E38 ECM Wont Idle After 2Bar OS

[30thta436]

I have a 2007 Silverado with E38 ECM. After switching to 2bar OS the car will not idle on it's own. I can throttle it to keep it running, but it will not idle on it's own. I have increased and lowered the Airflow Final Minimum table to no avail. While holding the throttle to get it to run the AFR's are decent. What am I missing?

402ci 9.8:1 Compression
2.3L Whipple
225/236 Cam
Square Port Heads
Boost Reference FPR
850cc Injectors

[5FDP]

Did you populate your 3 new VE tables?

They are blank when you make the upgrade.

The file is tuner locked so it can't be viewed.

[30thta436]

Yes I populated them. I think I unlocked the file

Try ThisNo Tuner Lock.hpt

[GHuggins]

Still locked, but did you put the correct map sensor settings back in after the os upgrade? It automatically changes that with the OS install...

[10_SS]

How long have you let it idle or drive it? In the last 2 days I flashed back and forth between 2 different Operating Systems (Write Entire) and each time my idle goes to hell, stalls if I try to move, etc. The first time idle came back to normal within 30min of driving, but when I flashed back to my normal OS, same thing happened but it's taking longer to return to normal... currently it tends to hang lower than normal but is getting better.

Never have that problem just writing entire with the same OS.

I guess my point is, dont make changes yet unless you've put some driving and idle time on it or you will be chasing your tail.

[30thta436]

This thing wont even idle sitting there.

I think this is an unlocked tune.

[5FDP]

Have you tried settings the MAF fail high to 2hz and the low fail to 1hz, then settings the 3 MAF dtc's to MIL on first error. That way it reverts straight to speed density.

[Bill@HPTuners]

^ looks like you tried failing the maf but then left the dtc's so it won't fail, the computer is not understandingz.

[10_SS]

Have you tried settings the MAF fail high to 2hz and the low fail to 1hz, then settings the 3 MAF dtc's to MIL on first error. That way it reverts straight to speed density.

you need to change the timer on that failure as well... I used to get starts then stalls until MAF failed, change the timer to 0s and it went away. But nobody ever mentions the timer.

Test Engine Run Time = 1s stock, so it wont start the test until 1 full second of engine running, then Test Enable Delay is also 1s that that's 2 seconds it tries to use the MAF. If it's plugged in and calibrated usually you dont notice it, but if it's unplugged or not properly calibrated it causes problems. Best to set those to 0s or 0.1s I dont think it matters.

[30thta436]

Changed MAF Fail High to 2, Low to 1 and changed the DTCs to set on first error. Same issue.

[30thta436]

you need to change the timer on that failure as well... I used to get starts then stalls until MAF failed, change the timer to 0s and it went away. But nobody ever mentions the timer.

I'm getting the MAF to fail. Check Engine light is on and that is my only DTC

[10_SS]

I'm getting the MAF to fail. Check Engine light is on and that is my only DTC

I know your getting it to fail, 2 seconds after you start without it failed (usually the first time). So if your making changes and reset the DTC somehow, this 2 sec is a long time at startup especially if you unplug it or mess up calibration to make sure it's failed.

[30thta436]

I know your getting it to fail, 2 seconds after you start without it failed (usually the first time). So if your making changes and reset the DTC somehow, this 2 sec is a long time at startup especially if you unplug it or mess up calibration to make sure it's failed.

ERT set to 0. No change

Would it be anything from my injector scaling? 1/2 Flow Rate, 1/2 IVT Terms, 2X Stoich? anything else I need to do?

[GHuggins]

What map sensor do you have? Willing to bet it's probably wrong in the tune from the looks of it - from the log it looks like a fueling issue...

[30thta436]

2bar MAP. GM 12615136. The car measured boost with the MAF enabled.

[Lakegoat]

MAP sensor offset should be 8.00---but that will not solve all of the problem

[30thta436]

What map sensor do you have? Willing to bet it's probably wrong in the tune from the looks of it - from the log it looks like a fueling issue...

Any suggestions on which direction to go?

MAP sensor offset should be 8.00---but that will not solve all of the problem

I'm open to any and all ideas. I have tried everything I know to do and it still won't idle on it's own.

[GHuggins]

OK, just to get it running - I don't know why, but some do this for the first time or two going SD even with the timers set low... Put back into MAF mode - fire it up and let it get to temp / 0 out and correct your intake temp sensor biasing since it has been relocated to the blower - use ZL1 settings of 0 in main table and 1's in multiplier table / after it gets to temp - fail the MAF and see if it will now run - if not look at your min throttle allowances for failed MAF in idle airflow section... It should fire and idle then...

[Dragit]

Sorry to revive a dead thread... But was a solution to this ever found?

I too have a 07 Silverado with a e38 ecm. Though mine is just a cammed 4.8..

Issue Im having is failing the MAF.. by either pulling the wire... failing it in the tune... or a combination of the two.. will cause the ecm to completely ignore the idle tables. And i mean all of them. The min idle airflow, the desired idle speed, the max idle area, etc etc etc. No change you make to these tables will make any difference as they are being ignored. It will try to idle at 500 rpms using the actual base spark tables. NOT the idle spark table.

I actually confirmed this logging timing, then changing the values in the high and low octane tables... then logging the timing seeing the change i made in the main spark tables. Put the MAF back in play and all the idle tables come back online. Weird stuff.


So issue I have is i cant fail the maf and tune the VE table. Im not really sure where to go to from here.... so curious if this was resolved!