Will Not Start
August 13th, 2009, 7:59 PM
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Will Not Start
My 1996 5.7L Tahoe will not start. It turns over nicely but does nothing more. I have verified that it has spark and have checked the fuel pressure which is within tolerance. I have replaced the air cleaner, plugs, ingition control module and fuel filter. I have sprayed starter fluid directly in the throat of the carb with no effect. No burbs, chugs, nothing. Outside of timing what could it be? There is no safety lockout that I can see and this year does not have the flashing security light. I'm about out of options here... Any ideas?
August 14th, 2009, 5:47 AM
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It just wouldn't start one morning. That's the point that I tested fuel pressure and changed the fuel and air filters. It then started and I drove it around all day, starting several times. Ran fine. Next morning it would not start again. I again checked the fuel pressure, checked for spark, then replaced the plugs and it still would not start. Then replaced the Ingition Conrol Module. I also shot some starter fluid down the throat just to see if it might fire. Nothing.
I have been checking for spark with an inductive timing light as the plugs are new. I could pull one. What color should the spark be?
I have been checking for spark with an inductive timing light as the plugs are new. I could pull one. What color should the spark be?
Last edited by sawmkw; August 14th, 2009 at 5:53 AM. Reason: Added info
August 14th, 2009, 7:49 AM
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It is yellow. New Bosch platinum HR8DPX gapped at .060. The cap and rotor were replace about 20K miles ago and plug wires have been replaced sometime back. I went ahead and replaced the coil. Still no start.
Last edited by sawmkw; August 14th, 2009 at 4:08 PM. Reason: Additional info
August 14th, 2009, 8:21 PM
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Try to hold the gas pedal to the floor while attempting to start it. Get a can of carburetor cleaner, put the straw on the can and slip it in the throttle body and put the air tube back on. Spray the carb cleaner constantly while someone is trying to start it. What was the fuel pressure when you checked it? It take 3 things to run a engine fuel,spark and compression. Compression does not go away on all cylinders at one time while the truck is sitting overnight. If the spark is nice and blue now then it has to be fuel related.
August 15th, 2009, 5:52 AM
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August 15th, 2009, 7:32 AM
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A couple of days ago my wife was able to get it started by keeping the accelerator to the floor and cranking it for a LONG time. She said it seems to run okay but only drove it down the block and back. The fuel pressure is 60-61 and holds okay for the 5 minutes after pressurizing.
The emission sticker specifies .060 on the gap.
The emission sticker specifies .060 on the gap.
August 15th, 2009, 10:09 AM
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Ther was a TSB that came out changing the gap to .035. But it should still run OK at .060 since that is what it was from the factory.
August 19th, 2009, 9:52 AM
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Hay I just had this problem last weekend at the Outer banks. I changed all that stuff you have change and more. There is a camchaft sensor( under the rotor) and a crankshaft position sensor (behind the harmonic ballancer 6 oclock position). They control the ECM to tell it when to fire the primary side of the coil. but if you have allready changed that out check the wireing going from the sensor to the ECM, a multimeter to do pin to pin checks would not hurt and save some $$ if you do have a wire problem. If it all checks out then flip a coin and change one of the sensors $$. Pick and pull would be a cheaper option. My problem was the crank sensor. I think it was $70 and it was the last thing I changed, very easy to do just need an 8mm socket. As soon as I changed it fired up like a brand new rig and has ran like a champ ever sence then.