What you cause my transmission to sometime behave like its shifting into third and fourth at to low an RPM consequently lugging the engine.
There could be a few causes but do you have a 3800SC swap??? If so was the PCM programmed for tire size/transmission settings?
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
What you cause my transmission to sometime behave like its shifting into third and fourth at to low an RPM consequently lugging the engine.
Need more info. Shift tables are governed by TPS % and vehicle speed. At very low throttle opening, it is possible the transmission may upshift into a higher gear at lower speeds. You may also have the TCC engaging earlier than anticipated which would further drag down engine RPM.
Bottom line is you are going to need to connect a scan tool to the PCM so you can view live scan data showing throttle opening % and vehicle speed, as well as current trans gear and TCC lock status info. With this data, I will be able to look at the tune I made for you and determine if something is wrong or not.
-ryan
------------------ More is more. Less is not enough. Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com
Neither of my scan tools show FCC. Until I get one I have a couple of things to point out. First, when shifting into second under heavy load the transmission has a stutter at the shift point and my not shift. Second, when cruising at highway speed thetranny slips just a little like one or two hundred rpm for a very short time and then catches over and over. Third, the time between shifts seem rather long. And fourth, the engine sometimes shift into drive and over drive and seemingly lugs the motor. If its the FCC solenoid or something requiring tranny work do I have to drop the cradle? Can I remove the tranny from the car while mounted up in the car?
Neither of my scan tools show FCC. Until I get one I have a couple of things to point out.
First, when shifting into second under heavy load the transmission has a stutter at the shift point and my not shift.
Sounds like an internal transmission problem (ie: worn out clutch packs, failing pressure control solenoid, etc). Scan data showing PCS actual amperage at the shift and what the recorded shift time is might be helpful.
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Second, when cruising at highway speed thetranny slips just a little like one or two hundred rpm for a very short time and then catches over and over.
The TCC is designed to slip a little bit at all times while it is applied in these applications. When you are cruising at a steady speed, the actual slip RPM of the TCC clutch should be around 20 rpm or so. If you apply a little throttle, the slippage may flare up to 100-200 rpm but should quickly come back down as the PCM applies more TCC pressure. THIS IS NORMAL OPERATION.
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Third, the time between shifts seem rather long.
Again, sounds like an internal transmission problem (ie: worn out clutch packs, failing pressure control solenoid, etc). Scan data showing PCS actual amperage at the shift and what the recorded shift time is might be helpful.
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And fourth, the engine sometimes shift into drive and over drive and seemingly lugs the motor. If its the FCC solenoid or something requiring tranny work do I have to drop the cradle? Can I remove the tranny from the car while mounted up in the car?
What you are describing here might actually be normal operation that would occur in a stock vehicle. BUT I need to know exact MPH and TPS% values when these shifts are occurring so I can determine if there is a malfunction or not. If this does turn out to be normal operation and you simply don't like it, we can change the tune to delay these upshifts a bit so they don't occur "so early".
Well seen as how I'm going to wind up pulling the tranny and sending it to zzp i might as well get my blower ported and upgrade the rockers. Do I need an intercooler too? How easy are them cams?
Well seen as how I'm going to wind up pulling the tranny and sending it to zzp i might as well get my blower ported and upgrade the rockers. Do I need an intercooler too? How easy are them cams?
Only code I get is 131 O2 sensor slow. The fluid is about three months old and looks new. Yesterday I drove it 20 miles normal driving. I only got on it enough to get 4psi of boost. The transmission didn't act up at all so it apparently doesn't act upmall the time. I doubt it would have shifted correctly from first to second if I had really got on it.
Only code I get is 131 O2 sensor slow. The fluid is about three months old and looks new. Yesterday I drove it 20 miles normal driving. I only got on it enough to get 4psi of boost. The transmission didn't act up at all so it apparently doesn't act upmall the time. I doubt it would have shifted correctly from first to second if I had really got on it.
Could be a PCS issue. I've seen them cause intermittent problems just before they totally fail. Unfortunately, the side cover has to come off to access it, which can rarely be done in the car.
But then again, it could be a lot of other things. Without seeing some detailed scan data, I can't offer a better diagnosis.
