Shifting Blues
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Ok, I hear this issue all the time, its time for a sticky.
Guys/Gals with automatic cars listen up!
When you switch to a nice high stall torqe converter, the PCM can no longer use its default program to determine engine misfire. Here is the reason: The corque converter is part of the rotating mass of the engine's rotating assembly. When you reduce the wieght of the converter you are reducing the amount of Flywheel effect. The computer's stock tune is very sensitive to this rotating mass. Therefore the computer can no longer accuratly read engine misfire.
The computer has a logic routine that has certain perameters to be met before the computer locks the TC. They are (as far as I can tell):
1. Throttle position vs. MPH (normal cruise tables)
2. Engine coolant temperature > ???F (not accessable in edit)
3. > 40-50 misfires per 200 revolutions (not accessable in edit)
4. TPS = WOT
After these parameters are met, the computer waits 4-5 seconds then locks the converter.
So, for this thread the number three is the issue. Now keep in mind this is NOT code based. If you disable code PO300, this problem still exists, cause it is only looking at the current misfire count. there are only two ways (in Edit) to prevent these faulse misfires from affecting the TC lockup:
1. Set the misfire activation temperatures to 141 and deactivaion temps to 142. This is the easiest method, but its drawback is the complete disabling of the misfire detection/trouble shooting.
2. This method is more trial and error, it involves adusting the time delays of the misfire program in edit for the various ranges of detection. I personally don't use this method, so someone who does feel free to chime in here.
After disabling the misfire detection, barring any mechanical failures, the person should have little to no issues with TC lockup. I hope this helps, please feel free to direct people to this thread if you see they are haveing a TC lock up issue after installing a new torque converter.
Ryan K.
LS1 Edit Beta Tester
Basically Go get a tune. Hope this helps.
I'm making some assumptions here, but it sounds like you went from stock convertor & tranny to a vig 3200, still have stock programming and it sounds like you just need someone to do some tuning to adjust shift points, lockup points, etc. Giving us more info though will certainly be helpful.
Also, when you say she locks about 35mph, do you have the shifter in 3rd (D on the pontiac) or D (OD on the pontiac)? I have mine tuned so she'll lock at ~35-37 mph in 3rd gear (so she's just over 1500 rpms) and then kick the shifter up to 4th once I know I'm over my 4th lockup point (~50mph). For me, it works better doing it that way with rush hour traffic on 95..helps keep the heat down and saves some on gas since the convertor is locked more. (I also have a built tranny, I don't know about doing that on a totally stock one..)
One final thing, just out of curiosity, I see you mention 95, what state are you in?
Is this something that could cause transmission problems and therefore I should do IMMEDIATELY?
I can't tell you guys how thankful I am for your help!
Yeah, I am very thankful for having a wife that enjoys the sport with me. My best time in the 1/4 is 12.8 with a 1.78 60 ft on regular nitto 555's. Oh yeah, the car is a 2000 ws6 a4. These are all the mods I know of on the car. Thanks for all the help. One more thing, in 3rd the thing locks up at like 25, but the rest of what I listed was in od.On a side note, kenafin, did you used to live in woodbridge? I have seen you a few times in the T/A and I have a friend named Jonathon that used to know you, if you're the same person. Thanks again for all the help.
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