At high rpm my 86 gn stumbles, falls off, won't shift until you let off a little, I have replaced nearly the whole car and can't figure it out, New stuff so far includes: Fuel pump, regulator, injectors, coils, module, every sensor except knock, computer, chip,etc, the last thing strange enough made a big difference but didn't completely fix it was the alternator. It still does it, falls on its face at high rpm, pings a little and won't shift until you let off a little. I tried letting out the kickdown cable some and that doesn't help. I don't know where to go. Can anyone help? Please?
What are your tps settings at key on position and key on petal to the floor.
Frank
A couple other thoughts ...
- TV cable is stretched (set too tight)
- Valve springs are shot (very common, even on low mileage cars...usually limits RPM)
- TV sticking in the valvebody
- Too much line pressure in trans (sticking regulator?)
- Fuel pressure falling off (dying pump)
- Grounding problem at the back of the passenger's side head (causing voltage drops at WOT and missing
What RPM are you seeing the problem at? What's the scan tool say?
I'd have to check the tps, I dont think its a tranny problem. I just had it rebuilt last year, The rpm goes all the way red and so does the boost. I think it might be a fuel problem but I don't know. I put a pump in already and a regulator and the pressure is somewhere around 50 something if I remember right. But why is the boost going all the way red with a stock turbo and waste gate? Is the waste gate bad and thats whats happening? Too much boost and not enough fuel?
Forget the factory boost gauge and tach as a reference. As ken mentioned it's best to have
a scan tool. If you don't you at least need a
boost gauge that reads 30 psi and a knock gauge.
You mentioned stock wastegate if it is stock you
need an adjustable wastegate. What type of pump,
regulator and inj's did you install.
I didn't want to waste alot of money cause I would like to build it in the future so the pump is just an ac delco stock pump, the regulator is off a turbo t/a, I was told it had a few more pounds.? The injectors are green stripe. I will try and come up with a boost guage to see whats really going on.
I had this problem to during some 1/8 mile runs. The problem only happens during WOT runs. Any thing else is ok. Someone suggested that the TV cable isn't used for WOT and that it might be the governor.
I think i have this exact same problem right now! At high rpm's the engine sounds like it "sneezes" and wont shift till i let up a little. and now that i think of it, i began to notice it a few days after i adjusted the TPS and IAC. I will go check my TPS to see if it helps me out.
Chris, I think Shawn is right! I had the same problem a couple of years ago and thought it might of been fuel! But it's pretty obvious, no sensor in the car will prevent the tranny from shifting, so you have to eliminate the TPS etc.. I'm not sure whether the TV cable is or is not used during WOT but from previous experience I narrowed it down to the spring on the governor had fallen off (usually when you over rev the car or worn parts). I initially just dropped the pan and reinstalled the governor spring only for it to pop off after a few (10 or so) passes. So I purchased a new governor about two years ago and has not failed me since!!!! Almost lost a money race against an Olds w/350 Chivvy motor on N.O.S. because of this darn governor :-).. GOOD LUCK..
MARIO