2004 Aveo stalling

2004 Aveo with around 107k miles. Started randomly stalling after warm up on highway. Normally around
55 mpg, would cut out a couple of times and then engine dies. No codes on scanner.

New timing belt, cam sensor, spark plugs and wires, coil pack, fuel pump relay, gas cap and checked for vacuum leaks.

Found a cracked hose and replaced on MAP sensor (still dies though). Runs great while cold and after about 6 miles and it's good and warm, it'll randomly die on the highway. Pull over and turn everything off for about 2 minutes and it starts up and runs great again. If trying to start without turning off first, it'll just crank. Has to be turned off to reset whatever it is that's happening.

Mechanic thinks it's the fuel pump pressuring up causing the relay to trip.

I see that there's numerous comments about the same issue but, no one came back and stated what the problem was on their car.

Thanks for any help. I'm getting sick of putting money into this work car.

Quote:

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Originally Posted by BTyler

... If trying to start without turning off first, it'll just crank. Has to be turned off to reset whatever it is that's happening....

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If the required wait is consistent as you describe, that's actually a fortunate thing because it will allow you to at least partially diagnose the problem.

Next time it stalls, immediately connect a spark tester to one of the plugs. In order to do this quickly, you'll need to leave the engine cover removed. You can crank the engine while standing outside, and look through the gap in the bottom of the hood, in order to see if the tester is flashing.

The other test you can do after it stalls is disconnect the intake hose and spray in a small amount of carb cleaner and then crank it over to see if it will try to start on the fluid.

After doing those tests you will be on the way to diagnosing the problem. Fuel would be simpler than spark, but you can also run additional tests with a multimeter if the problem turns out to be spark. My WAG is an electrical/ignition issue, but diagnosis is the only way to go with something like this.

Quote:

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Originally Posted by avguy

If the required wait is consistent as you describe, that's actually a fortunate thing because it will allow you to at least partially diagnose the problem.

Next time it stalls, immediately connect a spark tester to one of the plugs. In order to do this quickly, you'll need to leave the engine cover removed. You can crank the engine while standing outside, and look through the gap in the bottom of the hood, in order to see if the tester is flashing.

The other test you can do after it stalls is disconnect the intake hose and spray in a small amount of carb cleaner and then crank it over to see if it will try to start on the fluid.

After doing those tests you will be on the way to diagnosing the problem. Fuel would be simpler than spark, but you can also run additional tests with a multimeter if the problem turns out to be spark. My WAG is an electrical/ignition issue, but diagnosis is the only way to go with something like this.

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Thanks for the information.

Took out the back seat this weekend and started up, could hear the pump at first making a steady noise. Then started to sound like
an electrical short with muffled pops and crackles. Car continued to idle fine and didn't stall.

Plan and taking it for a test drive tonight with the seat out to see if the pump actually dies.

Looked but did not see a port under the hood to plug in a fuel pump gauge.

Put in new fuel pump and took for a drive. Car died just like before. Still can not figure out why. Any ideas?

It might just be the relay? I know you said it is new, was it OEM? I think it will swap with the fan relay?

There should be a valve under a black cap right on top of the fuel rail to test pressure. Problem is, trying to read the gauge in time. Some hold pressure with a release to show top pressure, even after the systems "bleed" down.

Does your car have a fuel filter on the front of the tank? From my understanding IF it does, that has the built in pressure regulator for the system. If you car does not, then it is on the pump.

If you have limited tools. Next time it doesn't start, if you are not sure if it is a fuel issue or not yet. Try spraying starting fluid in it while cranking, if it will try running on starting fluid, then it is lacking fuel. You might have a vapor lock issue kind of like your mechanic said. But if your car is equipped with a filter, it could be clogged.

When you did the fuel pump, what was the condition of the old sock? did you look in the bottom of the tank? was it acceptably clean?

Well after 3 long weeks, a mechanic in town finally (I hope) figured out that the cable to the camshaft sensor was shorting out and did not have a good connection. He could not find the sensor connector without having to purchase a new harness for the entire engine at $700. He cleaned the plugs and it seems to work fine for the past 3 days.

I heard comments about a re-learn which the mechanic stated was required if you change the sensor. Keep this in mind if you do it yourself.