Idle AFR changing whilst Idling

[Terminal_Crazy]

Hello
I've been running the car all morning flushing out oil from the coolant.
It's running an OLSD tune at the moment still set at 13.0 :1

Car starts at 10 and sits around 12.5 .

Occasionally when i've checked the temp, the AFR is around 15 then later back at 12.5.

It fluctuates about 0.5 point either side any way, but why should it decide to run leaner for a while.
It shouldn't move should it?

I think everything is turned off or shut down that's possible.

Any thoughts

'95 LT1 if it'snot in my sig.

Ta.
Mitch

[kur4o]

A log and a bin should help alot.

[Terminal_Crazy]

Typically i wasn't logging then.
I will when i find out where the oil is getting into the coolant from.


Mitch

[kur4o]

I don`t want to scare you but if there is no oil cooler in the radiator, the options are very limited.
A cracked block is one option. In the heads there is no pressurised oil. If it was a gasket problem, it will be more likely a coolant in the oil problem.

Did you see the actual afr fluctuating at the wideband.

[Terminal_Crazy]

It's a '95 Z28 LT1 with the KC4 Oil Cooler (Coolant runs around the Oil Filter type).

The Oil is fine apart from it disappearing.
I suspected the Edelbrock LT4 Inlet Manifold but have re machined the port faces.
It is however leaking oil now from the rear wall since i went to synthetic after the rebuild.

I've read a bunch of threads about the '95 KC4 leaking oil into the coolant.
'93 and '94 seem to be better and by '96 it wasn't available.

Not had chance this weekend to pull it off and check yet.

Not sure yet also whether to delete it or to just install a full oil cooler.


Thanks
Mitch

[Terminal_Crazy]

Did you see the actual afr fluctuating at the wideband.

It always fluctuates at idle upto around half a point either side but I'm not to bothered about that.

It was running for a good hour mainly sat around 12.5 but one time i looked it was sat at around 15:1.
It never missed a beat, never changed tone or speed as far as i noticed.
AFR was just up there.
10 mins later it was back at around 12.5.

I'll log it next time i run it just to check.
I just thought it was a bit weird as everything is turned off that can be in tuner pro.

Thanks
Mitch

[kur4o]

Oil cooler is the main suspect. Extrenal leaks can`t get into coolant flow.

You can bypass the oil cooler real easy.
With a hose from radiator to pump and than check for oil leak from the disconnected pipe.

At idle if you see more than +- 0.1, 0.2 afr change, the idle individual cylinder trims need tuning.
They are really hard to tune though. Playing only with these trims you can get afr change from 11 to 15.

You might have a exhaust leak or bad sensor.
Check with the stock o2 sensor readings to confirm which side leans out.

[Terminal_Crazy]

I bypassed the cooler and ran the car.
Oil started weeping out of the cooler pipe so i’ve Deleted it for now.
The coolant recovery tank was also full of oil so it’s all been flushed out and cleaned.

I’ll log the idle next time I play with it and get back.

Cheers
Mitch

[Terminal_Crazy]

Ran and logged the car today.

Still running OLSD with flat AFR at 13:0.
This log was just from cold startup & idle.
12277
12278

O2's and plugs only have about 1k miles on them.

In my previous log it showed similar results so in this I've increased the rhs cyl trims from 1.03 to 1.047.
However this could be a wrong assumption on the rhs being lean.

Measured exhaust temps 1" out on header
FRONT
165 163
196 182
183 169
171 153

EEHAck idle cylinder test
cyl 1 28.2
cyl 2 29.2
cyl 3 27.9
cyl 4 28.3
cyl 5 28.2
cyl 6 28.5
cyl 7 29.6
cyl 8 28.5

Where next?
Do i change plugs & O2 Sensors anyway as I'll have to remove them to check them anyway.

Mitch

[kur4o]

There might be some mechanical problem with right side. Cylinder misfiring or injector problem. Number 8 seems a little cold.
Exhaust leak is also a possibility.

Right side o2 goes flat and it also shows lean at same time on the wideband. So sensors should be ok.

[Terminal_Crazy]

I'm running out of ideas.
Since rebuilding the motor I've checked everything multiple times.
Pretty much everything is new except the pan and block.
It's had split BLM's and had O2 differences.
It's on it's 3rd set of injectors, 2nd set of NEW o2's

I'm pretty certain the manifold (Edlebrock LT4 performer was) passing air underneath, the ports were wet when i emoved it.
I've remachined it (bought a mill to do it) but not 100% convinced it's sealing the ports.
If I end up removing it I'll have to re mill it and cut down some of the larger sealing areas.

Exhaust leak is pretty unlikely, been over them many times, including the egr ports. ** Might just recheck the M22? plugs i fitted to the headers 9 years ago ***

Cylinder misfire possibly but Steveo's EEHack disdn't highlight any issue with the cylinder test which was straight after the uploaded datalog where the RHS has pretty much flatlined.

Odd how both sides drop around 300Secs and by 550 the RHS has recovered until 1200 secs when it starts to drop again.

Weird !

Thanks
Mitch

[spfautsch]

One of kur4o suggestions was cylinder misfiring - wouldn't that generally cause a rich condition when running open loop?

Are the m22 plugs you mention blocking off the AIR ports?

Can you reproduce this symptom from cold startup?

As you say this really is odd. I would think the lazy right narrowband reading could be indicative of an open heater circuit, but that doesn't explain the very distinct event around the 5 minute point in the graph that's clearly effecting the wideband as well.

[Terminal_Crazy]

One of kur4o suggestions was cylinder misfiring - wouldn't that generally cause a rich condition when running open loop?

Are the m22 plugs you mention blocking off the AIR ports?

Can you reproduce this symptom from cold startup?

As you say this really is odd. I would think the lazy right narrowband reading could be indicative of an open heater circuit, but that doesn't explain the very distinct event around the 5 minute point in the graph that's clearly effecting the wideband as well.

Hi
I think Misfire causes it to run lean as it measures the O2 content which has just jumped by 25-30%
The M22's block off the AIR ports (1 per header) ...seem OK

Reproducible with tonights log. The dip is there around 4-5 mins but isn't important as motor is only 50c then.

Not as odd as tonights log.
Does anyone want to have a laugh at this.

Checked the M22 bolts in the headers. Seemed OK, no blowing.

Previous: LOG a30 idle: RHS O2 sensor dropping LEAN & WB AFR rising to 16-8...

LOG a30-2_idle
Ran another idle test & used EEHack to play with the timing & AFR
Graphed with EEHack
Top graph AFR Target & Wideband O2 AC Pressure
Bottom graph Left O2 Oxy Sensor mV & Right O2 Oxy Sensor mV



Warmed up car on same bin till 90c | same as previous log
Both drop around 4-5 mins | No idea but not important as car is on 50c here
|
log @ 9k dropped 5 degrees timing 32 ish | no observed change
|
9k8 AFR 14.7:1 | Both O2's drop off the scale
10k2 14.0:1 | O2's pick up slightly
10k6 13.0:1 | as normal
11k 12.5:1 | better
11k5 12 :1 |
|
12k4 timing +5 degrees (37) | no real change
12k7 timing -5 degrees (32) | no real change
13.1 AFR 13.1:1 | both O2's bouncing about
|
15k1 cut cylinder 1 - flat lined BOTH o2's ??? |
15k2 cut cylinder 2 - flat lined BOTH o2's ??? |
15k3 cut cylinder 3 - flat lined BOTH o2's ??? |
15k4 cut cylinder 4 - flat lined BOTH o2's ??? |
15k5 cut cylinder 5 - flat lined BOTH o2's ??? |
15k6 cut cylinder 6 - flat lined BOTH o2's ??? |
15k7 cut cylinder 7 - flat lined BOTH o2's ??? |
15k8 cut cylinder 8 - flat lined BOTH o2's ??? |
|
16k5 Settling back |
|
16k6 AFR 9.1:1 | stable
AFR 10 :1 | stable
17k5 AFR 11 :1 | stable
18k AFR 12 :1 | slightly eratic
18k5 AFR 13 :1 | back to very eratic


Weird results, but I don't know what it tells me other than it likes fuel.

The only thing i'm aware of in the bin that's not correct is the Injector Flow rate I've lowered to 37 to scale the VE tables down.
Injectors are Now 42lb Bosch III Blue Demon (EV1 plug EV6 style) from FIC
Also had previously
30# VENOM Rated at 30 lbs/hr @ 43.5 psi
and (Bosch III FIC 312.6 / 10.2 = 30.64)

Why would cutting 1 cylinder flatline both O2 sensors or is 100 data logs not enough to recover ?

The two EEHack data files are in the Zip


Thanks
Mitch

[kur4o]

I need to see some cruising logs at constant speed, load to confirm some ideas.

[Terminal_Crazy]

I need to see some cruising logs at constant speed, load to confirm some ideas.

Thanks, I’ll post up the last run that I did tomorrow.

[Terminal_Crazy]

Thanks, I’ll post up the last run that I did tomorrow.

I've definately been fighting this since I built the motor.
I've uploaded the last 2 decent runs I did.
The bin used will vary slightly but I've only changed VE tables as I've been chasing the WB AFR up and down.


Thanks for looking

Mitch

[kur4o]

Still not sure if it is a mechanical problem, bad tune or a mix of both.
Do you have older logs with the other sets of injectors.

You got constant knock at lower loads. Mixed side intermitten lean condition at low load conditions.
I suggest you start all over with your tune. I can make a starter bin and work from there.
That way we can rule out the bad tune hypotesis.

[Terminal_Crazy]

Still not sure if it is a mechanical problem, bad tune or a mix of both.
Do you have older logs with the other sets of injectors.
It's always been off 1 side. Nothing has ever made much difference.
Injectors we replaced. Then swapped side to side & centers to outside.
Not sure if i can ID logs with the previous injectors, I'll have to check.

[QUOTE}
You got constant knock at lower loads. Mixed side intermitten lean condition at low load conditions.
I suggest you start all over with your tune. I can make a starter bin and work from there.
That way we can rule out the bad tune hypotesis.[/QUOTE]

Again it's always been like that. Since going OLSD the car has run and felt miles happier especially at 11-13:1

I'll try anything you can think of.
A new tune would be interesting.
MAF is still on the car, just disabled as I have been trying to get the VE sorted.

This probably explains why the VE tables end up looking like a toblerone!

I still think this could be an issue with the inlet manifold, vac leak underneath.
I switched to synthetic oil a couple of hundred miles ago.
Car still drinks oil andsince the switch the manifold has started leaking at the rear china wall.

I've been reading/Youtube on PVC valves so can check that tomorrow night. Prompted by the rear seal starting to leak.

I'm open to suggestions on how to pinpoint the Vac leak to the manifold before I pull it. 2 sets of gaskets cost me about 80 USD last time

Another thought on something I read was the bolts for the push rod guides on the AFR heads breaking into the Inlet Ports.
I remember using LACO Thread sealer on the Head bolts and pretty certain I used it when installing the push rod guides.
Something else to check.


Cool.
I await your response.

Thankyou

Mitch

[Terminal_Crazy]

OK
Got a couple of Datamaster logs with the 32Lb Bosch III's.

Interested to see what you see in them !

Thankls
Mitch

[kur4o]

Earlier logs have much more consistent 02 data.
I suspect the injectors just don`t open at low PWM{below 2ms} condition at random intermitten rate.
It could be the pcm can`t handle it or the injectors are garbage.

You can bring back the smaller injectors. Reload factory VE, Spark, Individual cylinder trims and all knock retard related tables.
Fix the injector data flow and offset. Low pulse width correction are really important. I see all zeroed at the latest bin
Increase cylinder volume to 935.

Reseal the m22 plugs and retighten the header bolts.
The knock could be real or false. Lowering total advance will show if it`s real
If it is false you will have to find out what`s causing it.

[Terminal_Crazy]

Earlier logs have much more consistent 02 data.
I suspect the injectors just don`t open at low PWM{below 2ms} condition at random intermitten rate.
It could be the pcm can`t handle it or the injectors are garbage.

You can bring back the smaller injectors. Reload factory VE, Spark, Individual cylinder trims and all knock retard related tables.
Fix the injector data flow and offset. Low pulse width correction are really important. I see all zeroed at the latest bin
Increase cylinder volume to 935.

Reseal the m22 plugs and retighten the header bolts.
The knock could be real or false. Lowering total advance will show if it`s real
If it is false you will have to find out what`s causing it.

OK thanks.
I'll check a few things this weekend and chuck the 32lb Bosch III's back in.
Anyone got ANY specs for the Bosch III's or any recommends for anything better with some proper specs?

Why the cylinder size to 935. The motor is a 383 so cyl volume should be 783.70cc

IS the injector adder the time taken for the Injector to open and stabilise flow?
Would increasing this make any difference? (presumably not if the injectors can't open anyway in this time )
Zeroing them seems to be the only consistant info I have for these.

How would the PCM/injectors cope with a huge cam that required bigger injectors then as the the fuel requirements wouldn't be much different at idle so opening time on a bigger injector would be similar.
What's a stock injector idle pw time for comparison?


Advance changes never seemed to make any difference.
Running pig rich does which is why i still possibly suspect the manifold, if it's not the injectors.
I'm 99% certain there is NO _usual_ vacuum leak anywhere. Everything has been gone over many times.
Even knock sensor has been replaced twice.

As to the manifold, I'll log again and pump propane into the rocker cover with the PCV valve blocked off just to see.


Thanks again
Mitch

[kur4o]

Do you have the part number on bosch injectors.
Low pulse adder is to compensate for non linear behaviour at very short opening.

You need to inrease cylinder volume, because pcm cant see over 100% ve. That way you keep ve resolution.
The value I gave you is appoximate and may need corrections.

Investigate any mechanical issues that may arise and affect the tune.
Felpro intake gasket are really cheap. Might worth a try if you suspect a problem.
Double check for anything that may produce a knock at the engine, exhaust pipes or body.

[Terminal_Crazy]

Do you have the part number on bosch injectors.
Low pulse adder is to compensate for non linear behaviour at very short opening.

You need to inrease cylinder volume, because pcm cant see over 100% ve. That way you keep ve resolution.
The value I gave you is appoximate and may need corrections.

Investigate any mechanical issues that may arise and affect the tune.
Felpro intake gasket are really cheap. Might worth a try if you suspect a problem.
Double check for anything that may produce a knock at the engine, exhaust pipes or body.

Hi
Injectors are from FIC - www.FuelInjectorConnection.com
Ordered 30lb Modified Bosch 3 Injectors ( Stainless later core )
Later ones were 42lb @ 3 Bar Modified Bosch Blue Demon 3 Fuel Injectors

No info on either of these. I've scoured the web - nada.

OK on the other info.
Just been looking at the Gaskets. The felpro's LT4 ports aren't as big as the AFR (or Edelbrock's) so far as i've found.
Also looking at plugs & O2 sensors.
I got squeeks, not anything knocking.

I'll pull plugs, do vac check, PCV check & propane this weekend

ps @ Scott Pfautsch: Did you ever get info from FIC on the Bosch injectors?

Thanks
Mitch

[spfautsch]

Double check for anything that may produce a knock at the engine, exhaust pipes or body.

I'm running nearly identical roller rockers and have a far worse amount of what I believe is false knock that bands heavily around 1700 rpm. I've been all over the car looking for exhaust system interference and came up with nothing. I don't understand why it's better in hot and humid conditions and worse when the air temp and humidity drops. Reducing timing seems to make it worse. I've been wondering lately if it might be noise from my dual mass flywheel. But I think Mitch has a single mass setup.

One thing that might be worth looking at is the possibility that a lifter may be sticking intermittently and holding a valve open slightly.

[spfautsch]

Did you ever get info from FIC on the Bosch injectors

Nope, but mine are grey bodied LS injectors that I managed to find a partial offset table for. I may be giving you the wrong #s but I believe the PN that was left on the injector body was GM 12561462 which crosses to Bosch 0280155931. Nothing along the lines of low pulsewidth compensation though. My table at 0x129f5 is also zeroed. I did however reduce my "minimal injector pulsewidth" constants at 0x126d5 and 0x126d7 to 0.56ms (0x25).

[Stokes1114]

Not sure if this will help at all, but ppl have been having problems with some of these bosch injectors on thirdgen.


https://www.thirdgen.org/forums/diy-prom/747539-bosch-iii-injector-sticky.html (https://www.thirdgen.org/forums/diy-prom/747539-bosch-iii-injector-sticky.html)

https://www.thirdgen.org/forums/diy-prom/728614-bosch-iii-injector-offsets.html

https://www.thirdgen.org/forums/diy-prom/730802-bosch-iii-injectors-not.html

[kur4o]

GM 12561462 is ls1 28 lb/hr at 4 bar pressure.
If they are stock I can get you the correct voltage offset settings.

The best injectors will be the gm stock production ones or ford SVO.
Cal data is readily available from stock tunes.
Ls7.ls9 are really big improvement but alot shorter and needs modification to fit.


I guess fic don`t provide injector data, because they don`t have one.

Wrong plugs can get you alot of pinging. If they heat too much.
Get us a pic of your current ones.
Maybe try 1-2 points colder splugs.

[spfautsch]

GM 12561462 is ls1 28 lb/hr at 4 bar pressure.
If they are stock I can get you the correct voltage offset settings.

None of these are stock - FIC remans / modifies injectors. They remove the pintle cap, clean and replace with caps (and possibly do something else) to give the flow rating the customer orders. Normally they grind off all part numbers and paint the injector bodies light blue, but in my case they only removed the Bosch P/N and left the GM P/N. They advertise these sets as flow matched Bosch D3s and that they will come with a flow test printout, but mine did not. Mitch was able to pester them enough to send offset data for his, but I didn't bother because mine idled well using the SVO offsets and minimum PW I found @ 3 bar.

This is purely speculation, and I hate to bag on FIC but it's possible Mitch has a mix and match bunch of injectors that may or may not be electromagnetically similar but are minimally flow matched (at some pulsewidth). I ordered mine to flow 42lb/hr, and based on my VE trims they flow closer to 44. But thankfully I know mine at least match electromagnetically. When pull my engine next month I plan on sending mine to a third party to flow test.

[Terminal_Crazy]

Ok I’ve got a few things to pull apart and check again tommorrow.
See what I find.

Most info I’ve found so far on the injectors is to just zero the low pw tables.
This motor is idling about 1.8ms with the 42lb
I don’t see the voltage offsets having a major effect on the fueling once the motor is running. Voltage is pretty stable by then.

Thanks
Mitch

[spfautsch]

Most info I’ve found so far on the injectors is to just zero the low pw tables.

As long as what you have are all Bosch type III I think you should be fine zeroing that table. But without any part #s you're taking FIC at their word. If you have one or two that are completely different from the other six or seven except in gross flow rating, all bets are off.


I don’t see the voltage offsets having a major effect on the fueling once the motor is running. Voltage is pretty stable by then.

Cooling fans draw a fair amount of power, especially on high. It sounds like you've jettisoned your A/C but the blower and the additional draw of the cooling fans keeping the A/C condenser working make a noticeable difference, especially at idle when the alternator output is fairly limited. You also have an electric water pump right? All this stuff makes an impact on system voltage.

Long story short, I wouldn't dismiss offsets completely. I pay attention to the ECMVOLTS pid frequently enough I've considered making the "User Parameters" PID selections in eehack remember the last selection.

Edit: It may be reaching, but are your injectors painted? If so have you considered filing through the paint to see the color of the base plastic?

[kur4o]

Here are some good articles.

[Terminal_Crazy]

Thanks for those.
I’ve got a couple of Greg’s books.

Mitch

[Terminal_Crazy]

Little update on this issue.

Removed plugs from motor and they were oily/carbonized and sooty.

Checked the PVC valve and had tape stuck over the end where I'd tried to fatten the valve into the grommet.
Replaced valve anyway

Bought a cheap Endoscope off ebay but couldn't get a clear view of the cylinders.
Tried viewing into the inlet manifold port runners and again couldn't really see any definitive detail.

Made a smoke machine with a stainless chamber & a small compressor
Pumped several smoke pellets into the crankcase through the rocker cover.
had smoke forcing its way out of the dipstick hole
I could NOT see any smoke in the manifold runners which I suppose is good in a way.
Certainly ticks the box the manifold is sealing.

Resealed the AIR tube plugs in the exhaust manifolds with epoxy metal and replaced.

Started the car and the RHS O2 started to drop after a minute or two.
Vacuum gauge was pretty stable.
Tailpipes were smoking white quite a lot, it's freezing and snowing here.
So I let it warm up and did a water decoke into the inlet manifold.
Used about 1.5 pints over several minutes.
The O2's and wideband all flatlined.
Retarded the timing with EEHack (Thanks Steveo) to pump heat into the exhausts.

After another 5 minutes or so the O2's came back on line
Wideband followed suit.
The smoke has cleared up from the tailpipe.
The smoke from the rear of the inlet manifold also had cleared up so PCV seems to be working now.

Car is idling pretty sweet.
The RH O2 sensor is now consistanly reading higher than the left as i'd fattened it up slightly which it has never done before
and the wideband reading was also more stable around 12.5

I'm just waiting for new O2 sensors and plugs to arrive.
I will monitor this for a while before changing anything over and see what develops.


Thanks guys
Mitch

[Terminal_Crazy]

OK guys, quick update on this.
I feel pretty certain that
a) the injectors are OK
b) the manifold is NOT leaking from underneath.
c) O2's were/are fine.

O2's arrived so i changed them out to rule them out.
I have a new set of plugs to go in but just cleaned the previous ones up for now.

I've been through the entire bin and compared it to the original Stock Z28 M6 Bin.
I put all the Closed loop delays and CORRCL values back to stock.
Individual cylinder fuel trims and Timing.
Injectors are currently sized at 41lb not the 42 they are rated at. Only 2-3% off.

The car ran much nicer and 1 could take the clutch up in first at idle and the car would roll 5-7mph without me losing any teeth with the surge.
On the initial warmup I've raised Open Loop AFR Target starting at around 14.1 but the wideband is reading 10.5 to 11
I don't know how I can raise that up much more?

The O2's drop at exactly the same point as the last 3 logs, 49 Degrees C to 56 Degrees C
The Injector constants don't change much, The LHS O2 bounces around, the RHS hits the floor. I suspect this could be plugs, fouling from too rich at startup maybe?
By 56 degrees C the O2's both recover and read a steady 900mv until CL at 60 degrees C.

Used Steveo's Trimalyzer to get the VE tables back into shape. They are starting to push Low 90's%.
Some tweaks to the Individual Cylinder Fuel trims is bringing the BLM's back into shape, within 121-129
The car is currently happier now than previously in CL and the Wideband is much closer to the req AFR the previously.

Other than using an IR temp probe or 4 Widebands is there any better way to balance the fuel trims.
That was the reason I was asking about identifying the cylinder in the log with the Cyl ID.
I guess there aren't any messages available to trim cylinders individually?

Thanks
Mitch

[spfautsch]

Since it's a relatively easy procedure I'd be interested to see if you swapped your four right / even bank injectors for your four odd bank injectors, if the flatlined O2 follows the injectors.

I too would be interested in developing a more scientific yet practical approach to individual cylinder trims. Reading the exhaust temps with IR feels like an exercise in futility. I've been searching for economically feasible thermocouples and RTDs and have been coming up empty. I was intending to use 1-wire DS18S20 sensors until I refreshed my memory with the datasheet and recalled they were rated only to 257F, not C.

[Terminal_Crazy]

Since it's a relatively easy procedure I'd be interested to see if you swapped your four right / even bank injectors for your four odd bank injectors, if the flatlined O2 follows the injectors.



I've just been back through all my earlier logs to when I installed the injectors and they were doing it back then 49-55 Deg C
I had started using EEHack at that point so need to fire up data master to see earlier logs with the other injectors.

Thanks
Mitch

[Terminal_Crazy]

OK, just checked some of the earlier logs with the smaller injectors (in datamaster) & I can't seem to see this effect.

I did check the MAP sensor this evening and there was a small smear of oil underneath so i've seated it on an O ring to see it that does anything.

If I don't get called out this weekend I think I might just swap the injectors around to see where they end up.



Mitch

[dzidaV8]

Older ECMs had a table with O2 voltage offset based on coolant temp. I can't find it in EE, but maybe it's not mapped? Just a thought.

[Terminal_Crazy]

Thanks for the input & feedback guys.

I think i'm going to bin these injectors off & get some new ones if anyone has any good suggestions.

I've set the voltage offsets up as per the calcs i was given.
This got the PW up into the 2ms range for idle but the VE tables went to pot.
As I played with VE the tables keep maxing out and I'm back lying to the system with 38 for the INJ Constant with 42's in.

The RHS is going progresivly leaner the more I play.
When the motor is pig rich it's fine.
As I lean it back out it's less happy. It buzzes and vibes more.

I was going to play & swap them over or piss about with the older ones but then I've just got to waste more time doing that again so i'm biting the bullet and get another set.

Thanks
Mitch

[Terminal_Crazy]

The new injectors have arrived and i'm still dialing them in.
The car is definately feeling different.
The low speed surge is back but the current .bin is heavly copied from the LT4 .bin i have rather than my previous setup.

It feels to have more power up top.
It was spinning the wheels in third around 78mph without much effort.
The fastest RPM i wound it to was 5500 at 67mph.
It felt higher but the roads are just above freezing.

The idle isn't as sweet yet as before.
Fueling is still a bit off on the Individual injector settings, but the VE table is a much smoother shape and has a much wider spread of values than previously.

So so far looking good.

Thanks
Mitch

[kur4o]

Do you have some data sheet for the new injectors?
If you have ls1 style injector data you can try my newest patch.

What is that lt4 bin you have? As far as I know lt4 was introduced 1996.

[Terminal_Crazy]

Do you have some data sheet for the new injectors?
Hm, only the usual...
Static flow @ 3, 3.5 and 4 bar
Dyn flow 50% duty, 3000 pulse/min 10ms ' 3 bar
Dyn flow Idle duty, 800 pulse/min 1.5ms @ 3 bar

And a list of Dead times (Latency) - Voltage vs ms

So far the VE tables are settling down nicely using Steveo's Trimalyzer, so a happy camper.


If you have ls1 style injector data you can try my newest patch.
Maybe when i get these up to par.
Is that the fixed fuel pressure one?
I presume i could extrapolate the data from the other Fuel pressure data?

Would that work by disconnecting the vac line to the fuel regulator?
What's your opinion on the Aeromotive one as I was looking at them this last week esp. with a fuel gauge.
How good is the stock unit (23 years old now)?
What sort of power would the stock fuel pump be rated for?

I think I remember reading Steveo damping the map sensor response down to smooth the pulses to the Fuel regulator, Any thoughts on that?


What is that lt4 bin you have? As far as I know lt4 was introduced 1996.
That was in the recent attachment on the LT1 diss zip.
I can't remember who posted it.
I just picked bits of the LT4 tables out that I liked compared to the stock Z28 vs my recent tunes.

Thanks
Mitch

[dzidaV8]

What's your opinion on the Aeromotive one as I was looking at them this last week esp. with a fuel gauge.


From my experience, those are overpriced and not reliable, one leaked right out of the box, the other started losing pressure after a few weeks...

[kur4o]

I am glad your getting closer to the perfect tune.
I only idle the car twice with the regulator so don`t have any usable data how good it is.
I put aeromotive 13107 since I have it from a long time. It is marked as 07/2011 unit, so shouldn`t give any real hints of the unit produced today.
Stock one looked pretty good and as long it keeps constant 3 bar pressure I wouldn`t bother replacing it.
I have plans to bump the pressure to 4 bars and installed it since the rail was off anyway.
I read somewhere that stock pump is good for 450hp, but I am not sure it will handle increased 4 bar pressure.

Patch will work with vacuum disconnected and constant fuel rail pressure.
You will need to have a good injector data though.

I checked a company called Injector Dynamics. They seem to provide good data, but are really expensive.
If you know how much hp you are making you can calculated the size of injectors needed. Bigger doesnt always mean better.