Fuel Pump Problems Again

[harbison]

1998 Tahoe 2 Dr 4WD 189K

Having problems with fuel pump again. Has been replaced multiple times. Fuel filter replaced as well. Fuel Pump relay replaced. Was getting hard to start so we replaced battery with more cold cranking amps and it helped. Started on first try. Now after a couple of months, hard time starting again. I hooked up battery charger and it started just fine. I can replace pump again (lifetime warranty) but that really doesn't solve the problem. Any ideas?

 

[Matahoe]

What's the pressure doing at KOEO? How is it at idle? Quick snap?

 

[harbison]

KOEO pressure - 50, At idle - 50. When I hook up the battery charger (which takes the battery to 13.85), KOEO is 58.

 

[Matahoe]

Hard to start all the time? Cranks slow?

 

[PG01]

I honestly believe you’ve got a ground issues

 

[harbison]

Hard to start all the time? Cranks slow?

Doesn't crank slow at all. Hardest to start after it's been sitting a while.

 

[Matahoe]

Yeah, seems like your pump is ok. If the engine is hard to start with good fuel pressure then you've got some type of base timing, or sensor out of whack. If you had a ground issue at the pump you wouldn't be getting 50 psi.

 

[Matahoe]

Doesn't crank slow at all. Hardest to start after it's been sitting a while.

...this is also a classic symptom of a leaking fuel pressure regulator

 

[east302]

Doesn't crank slow at all. Hardest to start after it's been sitting a while.

GM’s fuel pressure spec is 60-66 psi, so you’re on the low end. What does the pressure do when you turn off the ignition? It should hold fairly close for a while.

If you have a scanner, check the readout of the coolant temperature sensor. It should be reporting something close to ambient when cold and near the thermostat setpoint when warm. If it’s reporting some bizarre number that can cause the computer to botch fuel delivery and make for hard starts, particularly when warm or within a few minutes of it last running. A workaround is holding the pedal to the floor while cranking, this temporarily stops injector pulses (a.k.a. clear flood mode).


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[liquify33]

I had a similar issue in a different car from an aftermarket car alarm.
The starter interrupt the car stereo shop used was 16gauge wire with no heat shielding.
That wire eventually burned up and would only start when the engine was cold. Every summer the car ate a starter or battery.

You may have something similar based on symptoms IMO.