fuel problem i think. TECHS: PLEASE HELP!
05-07-2008, 09:12 PM
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Car: 87' Trans Am GTA, 88' Trans Am GTA
Engine: 350 TPI
Transmission: 700R4
fuel problem i think. TECHS: PLEASE HELP!
i have a 350 tpi. The motor was bored .030 and rebuilt 7 k miles ago. This was before i bought it. Its running like crap. I need help.
Symptoms:
1) on cold start once it turns over you need to pump the gas and try to get it to about 4000 rpm and decrease it very VERY slowly till you get to idle.
2) It idles like crap. Its idleing around between 650 and 1100 in park/neutral. It idles at 600-650 in drive. The idle has like a lope/chug, and there is a constant ticking/thunking noise. I cant pinpoint where its coming from. It sounds louder on the pass side of the motor, but its loud on the driver side too. I thought it might be coming from the FPR but i couldnt tell.
3) Ocassionally the idle will drop to like 400 and try to stall in reverse or drive, in which case you have to either stomp on the gas, or throw it in neutral and give it a few revs. After that, its usually fine for a while.
4) Until its at running temp, if you give it gas from idle, theres like a 2-3 second hesitation where you can hear the TB stop sucking in air and then all the sudden pulls in air and it revs. when its warm, it only does it ocassionally.
5) I checked the fuel pressure today.
-key on, motor off= 42 psi
-key on, motor on, idle= bouncing rapidly between 32-40
i'll see what the pressure is off idle tomorrow and post it.
I think my FPR is bad, but i'm not sure. At this point i think its between a fuel problem and a vaccum problem. i'm going to try to get a sound clip of it running and post the link up. I cant do a vid because my camera has horrible sound quality. Any help, suggestions, or thoughts are GREATLY appreciated.
Thanks
Symptoms:
1) on cold start once it turns over you need to pump the gas and try to get it to about 4000 rpm and decrease it very VERY slowly till you get to idle.
2) It idles like crap. Its idleing around between 650 and 1100 in park/neutral. It idles at 600-650 in drive. The idle has like a lope/chug, and there is a constant ticking/thunking noise. I cant pinpoint where its coming from. It sounds louder on the pass side of the motor, but its loud on the driver side too. I thought it might be coming from the FPR but i couldnt tell.
3) Ocassionally the idle will drop to like 400 and try to stall in reverse or drive, in which case you have to either stomp on the gas, or throw it in neutral and give it a few revs. After that, its usually fine for a while.
4) Until its at running temp, if you give it gas from idle, theres like a 2-3 second hesitation where you can hear the TB stop sucking in air and then all the sudden pulls in air and it revs. when its warm, it only does it ocassionally.
5) I checked the fuel pressure today.
-key on, motor off= 42 psi
-key on, motor on, idle= bouncing rapidly between 32-40
i'll see what the pressure is off idle tomorrow and post it.
I think my FPR is bad, but i'm not sure. At this point i think its between a fuel problem and a vaccum problem. i'm going to try to get a sound clip of it running and post the link up. I cant do a vid because my camera has horrible sound quality. Any help, suggestions, or thoughts are GREATLY appreciated.
Thanks
05-08-2008, 04:59 PM
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Car: 91 formula ws6
Engine: 1 peice roller scat 383 4 BOLT!!
Transmission: 5 speed
Axle/Gears: 3.42
Re: fuel problem i think. TECHS: PLEASE HELP!
sounds like fuel , and sounds like you know what your taliing about.
it also kind of sounds like tps
or IAC
it also kind of sounds like tps
or IAC
05-09-2008, 11:36 PM
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Car: 87' Trans Am GTA, 88' Trans Am GTA
Engine: 350 TPI
Transmission: 700R4
Re: fuel problem i think. TECHS: PLEASE HELP!
i tried running it with the tps disconnected. The idle sounded like it cleaned up a little bit but not much at all. I checked the fuel pressure again today.
Idle: rapid bounce between 35-38
2500 rpm: 40
3500: 36
4500: 42
As soon as you hit the gas from idle it drops to 30 before it goes to the psi stated above. She hates me. :-(
Idle: rapid bounce between 35-38
2500 rpm: 40
3500: 36
4500: 42
As soon as you hit the gas from idle it drops to 30 before it goes to the psi stated above. She hates me. :-(
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