Full line pressure with A4 SD tune

[dissonance]

Back when I was a HPT customer the only way I knew to fix the problem, was to send the bin in and have them "fix" it.

do you still have these bin files? before and after the work... should be easy to track down if you do.

[Black02SS]

For what it is worth went to {C6001} Engine DTC Processing Enablers and I changed P0101, P0102, and P0103 to "X:Not Reported" from “B: 2 Trips, Emissions Related” and the car would not run. It would crank but not start.

When that happened, more then likely the car ran super lean. What I have noticed when turning the codes to X Not Reported, the car didn't fault into Speed Density and still used the MAF table for partial fueling. I have mine in all the cars set to 1 Trip/No Mil

[Black02SS]

do you still have these bin files? before and after the work... should be easy to track down if you do.

Nope, sure don't. Lost the HD and everything on it.

[jnorris]

do you still have these bin files? before and after the work... should be easy to track down if you do.

Per gameover on LS1Tech:

"the bits i change are just the P101,P102,P103 bits."


http://www.ls1tech.com/forums/showth...=426348&page=2


John

[bink]

Per gameover on LS1Tech:

"the bits i change are just the P101,P102,P103 bits."




John

Could someone please explain this? Is he turning off DTCs or actually changing the pcm (0,1). This reminds me that I am - the analog man.


Cheers,
joel

[joecar]

I'm sorry I don't follow, please explain further...

The transmission line pressures are set by the values in {D0701} and the other tables under the “Trans Pressures”

John

Oh, I see, you monitored the pid GM.TRQENG (calculated engine torque) and used the value of this to lookup D7001 and it said around 30/35 psi.

TOL (thinking out loud):
This means calulated engine torque is around 150/170 ftlb at idle...!!!
This points to the calculated airflow being wrong (i.e. VE table or some other table is off or way off...).
Just a thought.

[Ladyredhawk]

Oh, I see, you monitored the pid GM.TRQENG (calculated engine torque) and used the value of this to lookup D7001 and it said around 30/35 psi.

TOL (thinking out loud):
This means calulated engine torque is around 150/170 ftlb at idle...!!!
This points to the calculated airflow being wrong (i.e. VE table or some other table is off or way off...).
Just a thought.

If the MAF is unplugged/disabled for SD tune, the pcm cannot get an accurate calculated engine torque. So, in SD mode how does the pcm compensate for this and figure line pressure?

[joecar]

If the MAF is unplugged/disabled for SD tune, the pcm cannot get an accurate calculated engine torque. So, in SD mode how does the pcm compensate for this and figure line pressure?

I'm not sure (...I never am any more... ), but I suppose engine torque is calculated from calculated airflow (and other things), and then PCM uses calculated torque to lookup base line pressures, and I don't know if this applies at idle.

[Blacky]

I'm not sure (...I never am any more... ), but I suppose engine torque is calculated from calculated airflow (and other things), and then PCM uses calculated torque to lookup base line pressures, and I don't know if this applies at idle.

IIRC calculated engine torque is looked up in a table that is not visible in EFILive. Maybe we need to make it visible so you can make the PCM's calculated torque value mimic "reality".

Paul

[GMPX]

A few nights ago I flashed in a SD tuning file using EFILive/AutoVE Tuning guide in my 98 Z28 with an A4 transmission and have a problem.

The PCM is commanding full transmission line pressure at all times. All shifts are very harsh. I checked the transmission DTC fault enablers for P0101, P0102, and P0103 and they are set to “No”
The Engine DTC MIL Enablers for these codes are set to “No MIL” per the EFILive/AutoVE Tuning guide.
What can I do to prevent the PCM from commanding full transmission line pressure on all but heavy/full throttle shifts?

Thanks

John

John,

Can you please send me your file?.
I'll make the change here for you to test with and if it fixes it we'll get some new 1998/1999/2000 cal files out with the fix available.

It's basically another enable/disable type table that looks to another pressure value if the DTC is set, in the 1998's the DTC's that will cause it to do that are TPS and MAF, in the 01 file I checked nothing will do it??. Thanks to all that let out some hints on what to look for, I always figured it was just the full line pressure faults causing it.

Cheers,
Ross