2004 gmc envoy 4.2L engine will turn over but want start no spark at the spark plugs boots why? what i need to check to fix the problem?

Other answer:

Joe Russell:
The ignition switch has a lot of functions, and one of them is to power the PCM and engine controls WHILE the starter is cranking. That's what might have gone bad for you. You might also have a bad fuse in the PCM chain, and I'd recommend you check them all out under the hood. The rear fuse block doesn't have anything critical in that chain.

Testing the ignition switch requires a meter and a schematic and a bit of experience. I can post parts of the schematic, but I don't know if you have a meter and know how to use it.

Important fuses are 10, 22, 23, 28, 29, and 47 under the hood.

thebax2006:
While someone is cranking the motor over listen for the fuel injectors to be clicking. If no spark and no injector pulse you may have a bad crankshaft sensor or in your case sensors.
DR + Mrs Bears face:
Hi if only it was case of just checking sounds a lot more serious like it needs spare parts. sorry have to be purchased.
Skoda John:
Where is there power to?
You need to trace it back.

Leave a Reply