91 GTA 5.0L problems
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Junior Member
Joined: Jun 2006
Posts: 5
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From: Arizona
Car: 91 GTA t-top
Engine: 355 TPI
Transmission: 700R4
91 GTA 5.0L problems
hey everyone,
here's my issues, the car used to run decent but wouldn't shift into 3rd or 4th(auto/overdrive) and hot it wouldn't shift into 2nd. got a new tarnny for it and now it shifts not a problem. everyting was good for 3 days then I added oil and a pcv valve. this car burns oil not sure how much since I haven't been able to drive it much. but after that when I took it out for a spin it started off good then just started running weaker and weaker, like at full throttle in 2nd it was going 30MPH at 1500RPMs.
it also has way too much fuel vapor pressure in the tank, the vacumm switch by the canister is working properly, I'm not sure about the electric switch on the canister itself. right now I just run it with the cap loose. It does have a fuel leak, i think from tank, at the high pressure fuel leaks from front middle of tank, a little to passenger side, drips onto muffler, I know not good at all, but it is only at that very high pressure, cap loose and it doesn't happen.
and yet another issue, the car has almost or no oil pressure on factory gauge until 2000RPMs it is full on oil, is this normal?
everytime now after a few seconds sometimes upto a minute it will run fine but then it craps out. here is a list of things I've checked/replaced.
the passenger side valve cover has one bolts in middle of cover missing, not the bolts that hold it to the head but the ones in the very middle of the cover.
alternator replaced
plugs and wires replaced. They are correct, double checked.
cap and rotor replaced.
air filter replaced.
oil and filter replaced.
transmission replaced(done at a shop)
radiator hoses replaced
some vacumm lines replaced, I know they are hooked up correct.
block and radiator flushed(had very rusty looking water)
thermostat replaced with a 195.
fuel filter replaced.
oxygen sensor to be replaced on monday
exhaust flange gaskets on moday also.
i'm waiting to change the oxygen sensor until I get the exhaust gaskets, the drivers side(side with oxy sensor) is blown completely, so I want to replace that then the oxy.
that is the order I did everything too, there was a break of about 2 weeks before the tranny was done, then a week or so after the tranny was done before more work was done.
tps sensor checked(0.58-4.08 volts) good?
fuel pressure was 44psi.
compression was about 150 on most cylinders, the front two were 80ish, and the third from front on drivers side was 180.
the vacumm was checked on manifold to be a shaky 4-5 jumping to 2PSI-0. and at 3000RPM it was 9FT-LBs.
if anybody could list what values all the sensors are suppose to give that would be cool, my book doesn't say other then the oxy should not be checked with a volt meter, well duh.
I think that covers it.
would like to get it drivable at least, I know a whole engine job needs to be done, but I also need it driveable until that time. Thank you for helping.
edit: I've checked the codes on nothing but 12 system acknowledgement
I also played with my MAP sensor and with it disconnected I get a code(of course) but it runs better, knocks and pings alot but can run. so maybe the MAP bad or could it be right and the the vacumm in the manifold be bad?
here's my issues, the car used to run decent but wouldn't shift into 3rd or 4th(auto/overdrive) and hot it wouldn't shift into 2nd. got a new tarnny for it and now it shifts not a problem. everyting was good for 3 days then I added oil and a pcv valve. this car burns oil not sure how much since I haven't been able to drive it much. but after that when I took it out for a spin it started off good then just started running weaker and weaker, like at full throttle in 2nd it was going 30MPH at 1500RPMs.
it also has way too much fuel vapor pressure in the tank, the vacumm switch by the canister is working properly, I'm not sure about the electric switch on the canister itself. right now I just run it with the cap loose. It does have a fuel leak, i think from tank, at the high pressure fuel leaks from front middle of tank, a little to passenger side, drips onto muffler, I know not good at all, but it is only at that very high pressure, cap loose and it doesn't happen.
and yet another issue, the car has almost or no oil pressure on factory gauge until 2000RPMs it is full on oil, is this normal?
everytime now after a few seconds sometimes upto a minute it will run fine but then it craps out. here is a list of things I've checked/replaced.
the passenger side valve cover has one bolts in middle of cover missing, not the bolts that hold it to the head but the ones in the very middle of the cover.
alternator replaced
plugs and wires replaced. They are correct, double checked.
cap and rotor replaced.
air filter replaced.
oil and filter replaced.
transmission replaced(done at a shop)
radiator hoses replaced
some vacumm lines replaced, I know they are hooked up correct.
block and radiator flushed(had very rusty looking water)
thermostat replaced with a 195.
fuel filter replaced.
oxygen sensor to be replaced on monday
exhaust flange gaskets on moday also.
i'm waiting to change the oxygen sensor until I get the exhaust gaskets, the drivers side(side with oxy sensor) is blown completely, so I want to replace that then the oxy.
that is the order I did everything too, there was a break of about 2 weeks before the tranny was done, then a week or so after the tranny was done before more work was done.
tps sensor checked(0.58-4.08 volts) good?
fuel pressure was 44psi.
compression was about 150 on most cylinders, the front two were 80ish, and the third from front on drivers side was 180.
the vacumm was checked on manifold to be a shaky 4-5 jumping to 2PSI-0. and at 3000RPM it was 9FT-LBs.
if anybody could list what values all the sensors are suppose to give that would be cool, my book doesn't say other then the oxy should not be checked with a volt meter, well duh.
I think that covers it.
would like to get it drivable at least, I know a whole engine job needs to be done, but I also need it driveable until that time. Thank you for helping.
edit: I've checked the codes on nothing but 12 system acknowledgement
I also played with my MAP sensor and with it disconnected I get a code(of course) but it runs better, knocks and pings alot but can run. so maybe the MAP bad or could it be right and the the vacumm in the manifold be bad?
Last edited by Mjaz; Jul 23, 2006 at 12:03 AM.
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