you shut it off, would not run again for several hours

2004 CHEVROLET IMPALA
175,000 MILES • 3.8L • V6 • 2WD • AUTOMATIC
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CA1970
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Girlfriends car, started out it would crank in morning and run fine, but when you shut it off, would not run again for several hours. Now it wont run at all. I have changed the plugs, plug wires, two coil packs, the ignition control module and the cam sensor all with new parts. have tried resetting the security system, still no go, scanner only showed codes for cam sensor and EVAP purge valve (which I also changed) looking for other ideas to chase down but am currently stumped for ideas. any suggestions? have a sneaky feeling it is something to do with security system, but not sure.
Jan 5, 2019 at 6:15 PM
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HARRY P
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At 175,000 miles, I'd check the fuel pump. In the past, when it would start but not run later on, the pump would warm up and lose pressure output. That output would get down to the point where it was enough to run the car, but not enough to start it. This is a common issue, believe it or not. It could even have completely shut off. Get a friend to turn the key on while you lay on the ground near the fuel tank and listen for a humming sound that lasts about two or three seconds. That sound is the fuel pump priming the system. Obviously if you don't hear it, then the pump isn't running at all. If you do hear it, it may not be putting out enough pressure. You can borrow a fuel pressure test gauge from AutoZone or any other parts shop with a loan-a-tool program. Basically, what you'll do is release the fuel pressure, hook up the gauge, and then turn the key on and see what it reads. Here's our general guide on the process:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator


Check out the diagrams (Below). Let us know what happens and please upload pictures or videos of the problem.
Jan 5, 2019 at 8:38 PM
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CA1970
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I found the problem. When I was working on it, it was 3:00 am, and i was very tired, I forgot to hook the wire harness up to the ICM. Very embarrassed. :/ But thanks for quick response!
Jan 8, 2019 at 4:12 PM
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HARRY P
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Haha that's great to hear! I'm glad that you got it figured out, because it would've been a while before I had you rechecking your work. And don't worry. You're talking to a guy who got towed home one day because the truck stalled and wouldn't start back up. I went out to start working the next morning and it took me all of three seconds to fix it. The coil wire came loose. I snapped it back in and she fired right up.
Jan 8, 2019 at 7:12 PM