300000 1.079189
11.400000 1.065289
11.500000 1.051390
11.600000 1.037490 1.146207
11.700000 1.023591
11.800000 1.009692
11.900000 0.995792
12.000000 0.981893 1.073793
12.100000 0.968827
12.200000 0.955761
12.300000 0.942695
12.400000 0.929629 1.024345
12.500000 0.916563
12.600000 0.903497
12.700000 0.890431
12.800000 0.877365 0.974897
12.900000 0.864299
13.000000 0.851232
13.100000 0.839822
13.200000 0.828411 0.925448
13.300000 0.817001
13.400000 0.805590
13.500000 0.794180
13.600000 0.782769 0.876000
13.700000 0.771359
13.800000 0.759948
13.900000 0.748538
14.000000 0.737127 0.826552
14.100000 0.728220
14.200000 0.719312
14.300000 0.710404
14.400000 0.701496 0.793103
14.500000 0.692588
14.600000 0.683680
14.700000 0.674773
14.800000 0.665865 0.759655
14.900000 0.656957
15.000000 0.648049 0.742931
15.100000 0.642464
15.200000 0.636878
15.300000 0.631293
15.400000 0.625708
15.500000 0.620123
15.600000 0.614537
15.700000 0.608952
15.800000 0.603367
15.900000 0.597781
16.000000 0.592196 0.659310
16.100000 0.590775
16.200000 0.589355
16.300000 0.587934
16.400000 0.586513
16.500000 0.585093
16.600000 0.583672
16.700000 0.582252
16.800000 0.580831
16.900000 0.579410
17.000000 0.577990
17.100000 0.577990
17.200000 0.577990
17.300000 0.577990
17.400000 0.577990
17.500000 0.577990
17.600000 0.577990
17.700000 0.577990
17.800000 0.577990
17.900000 0.577990
18.000000 0.577990
18.100000 0.577990
18.200000 0.577990
18.300000 0.577990
18.400000 0.577990
18.500000 0.577990
18.600000 0.577990
18.700000 0.577990
18.800000 0.577990
18.900000 0.577990
19.000000 0.577990
19.100000 0.577990
19.200000 0.577990
19.300000 0.577990
19.400000 0.577990
19.500000 0.577990
19.600000 0.577990
19.700000 0.577990
19.800000 0.577990
19.900000 0.577990
20.000000 0.577990

Figures supplied & Interpolated were
Volts PSI
0.000000 47.000000
=================================
0.400000 44.755000
0.800000 42.510000
1.200000 40.265000
1.600000 38.020000
2.000000 35.775000
2.400000 33.530000
2.800000 31.285000
3.200000 29.040000
3.600000 26.795000
4.000000 24.550000
4.400000 22.305000
4.800000 20.060000
5.200000 17.815000
5.600000 15.570000
6.000000 13.325000
6.400000 11.080000
6.800000 8.835000
7.200000 6.590000
7.600000 4.345000
8.000000 2.100000
8.100000 2.066793
8.200000 2.033586
8.300000 2.000379
8.400000 1.967172
8.500000 1.933966
8.600000 1.900759
8.700000 1.867552
8.800000 1.834345
8.900000 1.801138
9.000000 1.767931
9.100000 1.734724
9.200000 1.701517
9.300000 1.668310
9.400000 1.635103
9.500000 1.601897
9.600000 1.568690
9.700000 1.535483
9.800000 1.502276
9.900000 1.469069
10.000000 1.435862
10.100000 1.417759
10.200000 1.399655
10.300000 1.381552
10.400000 1.363448
10.500000 1.345345
10.600000 1.327241
10.700000 1.309138
10.800000 1.291034
10.900000 1.272931
11.000000 1.254828
11.100000 1.236724
11.200000 1.218621
11.300000 1.200517
11.400000 1.182414
11.500000 1.164310
11.600000 1.146207
11.700000 1.128103
11.800000 1.110000
11.900000 1.091897
12.000000 1.073793
12.100000 1.061431
12.200000 1.049069
12.300000 1.036707
12.400000 1.024345
12.500000 1.011983
12.600000 0.999621
12.700000 0.987259
12.800000 0.974897
12.900000 0.962534
13.000000 0.950172
13.100000 0.937810
13.200000 0.925448
13.300000 0.913086
13.400000 0.900724
13.500000 0.888362
13.600000 0.876000
13.700000 0.863638
13.800000 0.851276
13.900000 0.838914
14.000000 0.826552
14.100000 0.818190
14.200000 0.809828
14.300000 0.801466
14.400000 0.793103
14.500000 0.784741
14.600000 0.776379
14.700000 0.768017
14.800000 0.759655
14.900000 0.751293
15.000000 0.742931
15.100000 0.734569
15.200000 0.726207
15.300000 0.717845
15.400000 0.709483
15.500000 0.701121
15.600000 0.692759
15.700000 0.684397
15.800000 0.676034
15.900000 0.667672
16.000000 0.659310

Accurate choice of two there !

FIC Inj Short Pulse adder
Mix of two PCM tables

Inj Pulse adder
0.0 0.250 0.0 0.250
0.06 0.236
0.1 0.227
0.12 0.222
0.18 0.209
0.24 0.195
0.30 0.181 0.3 0.182
0.36 0.167
0.4 0.159
0.43 0.153
0.49 0.139
0.5 0.136
0.55 0.126
0.6 0.114
0.61 0.112
0.67 0.098
0.73 0.084
0.79 0.029
0.8 0.068
0.85 0.057
0.9 0.045
0.91 0.043
0.97 0.029
1.0 0.023
1.03 0.015
1.09 0.001
1.1 0.0
1.16 0.0

Interpolated data (LT1 table min division is 15.3uS)
====================
488=139.2 == 137.2 0x09
549=126.2 == 122.1 0x08
610=112.0 == 106.8 0x07
671= 97.5 == 91.6 0x06
732= 81.2 == 76.3 0x05 *
793= 69.3 == 76.3 0x05 *
854= 56.0 == 61.0 0x04
915= 41.6 == 45.8 0x03
976= 27.6 == 30.5 0x02
1037= 13.1 == 15.3 0x01
1098= 1.0 == 0.0 0x00

The 1st shows a really BIG difference in the injector PW on cold startup. about 2mS & 6mS initially. I noticed you are using some beta version 4.8 of eehack.

Where did you get it. Last stable release was 4.7 , and I used 4.7 as a base for all mods I have done.
It could be that this beta version has some bugs in the datastream.

I suggest you to switch to 4.7 or the one I modified and try to duplicate that condition. It is weird because narrowband 02s are the same accross the banks and did not get lean, on the right side with that much fuel you should get a stall at cold start up.

The 4.8 I think was from Steveo's site. This is on the PC in my office. The car is either running 4.7 or your 13_10_2018_v2 version.

I suspect a bad injector on the right side also, you got intermitten lean conditions on the right side which resembles me the same conditions I got with an injector set that went in the trash bin.

That random errors also suggest a bad wiring or bad pcm. You should check for melted wires around headers.

If you look again, in the 2nd jpg, both injectors are around 5 or 6mS.
This is on a bog stock Z28 tune.
The fault seemed to be on the LHS

A new PCM is on its way.

What I find strange is that
a: the O2's don't suggest anything odd but then they are still cold.
b: How or WHY is the Injector pulse calculated differently for each bank ?

I replugged/sprayed cleaner on the injector connectors between runs.

On another note, Why don`t you get a 85mm truck MAF and give it a try. It is not that expensive and will support a lot more airflow. Delphi units goes for 70-80$.

I never got that far with the tuning :-)
I started tuning SD and this lean surge has never fully gone away unless I dump fuel into it.

Mitch

spfautsch

12-30-2018, 06:43 PM

Slope flow matching data: Average flow rate at 43.5psi = 428cc/min. Your set is Flow matched within 1.9%
Injector offset matching data: Average offset at 3bar & 13.5V 962uS. You set is matched within 1.4%

In my notes Fuel pressure at Idle with Vac hose off is 47psi (which is what the engine should see under WOT)

**** So we need to use the 47psi injector kPa value ===
1 psi = 6.89476 kPa
47 psi = 324.05372 kPa

The fact that they gave you a specific offset and static slope is promising.

Unless you have an adjustable FPR I think I'd regenerate your data using 43.5 / 300kpa unless you have an overwhelming amount of faith in the accuracy of the gauge that 47psi was measured with. If it's a typical shop grade gauge that registers 0-100, a 3-5 psi indicator error along with a 3-5% linearity error is not unheard of. Here in the states we have the "miracle" of Harbor Freight which is a huge importer for extremely low grade instruments such as the one I purchased. Mine would read 46 psi on my 4 bar vehicles. Most troubleshooting guides will tell you a 4 bar system won't even start at 46 psi. I replaced the original junk gauge with a $20 liquid filled gauge from the hardware store and it reads in the relative neighborhood. But I still wouldn't use it as a calibration reference.

I was more interested in the method you used for interpolation than the data. I'd really like to develop something that works in libreoffice. But that would probably be info better suited for a different thread.

Good luck...

Edit: Another simple check I would suggest is measuring your injector impedances from the PCM connector while having a helper jostle the harness around. This would tell you if all the injector leads in your harness are intact.

Terminal_Crazy

12-30-2018, 09:25 PM

Hiya

Quick update. I still have some weird shit going on...

OK I've spent the afternoon recalculating the Offsets
I recalculated IFC at 44.1 (47psi) which should be very lean from 38.51 (about 14%))

I see what you save above, so can still pull it back to 42 later.

I used the data of the website to recalc the Voltage Offsets.
At 13.6V the difference is about 11.5% lower
Reset the Low PW adder table

I Flashed with Kur4o's 13_10_2018 EEHack 4.90
I Have NOT altered the in car laptop to view the InjectorPW so didn't see the same issue as befor until I got the log up on my desktop.

First start, by 86C had idle BLM's at 138 154 - not too shabby
as it got hotter BLM's moved.
141 154
143 154
144 154
146 147
148 148 OK
went for short drive RH BLM 16 topped out at 160
Trimalyzed data which really increased the low map areas up & went out again.

Car ran OK and was generally happy
Surge was still present but car did idle at 7mph quite happily.
Surge came on as soon as increased throttle 1.2% and went off after about 15mph (8%tps)

I might pick up some O2 sensors and replace them as well as checking all the grounds and cables etc.

I still don't KNOW why the InjPW would be different in Open Loop ?

Interpolation of data:
I don't use MS Excel and my use of LibreOfficeCalc is limited
I don't think interpolation is available as std. There seemed to be some extension available for Excel.
The maths to fit curved data was well outside my field.
I started to read an glazed over.
So my program just uses linear interpolation.
For day to day use I have ARM processor based computers as well as PC's and Linux boxes.
My main computer runs RISCOS, written by Acorn from the original BBC micro back in the 80's who then went on to develop the ARM processor.
For quick calculations I either use BBC Basic an easy & fast programming language or write programs in C/C++

Anyways. for the interpolation, I take a data table such as
0 5
10 100
decide how many points I want (say 5 across the columns and 5 between the rows )
Precalculate the size of grid needed to fit the data in so i end up with
0 x x x x 5
x x x x x x
x x x x x x
x x x x x x
x x x x x x
10 x x x x 100

Then move across the cells. Dividing the difference up as a fraction of the difference (5-0 =5. 5/5==1 ) so we get 0+1x1, 0+2x1, 0+3x1, 0+4x1, until we hit the next row
I then calculate the next data row 10 to 100 so that is (100-10=90. 90/5 == 18 ) so we get 10+1x18, 10+2x18, 10+3x18, 10+4x18
this gives me
0.000000 1.000000 2.000000 3.000000 4.000000 5.000000
x x x x x x
x x x x x x
x x x x x x
x x x x x x
10.000000 28.000000 46.000000 64.000000 82.000000 100.00000

Then traverse the grid for each column which gives us
0.000000 1.000000 2.000000 3.000000 4.000000 5.000000
2.000000 6.400000 10.800000 15.200000 19.600000 24.000000
4.000000 11.800000 19.600000 27.400000 35.200000 43.000000
6.000000 17.200000 28.400000 39.600000 50.800000 62.000000
8.000000 22.600000 37.200000 51.800000 66.400000 81.000000
10.000000 28.000000 46.000000 64.000000 82.000000 100.000000

IF you can explain how to calculate this any better to fit curved tables i'd be interested.
As it is, each grid virtex (4 points) are plotted linearly onto a plane.

Mitch

kur4o

12-31-2018, 12:26 AM

I see you are out of ideas, so why don`t you jump in and give it a try of the ls injector patch. Anyway you already have the needed cal data.

When I put the ls injectors I figured that is not possible to interpolate the tables good enough, and since ls injector data is superior to anything gm have done previously I just made the patch to utilize the improved ls inj data.

The PCM calculates how much air enters the engine in grams/second. Than slash that to the commanded AFR and find the needed fuel in grams/second.

The grams of fuel needed are converted to inj pulse width with the help of engine rpm and fuel flow constant.

So you need a dead spot fuel flow constant. It should be 43.5psi /3 bar at WOT, if it is other than that check your regulator or gauge.

Than the PCM adjust the voltage offset. At lower voltage the injector don`t open fast enough and the pcm compensate for the less fuel flow by adding some ms to already calculated inj pulse width.

Unfortunatelly the fuel flow of the injectors is not linear from zero. It gets linear after about 3-4ms range. Below that range they flow less in most cases and the PCM compensate by adding more ms to inj pulse width. The curve here is what matters most.

If any of this components are not accurate you will get all kind of weird conditions running lean and rich at the same time under different engine loads that require the same pulse width.

Tuning at this point is not possible.

Tuning air tables through injector constants is really bad idea that should be avoided on all costs.

Ve table should be smooth and linear accross the table. The ve value is interpolated almost anytime between 4 adjacent cells and you can jump from lean to rich really easy if the transition is not smooth enough. Maf is much easier to tune so you can give it a try. You should always tune VE and MAF at open loop until you match the commanded and the actual afr.

At this point I can only suggest to start from scratch and do it all over again the right way. Tune everything in open loop and than switch to closed loop.

On the right side I saw 02s drop to zero on several occasions with no apparant reason, suggesting bad injector.
Don`t focus that much on inj pulse width, 02s give better idea what`s happening.

I hope you can duplicate that inj difference at start up. In open loop the two sides must have almost identical readings. Some fluctuations are possible due to the data stream updates at different times accross banks.

Terminal_Crazy

12-31-2018, 02:36 AM

On the right side I saw 02s drop to zero on several occasions with no apparant reason, suggesting bad injector.
Don`t focus that much on inj pulse width, 02s give better idea what`s happening.

I hope you can duplicate that inj difference at start up. In open loop the two sides must have almost identical readings. Some fluctuations are possible due to the data stream updates at different times accross banks.

I need to sort out this weird issue first.
I hadn't seen the InjPW go to zero but when they match up they are much less stable than the lhs in the offset display.
This seems to have started about 12 DEC and when I started playing with the EOIT so i'll try an earlier bin again that was ok.

It's in about 7 of the last 14 logs. I need to adjust EEhack graph so it displays the PW taller

Strange thing is, the car sounds and runs ok.

Thanks for the input.
Mitch

spfautsch

12-31-2018, 08:29 AM

OK I've spent the afternoon recalculating the Offsets
I recalculated IFC at 44.1 (47psi) which should be very lean from 38.51 (about 14%))

Once again, why are you using 47 psi to calculate flow? Do you have an adjustable fuel pressure regulator?

Terminal_Crazy

01-02-2019, 03:04 PM

Once again, why are you using 47 psi to calculate flow? Do you have an adjustable fuel pressure regulator?
That was measured fuel pressure.
I recalculated the voltage offsets with the online generic data rather than off the supplied sheet.
Change from previous data was about 10-14% lower. IFR raised back to rated 42# an increase of about 14%
I then recalculated offsets back at the 300kpa pressure and there were minor differences.

Reflashed with EEHack 4.7
Initial fire up was a bit rich, blm’s sat about 151-121 so I resloped the VE Tables.
This change has brought the low corner of the VE table up quite a bit and doesn’t drop off like a ski slope now.
Blm sat at 126-127.
Needs a run out now.

New pcm and o2’s are on their way.
Issue withe InjPW seems to have gone so maybe just a wierd flash issue.

Mitch

kur4o

01-03-2019, 01:46 AM

I got a little confused what you are trying to do.

First you need that fuel flow figured. If you have the fuel flow at 42 pounds at 4 bar, you need to convert it to 3 bar flow.

The formula is x*0.86602540378
x= fuel flow at zero vacuum at 4 bar fuel pressure, [zero vacuum value should be the lowest value in the ls data].

Than you have to convert the voltage offset. You should have a ls data table called injector offset vs vacuum vs volts . Take again the row at zero vacuum and interpolate to lt1 voltage . It will take some time but it can be done by hand easily.

spfautsch

01-03-2019, 04:52 AM

That was measured fuel pressure.

With a factory pressure regulator?

sherlock9c1

01-04-2019, 08:14 PM

For what it's worth, on every older LT1 I've measured, the fuel pressure has always been on the high side, usually 3-4psi higher than spec.

spfautsch

01-08-2019, 06:58 AM

For what it's worth, I doubt you (or, more specifically Terminal_Crazy) was / were measuring with a recently calibrated, laboratory grade instrument. One can easily spend $300-$400 on such a device and it may still be off 1-3 psi "out of the box".

My point is that I'm not sure I would skew all my injector data based on measurements taken with a $20-$50 instrument. And bear in mind a fuel injector "test kit" that sells for $50 likely includes a gauge that's worth about $5 and cost about $2. Just my $0.02, for what it's worth (considerably less than $0.02).

Terminal_Crazy

01-09-2019, 11:20 PM

Hi all.
A little update & reply to you all.

kur4o
I got a little confused what you are trying to do.

First you need that fuel flow figured. If you have the fuel flow at 42 pounds at 4 bar, you need to convert it to 3 bar flow.

The formula is x*0.86602540378
x= fuel flow at zero vacuum at 4 bar fuel pressure, [zero vacuum value should be the lowest value in the ls data].

Than you have to convert the voltage offset. You should have a ls data table called injector offset vs vacuum vs volts .
Take again the row at zero vacuum and interpolate to lt1 voltage . It will take some time but it can be done by hand easily.

The injectors are rated 42lb at 3 bar (50 at 4 bar).
I understood we used the fuel pressure (which is measured from above atomspheric).
So I had _measured_ fuel pressure at 47psi and used the 324.05kPa figures accordingly, not 300kPa (3bar) like I have now, see below.

spfautsch
that was measured fuel pressure.With a factory pressure regulator?

All measurements are slightly more accurate guesses, gotta start somewhere.

sherlock9c1
For what it's worth, on every older LT1 I've measured, the fuel pressure has always been on the high side, usually 3-4psi higher than spec.

spfautsch
For what it's worth, I doubt you (or, more specifically Terminal_Crazy) was / were measuring with a recently calibrated, laboratory grade instrument.
One can easily spend $300-$400 on such a device and it may still be off 1-3 psi "out of the box".

My point is that I'm not sure I would skew all my injector data based on measurements taken with a $20-$50 instrument.
And bear in mind a fuel injector "test kit" that sells for $50 likely includes a gauge that's worth about $5 and cost about $2.
Just my $0.02, for what it's worth (considerably less than $0.02).

Whilst I don't disagree with you, Not measuring it is no less a guess.
The 47psi value converted to 324.053kPa
I interpolated & used the data from 324.05_ so already ANY data is skewed.
Enough to make a difference... unlikely.

....
Anyway
I reset the IFR to the rated 42lb
Recalculated the Voltage Offsets to the 300kPa figure
again Nothing quite matches the same with the generic data or the supplied data
The values were slightly lower ( 1 maybe 2 hex values in each cell).
NOTE: I suspect the VE table has a finer adjustment than the Voltage offsets themselves.

By the time i'd dicked about with the VE table I'm pretty much back where I was before.

I spent the weekend jacking tables around, anything air flow/mass related.
The BLM's & VE were extremely rich
I had the car running real nice, no surge BUT the O2's were averaging 500mV and the car stunk of fuel.
Idle AFR was showing 14.5-15.5 and the fuel guage was moving faster than I was.

I pulled the O2 thresholds to get the O2's averaging 450mV and sloped the VE Tables and voila, I'm back where I was again.

I think I'll tidy the VE tables back up and try with the MAF.
I also have another PCM (1995) rather than a 1997. Doubt that should be an issue?
And some fresh O2 sensors.

Mitch

kur4o

01-10-2019, 12:08 AM

I just want to make sure you are scaling the fuel flow correctly, since you talked about some interpolation.

The forumla is {√new/old pressure}*old flow = new flow
or divide new pressure by old pressure; square root the result. Than multiply with the old flow.

As you can see 50lb/h at 4 bar are 43.3lb/h at 3 bar. So tha data might be wrong or the conversion.
You need to find out at what pressure it is measured. The fluid used for measuring is also a big factor, some use n-heptane and steveo suggest a compensation factor of 1.035 if measured of n-heptane.

Here is some intersting debate over fluids and equipment used for measuring and what effects they have.
One guy noticed that 1degree celsius difference, changed the flow over 5%.

https://www.eng-tips.com/viewthread.cfm?qid=117108

spfautsch

01-10-2019, 12:35 AM

I pulled the O2 thresholds to get the O2's averaging 450mV and sloped the VE Tables and voila, I'm back where I was again.

Does this mean you're back to seeing the weird differences in the injector pulsewidth from bank to bank? Or are you just saying the surge returned?

What is your method for tuning VE, and how confident are you that your table is "close". It took me months to gather enough data with narrowbands to get mine to a point I felt good about it.

Terminal_Crazy

01-10-2019, 01:45 AM

Hi
Datasheet:TestFluid 16B @ 88-91F/32C
Average Flow Rate @43.5psi = 428cc/min.
432, 430, 430, 429, 427, 424, 425, 426

428cc == 40.8Lb/hr Lower again!

Fluid=16B ?? Dunno what that is atm.

40.8 * 1.035 == 42.228 lb (I'm at 41.997)

I'll try 42.228 ( saves as 42.230) I've 44.09, 42.385, 40.8

I have just looked back at the previous log to see if the InjPW dropped low.
Only on decel does it drop below 1.1 and only on slamming the throttle closed.

What i can see now I've increased the scale in EEHack is some oscillation in the PW at low load.
It's crossing map & rpm boundaries but could be the VE table not settled yet
WB is 15.5 to 16.5

I tried slowing down the O2 feedback recently but ended up with a slow rolling idle
I'll have a play with those next.

Thanks
Mitch

kur4o

01-10-2019, 02:11 AM

All the fuel injection companies use 2 types of calibration fluids. For regular production work the Rock Valley Viscor 16A and 16B are regularly used (there are other suppliers as well) for safety reasons. However, the viscosity and density are not the best match to "gasoline" and thus flow ocorrection factors must be used if absolute accuracy is required. For more accurate work, you need an explosion proof test rig and either n-Heptane or Indolene. N-Heptane can be filtered and reused because it is a pure substance. Indolene is your best match to "gasoline" but because it is a blend it can only be used for a single pass and then discarded.

I found this formula
One cubic centimeter per minute converted into pound per hour - Gasoline equals = 0.098 lb/hr
1 cm3/min = 0.098 lb/hr
or 428*0.098 = 41.944

The correction factor of 16b fluid is not known so you may make a research.
1.035 scalar is for N-heptan which is not applicable to you, since the injectors are tested with 16B fluid.

is some oscillation in the PW at low load

If the spread between the cells[on both rpm and map vectors] is not optimal and polished it can result in constant oscillations back and forth.
The best practice is to keep constant rpm and map 2000 and 40 for example and tune with wideband.
Very hard to achieve on the road though. If you can access a load dyno you will be done real quick.

Terminal_Crazy

01-10-2019, 02:30 AM

Cheers for the help. Much appreciated.

Thanks
mitch

spfautsch

01-10-2019, 06:32 AM

If you can access a load dyno you will be done real quick.

This is one of the statements in the Banish tuning "how-tos" I've read recently that I took slight issue with. While I completely agree with the science behind the statement, if we all had a water brake or eddy current dyno in our back pocket, well we'd also be farting cotton candy mixed with unicorn feathers. Dyno time is expensive.

The only substitute I can imagine is finding a road with very intense hills and driving it repeatedly in as many different RPM bands as possible with the cruise control set [edit] and hope you don't encounter traffic.

johnny_b

01-10-2019, 07:22 AM

If the spread between the cells[on both rpm and map vectors] is not optimal and polished it can result in constant oscillations back and forth.
The best practice is to keep constant rpm and map 2000 and 40 for example and tune with wideband.
Very hard to achieve on the road though.

The same can be said about tuning the VE table.

From a controls and numerical methods perspective, once you achieve a converging amount of oscillation variance for changing your VE table, you could then apply the same method to tuning PW vs. Load table until converging amounts of oscillation variance is achieved in the data. this would in theory be the optimal setting

Casey96SS

02-10-2019, 12:17 AM

Hey guys a lot of interesting info in this thread and the seperate EOIT thread. I have learned a lot and got my setup running fairly decent in 2017. Got it a little closer last year. It's pretty good during WOT and cruising but I still think the idle, low RPM surge, and throttle response could use some improvement. Currently running in SD with PE mode enabled at idle. I do have a wideband installed.

I am running modified Bosch III 30-lb injectors from FIConnection. The only data they sent me was offset vs batt voltage.

I think I am just going to start over with the tune in 2019. I would like to accomplish the following things:

1. Fix the VE tables so the are not maxed out on the upper end.
2. Further stabilze the idle and reduce fuel smell. PE mode did help with this. Wondering if adjusting the EOIT will eventually help with this?
3. Reduce mild low RPM bucking.
4. Further improve throttle response.

I figured all of my low RPM and idle issues were because of my cam. Now, after reading about inaccurate injector data and EOIT I am wondering if it could be one of these things?

Would it be worth starting over with the Ford BR3E-EB-B556V injectors since the have published data for them? Thanks for any input!

Stroked 388

02-10-2019, 01:01 AM

sherlock9c1

02-10-2019, 04:18 AM

I would. Keep an eye on eBay or local Craigslist for a low mileage set. If you need help translating the injector data to GM LT1 format, send me a PM. Remember you'll need harness adapters (cheap on eBay). And #205 o rings on the bottom to keep them in the fuel rail (I use PTFE).

Casey96SS

02-10-2019, 11:16 PM

You never got any other data on the injectors ? I would definitely make sure that you have the correct data put in for them. As for EIOT when I tested it out on eehack it blew my mind on how much it changed my fueling for the common big cam problems mind you I've only tested it at idel because of it being winter here. Now my ve tables needs a major re maping. I have a pretty moded LT1 and so far so good. But have more to do to get it perfect. And I just want to throw a thank you out to Ivan and Steve for all there help and the awesome programs they have made to make life of tuning easier. :rockon:

Unfortunately no other data. It took mulitple emails to get what I got. Definitely looking forward to seeing what we are able to learn from EIOT when the weather gets better and more people are able to play around with it. Still snowing in IL!

I would. Keep an eye on eBay or local Craigslist for a low mileage set. If you need help translating the injector data to GM LT1 format, send me a PM. Remember you'll need harness adapters (cheap on eBay). And #205 o rings on the bottom to keep them in the fuel rail (I use PTFE).

Thanks saw the info in your other posts. Will probably pick up a set and try them out. Can't remember what I paid for the FIC ones but the Ford ones would be way cheaper and have accurate data for them. Will definitely PM you if I get my hands on a set!

Stroked 388

02-10-2019, 11:48 PM

I live in IL. What part of IL. Do you live in

Casey96SS

02-11-2019, 12:18 AM

I live in IL. What part of IL. Do you live in

I live in Utica, about 1.5 hours SW of Chicago out in the corn fields. What part are you from??

Stroked 388

02-11-2019, 12:48 AM

I live in South Beloit north Central part on the boarder of Wisconsin that about a 1 hr 45min from Chicago

Casey96SS

02-11-2019, 02:10 AM

I live in South Beloit north Central part on the boarder of Wisconsin that about a 1 hr 45min from Chicago

Cool, I'm about an hour straight south of you on I-39. Nice to have someone else in the area that knows a little about this stuff!

yoheer

01-26-2023, 11:05 PM

I installed new injectors. I have its specs so I know flow rate and offsets.
What about Injector offset adder table?
Should I zero it out or just leave it alone?

spfautsch

02-01-2023, 04:17 AM

As best I can recall, yes - that is / has been the prevailing wisdom on this topic. For the $EE mask (again, as best I can recall) it's believed that this table contains signed integers that are all negative.

Just for a sanity check though, can you verify the address of the table you're talking about pls? I've been swamped at work for the last couple weeks and simply haven't had time to delve into tuning stuff.

yoheer

02-03-2023, 09:12 PM

0x129F5

spfautsch

02-05-2023, 08:23 PM

That's the one. Yes, zero it if using modern injectors.

kur4o

02-05-2023, 08:34 PM

That table compensate for non linear behaviour of fuel flow on low pulse widths[upto 4ms with patch]. Too bad lt1 code don`t allow negative corrections of it, since some injectors needs negative offset.

If you have data use it or extrapolate some. Otherwise you will have non-consistent fueling with less than 2-4ms pulse width, wrecking havoc on your tuning efforts.

yoheer

02-05-2023, 08:34 PM

How to fill this table using this data?

https://documents.holley.com/accel_injector_specifications_150136.pdf

spfautsch

02-05-2023, 09:04 PM

Search for "injector flow rate knee" - it's critical to understanding what this is correcting. At lower pulsewidths the injector has a different flow rate. Above this inflection point (say for example around 2ms) the injector's flow rate is more or less linear.

To vastly oversimplify, the injectors GM used in these early systems had a lower flow rate below the inflection point, thus requiring an adder to make fuel metering accurate.

Conversely, most modern injectors have a higher flow rate below the knee, requiring subtraction. The $EE mask is incapable of this, which is why the only thing that can be done to this table with modern type 3 injectors is to zero it.

yoheer

02-05-2023, 10:57 PM

I roughly understand
I believe mine are type 2 injectors
Could you please explain me, how to manage this table, using data from the table below? (If there is enough data and if it's possible to do it.) As an example.

spfautsch

02-07-2023, 05:26 AM

I wish I was of more help, but that's unlike any injector characterization I'm familiar with. Also, possibly more important than low slope compensation (the purpose of the 0x129F5 table) is a lack of an offset vs voltage table.

Fast355

02-07-2023, 06:34 AM

steveo

02-07-2023, 08:01 AM

if its a flow rate modifier cant you just scale the injector constant to bias the table?

Fast355

02-07-2023, 10:38 AM

if its a flow rate modifier cant you just scale the injector constant to bias the table?

I was thinking more about this. NO injector out there is going to have a Negative Short Pulse Adder used in a GM vehicle even though GM may have calibrated some of the later vehicles with negative numbers. The negative numbers in that situation are a skewed value to correct something else.. The way GM uses that table in the operating systems I have physically looked at is to correct the delivered fuel charge of the theoretical whole. Same with the offset table. While it is true that injectors typically flow more in the early non linear area, to make the actual injector delivery linear with pulsewidth, it has to have a positive value. In the Injector Dynamics diagram, you can clearly see the theoretical white line and the actual fuel delivered in the red line. The red line will always be lower than the white.

http://injectordynamics.com/articles/gm-injector-characterization/

steveo

02-07-2023, 06:11 PM

from the standpoint of actual tuning output -- i have always just left the table stock and tuned TONS of lt1s without issues

here's some reasoning for you

with a reasonably sized injector the threshold for non linearity is low enough where at worst it's basically at idle and transition off-idle, or at best your engine would damn near be stalling before you got there because it's way below normal operating range.

look at the stock table. it starts to build a curve at 1.7msec but barely, in effect it doesn't do much until below 1.0msec

i don't know what you guys are finding for pulsewidths at idle, but i usually see 1.5-2.5msec hot. i can't ever remember seeing an idle below 1.5msec pulsewidth.

if you DO cross that threshold, it's because you probably have a gigantic engine with a big cam and really big injectors, and lets not kid ourselves, idle fueling on engines like that is a joke. you're basically pissing into a river, there's no real target, you just play with it till it runs well.

so i'd stick with either zeroing the table or just ignoring it and just botching your airflow (ve or maf) in that region to get your fueling in the ballpark, can't imagine it making a gigantic difference, unless you run gigantic injectors and the 'knee' or whatever you'd call it suddenly encompasses a real operating range

spfautsch

02-07-2023, 07:14 PM

yoheer

02-07-2023, 07:21 PM

Well, it makes sense

Fast355

02-07-2023, 10:58 PM

Just a quick question along those lines steveo - do you know, is the pulsewidth reported in the $EE datastream before of after this adder?

Your point is valid however - the operating range we're talking about here is going to be very rarely encountered for reasonably sized injectors.

No, you'd need to skew the entire offset table. The slope of the injector is assumed by the fueling equations to be a linear constant (even though it rarely is).

Edit: also, it's not a flow rate modifier. It's correcting delivered fuel mass for a region of the injectors flow curve that doesn't match the injector flow constant slope.

Though I'm scarcely qualified to teach a remedial course in fuel injection flow characterization, if I get bored enough I'll try to draw up a couple graphs to illustrate the difference between older type 1 / 2 knees and what a type 3 injector looks like. The graphs Fast355 referenced on injectordynamics are of type 3 injectors.

The topic I'm more interested in is how would you advise yoheer to proceed given the injector characterization posted here (http://www.gearhead-efi.com/Fuel-Injection/showthread.php?7571-95-lt1-injector-offset-questions&p=97360&viewfull=1#post97360)?

ACCEL 150136 - 36# Hr Fuel Injector Specifications
Drive Circuit: "Saturated", R-C Voltage Suppression, 14.0 VDC
Coil Resistance: 14.5 ohms
Fuel Compatibility: Standard Gasolines and Ethanol Flex Fuels
Fuel Pressure: 300 kPa (43.5 psi)
Static Flow Rate: 252 gm/min n-Heptane
Dynamic Flow Rate: 7.56 mg/pulse at 2.5 ms, 10 ms period (100 Hz)
Approximated Time Offset: 0.70 ms
Approximated Slope: 4.20 mg/ms
Minimum Linear PW: 1.38 ms
Linear Flow Range (SAE): 15.3
Opening Time: 1.35 ms
Closing Time: 0.67 ms
SMOV: 4.23 volts

The point you are missing is that the angle of the knee does not matter. It still going to deliver less than the theoretical delivery base off pulsewidth thus the numbers will still need to be a positive number. The injector that has more initial delivery will just have lower values in the adder table. The injector that has less flow initially will have larger numbers. Either way you still have to add to the total pulse width to get the full fuel charge.

I spent some time messing around getting the injector data correct on the 42# Ford 6.2L "Raptor" injectors in my P59 run 383 with a L31 Marine intake. Using the data in the Ford Raptor PCM, at a differential pressure of 58 psi, the break point corresponds to 1.667 msec. Over 1.6 msec the injector flow is characterized by the high slope values, under 1.6 msec it is the low slope. The low slope value has a higher flow rate, but the values are 0.121% different. I used an exponential curve to mathematically approximate the difference. At 0.06 msec commanded pulse width the injector in theory needs 0.2 msec more to get that 0.06 msec desired flow amount from that point on the difference reduces until it disappears into a number the P59 will not even save at 1.64 msec. In the grand scheme of things that is almost nothing. My idle pulse width is ~3.5 msec at hot idle. During deceleration the pulse width drops to 2.2 msec. I would need roughly double the injector size before the short pulse adder really came into play. As said before this would make a difference on an engine with really large injectors like a turbo build, but with reasonably sized injectors its not something that would ever come into play. Even with double the injector size, it would still likely idle above 1.6 msec and any issue in deceleration could be compensated for by activating DFCO for a brief period. Ford did exactly that on the mid 90s Cobras with the 351 to get them past emissions and smooth out surging that might otherwise exist from inconsistent fueling during deceleration.

Fast355

02-07-2023, 11:09 PM

This is what I am running for a short pulse adder. With the offsets calculated for 58 psi and using the high slope flow rate calculated for 58 psi, runs perfectly. I have a LS3 MAF on it in a 100mm tube. Runs on the Lingenfelter MAF transfer for a 100mm MAF like GM calibrated it.

steveo

02-08-2023, 12:25 AM

Fast355

02-08-2023, 12:44 AM

seriously i wouldn't worry about it on an LT1. it's just not a precise machine.

even injector voltage offsets, if you don't have them, are no big deal. unless your alternator shits the bed it only ever uses two cells of that table anyway. just rough in the injector constant and throw the offsets in if you have them.

it's like obsessing over tuning the far top right corner of your VE table, which unless you have a standard transmission and floor it from a standstill in 6th gear, you absolutely can't reach, and even if you did, fueling accuracy in that region doesn't matter.

in most of my tuning i never touched that and they were dead on accurate with no hiccups in drivability

focus on things that make a difference. kur4o's EOIT stuff probably makes way more of a difference than all this

Agreed! Some guys can stress out to the nth degree, but it does not really matter much. The better the data you have the better off you are; that being said it is not the end of the world. Tune it so that the air/fuel ratio is right and you are golden.

This was with Ford data out of a stock Ford PCM converted to GM which some people claim will make the GM run like poop.
https://youtube.com/shorts/TRVDXmOpSHA?feature=share

steveo

02-08-2023, 05:56 AM

there definitely are temperamental machines that require incredible precision.... with high compression and tons of boost you can often be .1 lambda point or 1 degree of timing in between scalding power and death. you'd figure that you'd want to really nail your injectors down, but guess what, even on those machines people often aren't screwing with injector parameters that much. my 25psi boost buggy has a 32 bit ecm with only 5 cells for injector latency and that's it, and injector timing probably is all thrown through some proprietary equations that match with variable intake cam timing. when i put completely different injectors in there, i just left that table alone too.

spfautsch

02-08-2023, 05:57 PM

The point you are missing is that the angle of the knee does not matter. It still going to deliver less than the theoretical delivery base off pulsewidth thus the numbers will still need to be a positive number. The injector that has more initial delivery will just have lower values in the adder table. The injector that has less flow initially will have larger numbers. Either way you still have to add to the total pulse width to get the full fuel charge.

Actually, after going through the exercise of sketching out the slopes yesterday, I'm no longer missing that point. You are correct. As I'm looking at the low pulse adder table for my '01 LS1, it's a typical adder table. Though I didn't originate it, I guess I'm guilty of spreading bad information.

Fast355

02-08-2023, 06:15 PM

Actually, after going through the exercise of sketching out the slopes yesterday, I'm no longer missing that point. You are correct. As I'm looking at the low pulse adder table for my '01 LS1, it's a typical adder table. Though I didn't originate it, I guess I'm guilty of spreading bad information.

I know the feeling there. It threw me off a bit too having just been messing with and converting injector data. Then a light bulb clicked on when I saw those Injector Dynamics graphs.