Commanding more timing then set in tuner?

[GeforceXtreme]

Over the weekend I licensed a friends car to start lightly tuning. Well the small changes I made to the car like the cooling fans to stay on after shutting off worked. However when i started making changes to his cruse timing something was really odd. Whatever I would set into the High Octane Spark Advanced table it would not show that during scanning. Like if I set it too 38 it would command like 46! I then proceeded to zero out the AFR Correction table thinking that was adding timing on top of the base table however it was still commanding way too much timing then what I had set in the tuner. Is there something I am missing that is adding like 8 degree's more timing on top of the base table? I checked the other tables like IAT, ECT and I don't see anywhere that it would be added that much more timing? This was even after the car was warmed up. This is a 1999 Buick Regal GS and I own a 2000 Buick Regal GS and have no problem like this.

[GeforceXtreme]

I scanned his car today with the bone stock timing tables and the highest i show in the stock table is 33*. Well I saw his car go up to like 38* and no where in the table does it read 38*?

Could there be a compatibility problem with the tuner and his car? Before with an older version of the HP tuners we were not able to license his car because of his OS ID # not being supported yet. However since the new version of the HP tuners has come out we were able to license his car. Everything else I have tuned so far like transmission settings and fan settings did work. However for some reason the set timing in his PCM is not commanding when he is driving?

I also notice that in Park his car is only command 20* timing but as soon as I put it into gear it goes to 25*?

[GeforceXtreme]

Any recommendations guys?

[Bill@HPTuners]

EGR correction probably.

[GeforceXtreme]

EGR correction probably.

So you are saying with an EGR valve operating it changes the timing of the car? So unless we remove the EGR valve the good spark table is never going to command correctly to the car? Its just odd how other w-bodies I have scanned command what that table says however this one is not?

[JerryH]

I agree with Bill, but also check out the AFR Spark table if you see this in PE mode. It can add as much as 8 degrees based on what commanded AFR it hits. This is one annoying table. I zero it out and adjust the low/high octane and max torque timing tables to compensate.

[GeforceXtreme]

I agree with Bill, but also check out the AFR Spark table if you see this in PE mode. It can add as much as 8 degrees based on what commanded AFR it hits. This is one annoying table. I zero it out and adjust the low/high octane and max torque timing tables to compensate.

When i first started tuning I left the AFR correction table stock. However when I saw the car was commanding more timing then was set I zero'ed out the AFR Correction table. However still the scanner is telling me more timing then what is in the "high octane table". This is a very odd problem. I just don't want to give his car like 38* cruise timing them all of a sudden it wants to command 48* instead. We left the spark table stock but we would like to figure this out so he can benefit from running a little more timing over stock. I will check out his bin file later to see if I can spot anything else.

[JerryH]

Look at the MBTS (Max Torque Timing for the HPT people) table... what are the values in there compared to your scan? I bet they are closer to what you are scanning.

[GeforceXtreme]

Look at the MBTS (Max Torque Timing for the HPT people) table... what are the values in there compared to your scan? I bet they are closer to what you are scanning.

I wish I could say yes however that is not the case either. I will give you an example:

During the scanning: 0.24 by 2400 = 37*
High Octane Spark Table: 0.24 by 2400 = 31*
Max Torque Timing Table: 0.24 by 2400 = 32*

So as you can see the scanned data is not the same then what is set in that table. This is even with the AFR Correction table zeroed out. I am posting his bin file and also the first scan we did of his car.

[Russ K]

Like Bill said, the EGR spark is adding to the main spark tables. Disable the EGR valve as shown.

Russ Kemp

[GeforceXtreme]

Like Bill said, the EGR spark is adding to the main spark tables. Disable the EGR valve as shown.

Russ Kemp

Is it ok to disable the EGR valve while its still attached to the motor? We don't have block off plates for the EGR valve yet. Should I disable it in the PCM and unplug in? Or can I leave the wire plugged in?

[Russ K]

Is it ok to disable the EGR valve while its still attached to the motor? We don't have block off plates for the EGR valve yet. Should I disable it in the PCM and unplug in? Or can I leave the wire plugged in?

Just disable the EGR as shown, no need to unplug the wiring or installing a block off plate.
The PCM just won't open the EGR valve, and won't use the EGR spark adder table.

I also set all EGR codes to no error reported.

Russ Kemp

[JerryH]

Disablng the EGR will render your car unable to pass an emissions test, cause a 1-2 MPG drop in mileage and increase warmup times in colder temps. Just something to consider.

Besides the EGR tables, there are at least 15-20 other timing tables that we do not have availble to us in PCM code. The real way to handle this situation would be to get access to those EGR timing tables so we could control precisely what we wanted, not just globally disale the EGR.

What is more important than racking your mind about why... is simply accept that you have this condition and compensate in the tables you do have access to so that you get the timing you want.

No big deal in the end. Final results in the real world are more important.

[00GTP]

VERY NICE POINT JERRY. Just drop the commanded spark down a few degrees and watch the pcm compensate from there

[GeforceXtreme]

I will give the EGR disable a shot next time i see the owner. Thanks guys!