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Having Carb and RPM problems

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Old Jul 1, 2010 | 01:50 AM
  #1  
camaro24's Avatar
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From: Westbury Long Island
Car: 1985 Chevrolet Camaro
Engine: V-6/V-8
Transmission: Automatic
Axle/Gears: Regular Axle and Gears
Having Carb and RPM problems

I have a 1985 Camaro 305 hp engine, All Stock and im lost on how my car stalls out when i put my foot on the gas while in drive. It will jump then when it gets to like around 2nd into 3rd gear the car shuts off. BUT when i let the power build up by pressing on the gas lightly while in drive the car will go. I just replaced a bad fuel pump. it did the same before replacing the old fuel pump and hoses. Im thinking its my fuel pressure regulator, or something with the carb. Inside the pan that holds the air filter and covers the carb there is a white slot on the left that has nothing in it, but its attached to a vacuum hose. i would think something like a filter would go inside of it. HELLLPPPP!!
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Old Jul 1, 2010 | 02:39 PM
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five7kid's Avatar
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Originally Posted by camaro24
I have a 1985 Camaro 305 hp engine, All Stock ...
I assume you mean "305 HO engine".

If that is the case, meaning the 8th character of your VIN is "G", you have both an engine-mounted mechanical fuel pump and an in-tank electric fuel pump. The electric pump is prone to failure, and when it does, the mechanical can't keep up (even though it could if the electric wasn't in the tank).

If in fact your VIN 8th character is an "H", that's the base V8, not the "HO", and normally didn't have the in-tank electric pump (although it could have been added as a dealer-installed "vapor lock" kit). Assuming there is no in-tank electric pump, the pick-up in the tank has a filter sock over the pipe that has been known to clog up.

I'm not sure what you're talking about on your air cleaner. Any chance you could post a picture of it?
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Old Jul 1, 2010 | 03:21 PM
  #3  
camaro24's Avatar
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From: Westbury Long Island
Car: 1985 Chevrolet Camaro
Engine: V-6/V-8
Transmission: Automatic
Axle/Gears: Regular Axle and Gears
Re: Having Carb and RPM problems

the 8th character in the VIN is a H and here's the pic of what it looks like inside the pan that white holder to the left that the vacuum hose is attached to. is something supposed to go inside of it? Name:  carb2.jpg
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Size:  4.1 KB Name:  Carb1.jpg
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Size:  4.4 KB
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Old Jul 1, 2010 | 04:55 PM
  #4  
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From: Cary, North Carolina
Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
Re: Having Carb and RPM problems

Supposed to be a small filter in there - that's where the PCV valve connects, the filter simply keeps any oil from getting into the carb in case there's oil blowby past your piston rings and gets sucked up through the PCV valve.
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Old Jul 1, 2010 | 10:35 PM
  #5  
camaro24's Avatar
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From: Westbury Long Island
Car: 1985 Chevrolet Camaro
Engine: V-6/V-8
Transmission: Automatic
Axle/Gears: Regular Axle and Gears
Re: Having Carb and RPM problems

thanks. @camaronewbie. BUT would my problem affect the car starting also? because i live in new york and its been hot lately and everytime i try to start the car cold it wont turn over. I would have to spray ethanol in the carb and let the car warm for bout 30 mins before driving. Is that signs of my carb going bad or the carb needs to be tuned ?
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Old Jul 2, 2010 | 10:06 AM
  #6  
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From: Cary, North Carolina
Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
Re: Having Carb and RPM problems

Oh - sorry - missing that little filter has nothing to do with your problems, I was just answering that portion of the questions for you.
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Old Jul 2, 2010 | 01:18 PM
  #7  
five7kid's Avatar
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Originally Posted by camaronewbie
Supposed to be a small filter in there - that's where the PCV valve connects, the filter simply keeps any oil from getting into the carb in case there's oil blowby past your piston rings and gets sucked up through the PCV valve.
Yes there is supposed to be a filter in there. But, it is not "connected" to the PCV valve, that's in the opposite valve cover, and it's not there to keep oil from getting into the carb.

The PCV valve pulls vapors from the crankcase using engine vacuum (pulling the vapors into the intake tract, where they will be mixed with the air/fuel to be burned in the combustion cycle). In order for it to do that, there has to be an air source into the crankcase. That's what that filter does. It allows filtered air into the valve cover opposite from the one with the PCV valve in it so the crankcase vapors can be efficiently extracted.

Although there should be a filter there to protect your crankcase from ingesting dirt, it doesn't have anything to do with your described symptoms.
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Old Jul 2, 2010 | 01:21 PM
  #8  
five7kid's Avatar
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Originally Posted by camaro24
the 8th character in the VIN is a H ...
Then you have the base V8 LG4 305 cubic inch engine.

Most likely you don't have the in-tank electric pump then, but it is still possible.

How much pedal do you have to give it for it to do this? Flooring it? Or, half throttle? Does it do it if you ease into half throttle? Ease into full throttle?
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Old Jul 3, 2010 | 02:08 AM
  #9  
camaro24's Avatar
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From: Westbury Long Island
Car: 1985 Chevrolet Camaro
Engine: V-6/V-8
Transmission: Automatic
Axle/Gears: Regular Axle and Gears
Re: Having Carb and RPM problems

it does it when i ease into full throttle. Also into half throttle it will move but i would have to ease really slow for the car to move. it will catch speed after about 20 cars go around me, sputter then stall out at around 25-30 mph
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