PCM Pulling Timing When Accelerating

[TXjeepTJ]

Hi,

I'm having an issue when I give a good amount of throttle, the PCM starts pulling timing - and the car barely wants to accelerate.

What would cause timing to be pulled like that? IAT was 80 degrees F, so I doubt that was the issue.

I'm trying to dial in my VE table, so that is what the tune is setup for

Timing.JPG

This is a 6.0L LQ4 DBW 24x - only mods are a cam (232/240 .595/.608 115) and long tube headers

[nkautz]

Go to your high octane spark table and select the entire row @ 0.72 and copy. Now select entire row 1.20 and click paste. Now interpolate between those two rows. Now copy high octane spark table to low octane spark table. Flash that tune and try doing a pull.

Always watch for KR in the scanner.

[POWERZONE]

First go to VCM scanner,while you are tuning VE verfify that the MAF is not reading, once you verify this, go to the primary table and delete the pid mass air flow(sae)(When you are ready to tune the MAF, you can set this pid back in). Then go back out and log. This will give you the correct air mass readings so you can read and see accurately on your histograms where the retarding is occurring.

Once you notice where its retarding. Go back and look at your high octane spark table. If the timing is still retarded below those values then you know some other table is pulling timing.

But just roughly looking at your tune>
You still have a good amount of torque management active.
Several of your tables in torque management under engine need to be addressed.

[TXjeepTJ]

First go to VCM scanner,while you are tuning VE verfify that the MAF is not reading, once you verify this, go to the primary table and delete the pid mass air flow(sae)(When you are ready to tune the MAF, you can set this pid back in). Then go back out and log. This will give you the correct air mass readings so you can read and see accurately on your histograms where the retarding is occurring.

Once you notice where its retarding. Go back and look at your high octane spark table. If the timing is still retarded below those values then you know some other table is pulling timing.

But just roughly looking at your tune>
You still have a good amount of torque management active.
Several of your tables in torque management under engine need to be addressed.

Thanks for the response. I do not have a MAF on the vehicle (will be going SD Closed loop), so there shouldn't be any info going into the pcm from the MAF. I will do what you said though.

Yeah, I haven't really messed with the transmission besides adjusting the TCC lockup tables since the transmission does have a 3k rpm stall (forgot to state that above). I'll do this tonight also, thanks for pointing it out! I would have just forgotten about it

[POWERZONE]

Thanks for the response. I do not have a MAF on the vehicle (will be going SD Closed loop), so there shouldn't be any info going into the pcm from the MAF. I will do what you said though.

Yeah, I haven't really messed with the transmission besides adjusting the TCC lockup tables since the transmission does have a 3k rpm stall (forgot to state that above). I'll do this tonight also, thanks for pointing it out! I would have just forgotten about it

Well if you are leaving it SD, you can just delete that MAF(sae) pid so you can see your spark and retard spark histograms read accurately.

The torque management tables I am talking about are under the engine tab.

[TXjeepTJ]

Post TQ Mngmnt.hpl
Chevelle Tuned V2.hpt
Tuning Setup_WideBand.cfg

Files are above, not sure why it attached them that way - hover over it and click

Ok, I adjusted the torque management thinking that is why the timing was dropping - went and logged and it was still dropping. I then compared the recorded Main Spark vs the spark table in my tune and they were pretty much the same numbers where it drops. So I guess I need to add timing? Tuning spark is one of those things I can't really find a good method on tuning. I attached my new tune and new log.

I got knock retard the first time I got a little on it. The second time there was no knock retard, but the spark was 2 degrees below what the tune has in it. The tunes values are still really low it seems like - is that just how it's supposed to be?

[POWERZONE]

Just roughly looking at your log, your commanded PE is 14.58 at WOT.

Before adding any timing I would address the PE and AFR at WOT issues first. You look to be commanding 14+ at wot and your lamda is 14 to 15+ at 100% TPS.

Try 12.3 to 12.5 as a base line AFR.

Too add:
Go to engine>fuel> power enrich:
Your TPS% cold is 90%= try to scale it starting at 50% in lower rpms scaling to a lower number as rpm increases with a final of at least 20 at higher rpm.
Your PE delay is 5500= change to 0
Your enable torque is 100%= set it to 0
Set your enrichment ramp in to at least 1.5 or 2.0

Make sure to log AFR commanded vs. AFR error and adjust accordingly.

Once you get the AFR/PE under control then you can add timing but be careful.

[nkautz]

It's probably torque management or traction control. Definitely get it coming into fuel sooner with the PE changes. Good point Powerzone. I can't believe the wot spark is so low in that tune for a non-boosted car.

[TXjeepTJ]

Thanks so much for your help Powerzone!

Do I also set the PE Delay time to 0 seconds?

[TXjeepTJ]

It's probably torque management or traction control. Definitely get it coming into fuel sooner with the PE changes. Good point Powerzone. I can't believe the wot spark is so low in that tune for a non-boosted car.

Just saw in my torque management table that traction control was not disabled and that could be pulling timing. I set it all to zero! Thanks!

[nkautz]

Pulled this from a post by RWTD , all credit goes to him:


"Okay, to COMPLETELY remove torque management, follow these instructions below. Keep in mind, zeroing out the torque management on the trans will likely result in a sloppy 1-2 shift at WOT. Oddly enough, some of the newer classic Silverado/Sierra trucks already have the Torque Reduction zeroed out on non-tow/haul mode. Also, yhere is some redundancy in doing some of these below, but I listed everything, regardless.

Engine, Torque Management, General:

Maximum Torque
RPM vs. Gear - Max out
vs. RPM - Max out

Max Torque
Max Torque - Max to 640
Tip In Torque - Max out
Trans Input Max - Max out
Trans Output Max - Max out
Front Axle Max - Max out
Front Propshaft Max - Max out
Rear Axle Max - Max out
Rear Propshaft Max - Max out

ETC Limits
ETC TPS Max - Max out

Spark Retard
vs. Torque Reduction - Zero out

Torque Loss %
vs. Spark Retard - Zero out

Engine, Torque Management, Abuse:

Drivetrain Abuse
RPM > - Max out
Speed < - Zero out
timer vs. Trans Temp - Zero out

Trans, Torque Management:

Abuse Mode
Enabled - Set to Disabled
RPM - Max out
TPS - Max out
Speed - Zero out
Torque Reduction - Zero out

Torque Reduction
Normal - Zero out
Performance (aka Tow/Haul mode) - Zero out "

[POWERZONE]

Thanks so much for your help Powerzone!

Do I also set the PE Delay time to 0 seconds?

Yes, for your case, there is no need for a time delay.

Remember tuning is something that you get better at with the more chair time you get.

Just take baby steps so you don't blow anything up. And if you are unsure, do not be scared to ask first. There are no stupid questions in tuning.

[POWERZONE]

Just saw in my torque management table that traction control was not disabled and that could be pulling timing. I set it all to zero! Thanks!

Since you have it in a Chevelle I assume from the title of your file, you can disable the traction control. I assume you are not running any type of traction control system either.

[TXjeepTJ]

Since you have it in a Chevelle I assume from the title of your file, you can disable the traction control. I assume you are not running any type of traction control system either.

Correct. I disabled all traction control, also changed the PE settings. Took it for a test drive and it is now going into PE mode - but I am getting very high lean spikes, I think it was due to gasoline sloshing in the tank when accelerating.. Will have to top it off and try again

[nkautz]

Put up a log of the lean spikes. Might just be DFCO

[Hardluck29]

This is a really old thread but did his timing Drop Problem ever get solved? I have the same problem but all my torque management is disabled. Or so I thought.

[55Belair]

You should probably post your tune and a log file as well as a short description of your engine/trans combo and any modifications. I'm interested in seeing what the experts come up with as I'm having the same issues. Whatever it is, it seems to be quite common.