Fuel and Ignition Fuel Pumps and Systems, Ignition and Spark Systems

Engine sputtering ... please help!

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Old 11-14-2006, 12:26 PM
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Engine sputtering ... please help!

Ok I have the 5.7 in my 94 and I noticed that the recirc fuel line was cut. Being that the engine was sputtering and it was acting like it wasn't getting enough fuel I figured that was it so I replaced it but it didn't change a thing. My engine starts sputtering constantly say 5 minutes after I start the car, a couple occasions the car has actually turned off. The car does a little better right after I fill up the gas tank but this last time I filled it up I only got about 50 miles before the tank was completely empty. I have another 94 camaro I can transfer parts from I just have no idea what needs to be replaced. Fuel injectors or fuel filter maybe? Help would be greatly appreciated. Thanks
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Old 11-15-2006, 12:00 PM
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Have you checked the fuel pressure, under load, when its "sputtering"?

Did you check the supply line to make sure that one wasn't cut as well? Hard to figure where 12-14 gallons of fuel could go in 50 miles. It would have to be running pure fuel to use up that much that fast. But a pressure check will point you in the right direction.
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Old 11-15-2006, 05:03 PM
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I'm not too knowledgeable about cars just yet ... explain to me how I can check the fuel pressure if you have the time? Also I haven't noticed any gas leaks ... the only leaks I know of is a small oil leak from a stripped gasket and an exhaust leak

Last edited by vincentiarr; 11-15-2006 at 05:05 PM.
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Old 11-15-2006, 05:50 PM
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You need a fuel pressure test gauge... mechanical gauge on an ~18" hose. The hose will have a -4AN connection on it, that screws directly onto the "Schrader valve" on the fuel line behind the intake manifold. You unscrew the plastic cap first.... see Shoebox's photo:

http://shbox.com/1/fp_reg.jpg

When you get the pressure gauge attached, start the engine, and remove the vacuum control hose from the fuel pressure regulator. Hold your finger over the end of the line, or plug it so there's no vacuum leak. The fuel pressure should read 43.5psi at idle, and GM accepts anything from 41-47psi.

Reconnect the vacuum line, and the fuel pressure should drop about 8psi from the "no vacuum" reading, with a stock cam.

Then tape the gauge to the outside of the windshield, take the car out on the road, to WOT/max load/near max RPM. The fuel pressure should never go below 41psi.
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Old 11-15-2006, 11:14 PM
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50 miles on a tank of gas? Could it maybe an injector getting stuck open therefore just dumping fuel? How many miles on the car?

Ken R.
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Old 11-17-2006, 04:36 PM
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140000 on the body about 5000 or less on the engine but I'm not sure if everything under the hood was replaced or just somethings so maybe the injectors and stuff have 140k on them
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Old 11-25-2006, 11:22 PM
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Sounds to me like your fuel injectors are sticking and just dumping way too much fuel into your motor. And that gas is just sitting on your plugs, and sound like it is making your plugs foul up. When you get out of the car does it have a pure gasoline smell out of it especially from the exhaust?

-Dax
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Old 12-06-2006, 07:21 PM
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Is your check engine light on?
Do you have black smoke exiting the exhaust?
Have you change the fuel filter in the last 15,000 miles?
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Old 12-07-2006, 09:45 AM
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Originally Posted by roguedriver
50 miles on a tank of gas?


That thing is going to blow up!! All the raw gas must be pouring out the exhaust? How you looked there??
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Old 12-07-2006, 08:47 PM
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i would lean toward a leak somewhere. stuck open injectors that bad would hydrolock the motor and not crank. the black smoke is horrible and the check engine light will flash stating a catalytic converter damaging misfire is happening. look very carefully for a leak idling, after fill up, short around the block cruise
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