Im having problems with my 1997 4x4 chevy blazer LS. It has a 4.3L V6 Vortec Engine. Came home from work ran fine like usual. The next day get in to go to work and it just cranked and cranked but wouldnt turn over. I checked my fuel pressure, the pressure was fine. You can hear the fuel pump engage, and I have pressure so I know its not my pump. Changed my Fuel pump regulator, and now it cranks and trys to start but wont turn over still. When I try to start it, it will backfire, as if its getting to much air and no fuel or maybe it just aint gettin no fire. Im not sure. Any ideas would be greatly appreciated. Thanks.

 

How much fuel pressure do you have?

 

Was searching through the forums and went through a list of a self diagnostics List. Could a "sticky" Thermostat cause the engine not starting by flooding the engine, because its feeding it to much fuel?

Well i didnt check it with a actual gauge. I just did a visual check at the purge valve on the fuel line. It had enough pressure to spray my windshield with fuel, so Im guessing the pressure was pretty good.

 

You'd be surprised. 60-65 psi and mine runs like a champ, 50-55 and it did exactly what you're describing. Fuel at 40 psi will spray all over the place and the vehicle will never start.

 

Oh, well I didnt know it could make that big of a difference. But could a fuel pump work fine one day and then the next just go out? I thought something like that just gets progressively worse over time and just doesnt go out overnight. Right?

 

Yes, it can happen that fast. When mine went out last week, it worked fine to get my wife to Wendy's for lunch, four hours later I was towing it home. While diagnosing the problem, I watched it crap out worse every time I turned the key by monitoring, you guessed it, the fuel pressure gauge! They're pretty cheap, and I think AutoZone will loan them out.

 

no when fuel pumps die its usually sudden, and dead. you can try beating on the fuel tank, sometimes that will get it to start 1 more time, but not if the pressure isnt there.

 

I'm not saying that it is your fuel pump, btw, I'm just saying that you can't rule it out yet.

 

Oh, ok. Well thats a slight relief. What else could be causing the problem though? Could it be bad spark plug wires, and I aint getting no fire?

 

Yep, no spark could cause that, but you said it was trying to start so I'd assume theres spark. You'd need to check to be sure.

Heres a good jump off point.

https://blazerforum.com/forum/engine-transmission-35/engine-cranks-but-does-not-run-45944/