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Discussion Starter · #1 ·
I had to go into work today because of an escaped prisoner. So on my way home I decided it was time to plug in AutoTAP and pull some data related to Torque Management. AutoTAP is an AWESOME program that is very customizable. So anyway, here it goes:


Have you ever wondered why your GM Truck seems to run out of power as it revs?

Have you ever wondered why your truck seems so slow after downshifting during wide open acceleration?

What happens when I hit my speed limiter on an 03-04 GM truck?

PAY CLOSE ATTENTION TO IGNITION TIMING ADVANCE

Abuse Mode
Simple Idle-Everything look great


Wide open from a stop. Timing is pulled WAY back


Still Negative Timing


Finally, A little positive timing


Peak timing of this run
 

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Discussion Starter · #2 ·
Power Loss: Timing is being pulled again.


Say good bye to any positive timing just before the shift to 2nd


Positive acceleration is back
 

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Discussion Starter · #3 ·
Top speed run


What is going on? Pedal is to the floor but the PCM is only allowing 50%


99MPH Limit. Foot is still stomped on the gas. Electronic throttling at its best


What it looks like at 75MPH with cruise control


There you have it. All the reasons you need to get rid of Torque Management.
 

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positive 34 degrees timing when shifting then drop to 28 degrees timing then back up to 34. that is what my truck does according to my predator and allen's autotap.
 

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HOT AIR BALLOON OWNER
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I'll be damned, the TPS is open. :pow: I could have sworn it'd be closed.

But look at the timing...or lack there of. lol That neg timing at low RPM is the Abuse Mode.
 

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Discussion Starter · #9 ·
Thanks guys,
I appologize for not adding this:

I compiled this data using my new 2004 2500HD, 6.0, 4.10, 4L80-E.
I have been too lazy to update my sig. I assumed since I have Electronic Throttle Control I would see the computer controlling the throttle blade in first gear. But I didn't. Either the data update through he ODB2 bus is too slow or my laptop is too slow (possible). I may do another run with only Ignition Timing Advanced to see if I can get quicker data. The next thing is I expected around -30 degrees to be pulled from a WOT run from a dead stop. Again either the bus is too slow, the laptop is too slow OR Torque Management, when used with the 4L80-E, is not as aggressive as it would be on the venerable 1/2 ton 4L60-E transmission.

I did note 2 things:

1. The data I see is not the result of change, but the PCM requesting a change. For instance, AutoTAP will show I just shifted into 2nd gear, whereas I know I am still in first. The OBD2 bus must only send what the computer is REQUESTING of the components, not if it has been done.

2. The GM OBD2 system has 2 options for Throttle Angle. The first, as you can see, is Throttle Position Angle. This is displayed in %, but is based on voltage I think from 0.1-5 Volts. This shows the exact position of the Throttle Body in the Intake. The next is Throttle Position Desired Angle. I assumed this was the accelerator pedal. However, after reviewing the posted data labeled Top Speed Run I realize this only shows what the PCM is REQUESTING the Throttle Blade to be at. I had it floored, but the PCM was showing both figures to be 58% at 94 MPH all the way to 99MPH. I see no way to display what the driver actually wants it to be at.

For the members that gotta see graphs. Take a look.
Ignore the last frame of data in each graph because that is where I stopped the graph.

Dead Stop to 4700 RPM. 1st gear-Timing falls to pieces


1st-to-2nd upshift. ~5000 RPM in 1st gear. Again Timing drops into the negative


There you have it. Total loss of HP and Torque
 

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HOT AIR BALLOON OWNER
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Ah yes, you do have a 4L80E also.

I do recall someone telling me that despite what it shows, it's only what you're looking for on ATAP. Like my A/F was showing like 12.5:1 WOT where in reality it was closer to 11.8:1 when I first had it tuned.

I still think the TPS closes for some reason. Despite your foot being to the floor and ATAP showing 99.6% but that's what your foot wants not what the PCM is allowing.

EFI-Live apparently shows complete real time stats. May be worth a run if someone local has it.

I was having 40° pulled total, so I was supposed to be around 36-40° at the 6000rpm mark and I was like you are at like -8-10° instead.
 

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Discussion Starter · #11 ·
I own EFILive also and it "appears" to work like AutoTAP, just better looking and allows me to manipulate the engine. They use the same cable and it is the cable that can read the bus. I am pretty confident what I see from both TPS settings, one is the exact voltage (measured in %) from the sensor and the other is from the PCM's request.

You may be correct about the Throttle Blade closing though. Either the Bus was too slow,or my Laptop was too slow. I am gonna try another run with just TPS and another with just Ignition. If my laptop is to slow, running 2 runs with just those will be enough.

Another thing is on my 1999 NBS I can remember the 1st-2nd upshift being nasty. If I add your statement about the timing you see being pulled on your truck I am thinking that the 1/2 Ton Torque Management is even MORE aggressive than the 3/4 ton. I feel you are correct Hit Man. The 4L60-E has a 3.06:1 First Gear Ratio. That is one hell of a jolt from a dead stop to WOT. And the transition from 3.06:1 to 1.63:1 (2nd gear) is even more extreme. I would feel TM is more aggressive which is why you were seeing more timing being pulled. My GF's dad has an '03 1500 5.3/4L60-E Z-71. I am gonna try his and pull some data for a comparison.

I am having fun with this.
 

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HOT AIR BALLOON OWNER
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Yeah also I used to own a '99 NBS, it was a turd. Those had many, many PCM problems. Jared on here (99silver5.3) swapped in an '02 PCM in place of his '99 PCM and despite the Battery light being on his truck runs WAY better.

Usually they have False KR and other problems like low and slow timing advance tables too. My '01 when stock would run circles around my mild mod'd '99. That's how vast the difference is between them!

It wouldn't suprise me if TqMgt tables are different between the 1/2 ton and 3/4 ton but I'd like to see if the entire PCM setup is actually different for the timing area.

Do post up that EFI Live log when you get it with the TPS and Timing, I'm anxious to know if I'm crazy or not! :anitoof:
 

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Burning Rubber
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Hit Man X said:
Yeah also I used to own a '99 NBS, it was a turd. Those had many, many PCM problems. Jared on here (99silver5.3) swapped in an '02 PCM in place of his '99 PCM and despite the Battery light being on his truck runs WAY better.

Usually they have False KR and other problems like low and slow timing advance tables too. My '01 when stock would run circles around my mild mod'd '99. That's how vast the difference is between them!

It wouldn't suprise me if TqMgt tables are different between the 1/2 ton and 3/4 ton but I'd like to see if the entire PCM setup is actually different for the timing area.

Do post up that EFI Live log when you get it with the TPS and Timing, I'm anxious to know if I'm crazy or not! :anitoof:


My 99 is a complete turd as well. The engine is completely stong and flawless and I have a brand new built tranny.... The TM simply reems this truck. I doubt swapping a newer year PCM would be good for the truck, or the correct way to do it. A simple tune on any year PCM will make a world of difference on these motors. I am going to be putting either a PCM 4 less tune, or LS! edit in my truck when the gears and locker go in.
 

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HOT AIR BALLOON OWNER
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Chris99GMC said:
My 99 is a complete turd as well. The engine is completely stong and flawless and I have a brand new built tranny.... The TM simply reems this truck. I doubt swapping a newer year PCM would be good for the truck, or the correct way to do it. A simple tune on any year PCM will make a world of difference on these motors. I am going to be putting either a PCM 4 less tune, or LS! edit in my truck when the gears and locker go in.


Don't forget you probably have that stupid 8° false KR too!
 

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Burning Rubber
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Hit Man X said:
Don't forget you probably have that stupid 8° false KR too!

:think: ... not too sure what you mean by KR
 

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kr===knock retard. in 1999 there was always problems with the torque management seeing false kr. this is what has been found to hurt performance. with a nelson tune you get a reflash with all the latest updates and a bad ass tune which will take care of the 99 ghost kr.
 

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HOT AIR BALLOON OWNER
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Chris99GMC said:
:think: ... not too sure what you mean by KR


Just be certain you have it, should be around 8°. Get a base 87 oct factory tune in your truck and put 93 oct in it, in theory no detonation should occur...of you have KR. Try some 97+ oct (make your own with Xylene or Toulene ~5:1 ratio I believe) then you will know if it's fake.

There is no way you'll knock with 97 oct fuel on a stock timing/fuel map. You may also have to desensitize the knock sensors. 99silver5.3 did on his and made it run all sorts of better apparently.

1999 timing maps are also weaker to begin with than the '01+.
 

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So basically, when i order my tune this fall, am I gonna notice a HELL of a difference on my 99 vs. the way it performs now? I don't think its too bad, other than the TQM being gay. Reason why I'm askin is because I'm already anxious to get it...just wondering how happy I'm going to be :rocking:
 
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