I still need help guys

MySCRocket1203

Registered User
hey guys im reviving an old thread cuz im still stuck ive been scouring the forunms but i seem to keep filling up my check list and nothign new has struck me yet im having taht old car bux when its heated thing going on bad mileage car dies at idle in drive and bux and bogs down miserably under boost
its a 1990 auto the anniversary package (wich i know means nothign as far as engine goes ahah)

heres what ive done. ive replaced the fuel pressure regulator i hav erebuilt the engine replaced the dis, iac, tps, coil pack, cam sensor, cranks sensor, fuel pressure regulator, temp sensor, o2 sensors, and fuel pump & filter

the only thing left to replace are knock sensor, eec, map sensor, act sensor, pcv valve, mafs, and wiring harness.

now i read that when the egine is cold it runs rich, so why does it run fine cold and not when its hot? what problem does the extra fuel coever up?

could it be my injectors, or a horrendous vaccum leak? im getting 20 vac with my car at 30 mph and my foot off the gas, i get about 17 in gear at a stop light and about 15 in park, i have a 2.5-3-2.5 exhasut with the kooks heders and i get about 11psi when the car lets me fully throttle. ive replaced the plugs and wires at the rebuld 2k a go. and when i isntalled the headers i replaced the busted ugly acdelcos that the guys rebuilt my engine put in (as a side note never go see pacific coast motor supply) with some motocrafts like what i had in before the car started running sh*tty.

none of this changed anything. my ic tubes are properly tqed and tahts the only place i could really imagine having anything likea bad leak all the vac lines behind the plenums appear to be serviceable. i need the experts out there cuz im lost the stealership said it was laternator but its pushing proper volts. so i dont know what to say about all this. have i missed anything. what more should i do to fix this
 
if it revs slow even in neutral im thinking harmonic balancer is broken and twisted but the bucking is mostly a plug or wire
 
to update i replaced the harmonic balancer last year when it shore off the car the crank was fine and didnt have problems with the car for months after htat its only been the last 6 that have been a boig pain. also the plugs and wires have been replaced checked for resistance and are all in there and there is no spark jumping that i can see. it only happens after the car comes off of its rich fuel mixture mode.
 
Throw a fuel pressure gauge on it and make sure that the pressure comes up 1 psi per psi of boost. It should be around 38-40 I think at idle.

What temp t-stat do you have in the car?
 
MySCRocket1203 said:
........ a horrendous vaccum leak? im getting 20 vac with my car at 30 mph and my foot off the gas, i get about 17 in gear at a stop light and about 15 in park.......

Check for vacuum leaks first...... When in park you should be between 18-20 at idle, and about 15 in gear. Mine goes to about 22 when moving and foot off gas.

I found the thin plastic vacuum hose that runs from the driver side of the brake master cylinder to the sc bypass valve was leaking real bad and I replaced it with regular vacuum hose. The biggest culprit for vacuum leaks are the IC tubes.

Frit
 
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ive checked the fuel pressure that seems to be consistant 1psi per psi of boost. as far as leaks how can i chekc that while the car is running will i hear it will i feel it will i see evidence of it?? also i have a 180 degree temp and as of now no coolant leaks.
 
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Spray starter fluid around the various intake lines in the engine compartment with the engine running... don't be surprised if its one of the intercooler joints. You might think that you have them sealed, but if you've never done this before, don't be surprised. ;)
 
You can also use brake cleaner to check for vac. leaks, the car will rev up a little if you spray the brake cleaner on a vac. leak.
 
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