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Car Backfiring, No power in lower RPM

Old 12-15-2011, 01:21 AM
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Car: 1987 Pontiac Trans Am
Engine: 350 Vortec
Transmission: 700R4
Axle/Gears: 3.42
Car Backfiring, No power in lower RPM

I have an 87 Trans Am with a 96 vortec 350. The engine has an edelbrock performer intake and a Jet Stage 2 Quadrajet Carb. The cam is a Comp XR270HR. The car will sometimes blow gas out of the carb. It will also sometimes not shut off after the key is turned off. Also, when the car is being driven, if it is floored from a stop or at 1st gear speeds, it stalls and the RPMs climb extremely fast intill it shifts and then it takes off. It does not do this at higher speeds. Im not sure if this is an engine, carb, or transmission problem? Any help is greatly appreciated.
Old 12-15-2011, 01:41 AM
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Car: 1984 Camaro Z28
Engine: SBC 350
Transmission: B-W T5
Re: Car Backfiring, No power in lower RPM

^ Sounds like a timing problem.
Old 12-15-2011, 01:52 AM
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Car: 1987 Pontiac Trans Am
Engine: 350 Vortec
Transmission: 700R4
Axle/Gears: 3.42
Re: Car Backfiring, No power in lower RPM

Originally Posted by seibertjd
^ Sounds like a timing problem.
That has been a thought since it has been doing this. I've timed it with a light and adjusted by feel and it hasnt changed much. It idles pretty much okay. But Im defiantly going to work on timing some more.
Old 12-15-2011, 02:00 AM
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Car: 1984 Camaro Z28
Engine: SBC 350
Transmission: B-W T5
Re: Car Backfiring, No power in lower RPM

If you have a computer controlled setup, IIRC, your sensors will have a rather notable say in your timing. When you timed it, were all your sensors hooked up? Also, have you checked the integrity of them? Just a thought
Old 12-15-2011, 02:04 AM
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Car: 1987 Pontiac Trans Am
Engine: 350 Vortec
Transmission: 700R4
Axle/Gears: 3.42
Re: Car Backfiring, No power in lower RPM

Originally Posted by seibertjd
If you have a computer controlled setup, IIRC, your sensors will have a rather notable say in your timing. When you timed it, were all your sensors hooked up? Also, have you checked the integrity of them? Just a thought
The computer and harness have been removed.
Old 12-15-2011, 02:17 AM
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Car: 1984 Camaro Z28
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Re: Car Backfiring, No power in lower RPM

Another thing to look at is your air/fuel ratio... Sometimes you can get a backfire from running too rich, and I have gotten dieseling from running too rich in the past. It could be a combination of issues. It may be also beneficial to check your plugs for fouling, smell for excess gasoline...
Old 12-15-2011, 02:49 AM
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Car: 1987 Pontiac Trans Am
Engine: 350 Vortec
Transmission: 700R4
Axle/Gears: 3.42
Re: Car Backfiring, No power in lower RPM

Originally Posted by seibertjd
Another thing to look at is your air/fuel ratio... Sometimes you can get a backfire from running too rich, and I have gotten dieseling from running too rich in the past. It could be a combination of issues. It may be also beneficial to check your plugs for fouling, smell for excess gasoline...
Thanks, Ill check on these. Hopefully I can get it figured out. Its the last one of the last things left to finish the car.
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