E40 H/C LS2 need help

[crazycoupe]

Hello my name is Christian, I am new to tuning but very mechanically inclined and understand most of the tuning "lingo". I did modify the harness myself as well as assemble the engine. I have been all over the forums searching and trying new adjustments but Im still going in circles. Im looking for help understanding how and where to make adjustments but seem limited on info out there with this dreaded E40 PCM. Right now I'm trying to get it to idle and run smooth enough to get basic things done while finishing the car. No WOT pulls can be made right now but i would like to be able to move the car around under its own power. Any help is very much appreciated as I really want to learn and understand these systems. I have checked the repository and see nothing I can use as a guide , Here is the rundown

1976 Camaro

The LS2 was just rebuilt stock bore 0 miles

Everything is from 2005 corvette M6 Z51
LS2 with TSP CnC 243 heads
MS3 cam .605 .610(238 242) 111 ICL adversised 287 291 valve timing @.050 INT 8 BTDC, 50 ABDC
EXH 52 BBDC , 10 ATDC
Stock TB
Stock MAF
Stock Intake
stock LS2 Injectors
1-3/4 long tubes with an extension pipes for now no exhaust
TR55 plugs Gapped @45
running 91 octane
regular weight flywheel

[Lakegoat]

Nothing wrong with an E40. Especially for a n/a application. Start with a stock file and go from there. You should add about 15% to the base running airflow in the 400 to 1200 rpm areas. It should at least run. Start tuning the fuel trims.

[5FDP]

The use of the wideband o2 sensor will also make this much faster too, you need one anyway to properly dial this all in.

[crazycoupe]

Lakegoat I have gotten it to idle but it will gas you out immediately and i fear washing out the cylinders as the rings and bore are fresh. Am I over thinking that?




I do have a wideband just need to weld in a bung. Can I shut the O2s off and use the wide band just to get a base? or will it go crazy once they are back on?

[5FDP]

If the calibration is basically stock with minimal changes it won't be washing the cylinders out with fuel. Doing only a cam/heads and exhaust work isn't going to cause the computer to throw all the fuel at it because you haven't told it that it needs more fuel. The computer will likely see that it's lean once it reached closed loop operation and tries to add fuel back in to achieve stoich.

One thing for sure though, make sure you are running the proper fuel pressure of 58psi. If you are running it higher it could cause a rich condition as it would force more fuel into the engine each time the injector opened up.

You could run it without the o2 sensors in open loop and switch back to using them later. That has to be done anyway when tuning with the wideband but I highly suggest welding a bung in place and finishing the exhaust. Only having the exhaust done 10-15in past the sensors can skew the readings and cause issues.

[Lakegoat]

I hope your extension pipes on the exhaust are about 2' long. Otherwise your O2's will be reading incorrectly. What do your stft's say now at idle,---if you have the long extensions? If you are trying to tune the low rpm areas and are running out of the headers with no wideband, you are really going to be chasing your tail. If you have a nice 2-3 ft extension, you can use the O2's to get your fuel trims "close". I would fail the maf, turn off dfco, cot, Ltft's, max out dynamic airflow, and set up afr error in your chart and get cracking on the ve table using Stft's. Then reenable maf, fail the ve table, and tune the maf. It shouldn't be that far off. At least you can get the low rpm areas close while you are waiting to hook up the wideband. Don't forget to smooth the ve table after every write and be sure and clear fuel trims in the scanner before every scan. There is a lot more, but somewhere to get started.

[SultanHassanMasTuning]

post the calibration...

[crazycoupe]

If the calibration is basically stock with minimal changes it won't be washing the cylinders out with fuel. Doing only a cam/heads and exhaust work isn't going to cause the computer to throw all the fuel at it because you haven't told it that it needs more fuel. The computer will likely see that it's lean once it reached closed loop operation and tries to add fuel back in to achieve stoich.

One thing for sure though, make sure you are running the proper fuel pressure of 58psi. If you are running it higher it could cause a rich condition as it would force more fuel into the engine each time the injector opened up.

You could run it without the o2 sensors in open loop and switch back to using them later. That has to be done anyway when tuning with the wideband but I highly suggest welding a bung in place and finishing the exhaust. Only having the exhaust done 10-15in past the sensors can skew the readings and cause issues.

I will check the fuel psi but I am using the 99 vette filter. I am waiting for a stainless o2 bung at the moment. the extensions are 18" past the o2 and turn 45 degrees. I downloaded a stock tune file went from there adjusting idle commands and took out fuel from the VE low rpm 400-2800 smoothed it out as well. since that it is much better as far as stink and quality. I do believe I need to disable some items in the misfire area as I record a bunch. I will post the tune and log file in a bit

[crazycoupe]

Lakegoat, Im not sure how to adjust anything you mentioned with the maf but I will look it up. thank you for the info

[crazycoupe]

here are the files. Although I mentioned misfire issues they seem to be absent in this log.

[SultanHassanMasTuning]

christians Camaro idle and VE adjust cam base SD.hpt

E40 i would go SD and dont mess with MAF, you can keep your maf in place of intake for IAT


try this out and let us know....