95 lt1 injector offset questions

[Terminal_Crazy]

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]

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]

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 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]

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_Cra...se_start_1.jpg
http://www.sand-hill.uk/Terminal_Cra...Log/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]

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]

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]

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]

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.