1994 Chevy Silverado is this a comoputer problem? Random en

HUNTDUCKS

MEMBER
1994 CHEVROLET SILVERADO
V8
4WD
AUTOMATIC
130,000 MILES

This is a 1994 chevy silverado 5.7L V-8. The problem is that the truck will start some times and other times it will not start. Some times it just quits working when you come to a stop or it will keep running util you press the gas. But keep in mind that some times it runs perfect. When it wont start you have to pump the accelerator really hard, this is a TBI (thrittle body injection) you should not need to pump a TBI, when you turn over the engin and it will turn over but not start it has spark. When you finaly get it started black smoke comes out of the exhaust will fuel in it. It runs really crapy too. We have replaced the fuel filter, fuel pump, fuel strainer, ignition coil, ignition control module, distributer cap, rotor, codes. Some times if you can get it started it will get the check engin light but will eventualy even out and run perfect and the light will cut off and give no codes. The car shop gave up on it so this is my last hope. They have replaced sencors and tried two diff tbis. I think that it is the ecm. What do you think?

5 Replies

MASTERTECHTIM

MECHANIC
4,749 POSTS

Sounds like you have a leaking fuel injector. Remove air cleaner assembly and watch both injectors. See is one drips fuel while the other sprays nice. Also check to see if a injector drips fuel after you turn it off. If any fuel comes out, even a couple drips, then you have a problem with that injector.

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Monday, January 7th, 2008 AT 1:26 PM

HUNTDUCKS

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4 POSTS

Did you even read what I posted? I said that they had put two more tbis on the truck and it did the same thing. Next time you should read

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Monday, January 7th, 2008 AT 1:33 PM

MASTERTECHTIM

MECHANIC
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Just trying to help dude. You have already pitched a bunch of parts at it that didnt fix it. Now if you checked for fuel leaking out of the injectors when the truck is shut off, than you have eliminated injector wiring and ecm. I assume you have checked that your egr valve is not stuck open. I also assume youve checked engine timing.

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Monday, January 7th, 2008 AT 2:02 PM

HUNTDUCKS

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4 POSTS

The problem is intermentent so I would have to be an electrical problem, right?If it was timing it would run like crap all the time. No fuel leakin egr valve is not suck open b/c then it would not be an intermentent problem. So that would mean there is a good chanch that it is the ecm right?

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Monday, January 7th, 2008 AT 2:54 PM

MASTERTECHTIM

MECHANIC
4,749 POSTS

Ive worked for chevrolet for 15 yrs and I have seen every imaginable problem with this vehicle. Although you could have a bad ecm in my opinion is unlikely. I have replaced the distributor mainshaft in probably a hundred of these trucks. What happens is the reluctor wheel on the shaft cracks and when the car heats and cools the reluctor will rotate on the shaft causing retarded or advanced timing. A easy way to check this is by checking the timing. It should be the same every time you check it with the est line disconnected. (The est connector to check the timing is under the passenger side of dash. It is taped along side the harness.) And if its intermittant I would unplug the egr valve just to make sure. Also the ecm ground wire at the thermostat housing stud. Lightly pull on it to make sure the wire is not broken inside the insulation.