[suburban99]

Intermittent stall no rime or reason, at all speeds from idle to 70mph. Will restart sometimes right away, sometimes have to waite up to an hour. Diagnosed as lose of fuel pressure.
Replaced fuel pump with new delco,checked all wiring, cleaned grounds. Replaced fuel pump relay with new delco, checked all wiring that was accessable, for breaks, corosion , arcing. Disconnected all visable conectors and checked for breaks, corosion, arcing.
HELP!!! This vehicle is my bread and butter I'm getting hungry.

 

[84fiero123]

RE: intermittent stall all speeds and idle

did you replace the fuel filter?

Sometimes it's the simplest things.

 

[suburban99]

Re: RE: intermittent stall all speeds and idle

did you replace the fuel filter?

Sometimes it's the simplest things.

Yes. Also replaced the fuel pump sock

 

[84fiero123]

RE: Re: RE: intermittent stall all speeds and idle

Do any codes come up?

You never said, what year, what engine, what fuel system, who did the first diagnosis?

All those things make a difference.

Does it die anytime?

Or just after it's been running for a while?

If it's only after it's been running for a while it may be a computer problem, or electrical.

When a coil goes it can do this. I've had that problem with older trucks, and even cars.

Next time it dies check the fuel pressure right then if it won't start right away. It's simple if its fuel injection and not throttle body injection. Just push the test nipple on the fuel rail if you don't have a tester. You should get a lot of spray if the pump is primed.

If you have a tester just screw it on the nipple.

Like I said before we need to know more about the truck.

 

[unplugged]

Maybe fuel return?

Most fuel injection systems are closed loop. Meaning that fuel is pumped to the injector rail (when used) or the TBI, and unused fuel is sent back via the return line. Like others have said, you didn't mention the year.

I had a similar problem that was hard to diagnose. I went to all the trouble to plumb a fuel pressure gauge and mount in outside the vehicle where I could see it through the windshield. Sure enough, when it started crapping out the pressure dropped to 0-4lbs which wasn't enough for the injection system.

Check the fuel return lines. You should be able to blow air back through and hear air in the fuel tank.

Might just be a bad O2 sensor.

Check out this article on closed loop fuel systems. A little on the technical side, but worth the read. Tech to Tech

 

[suburban99]

RE: Maybe fuel return?

Hi Thanks for the come back. This is a 1999 chevy suburban. The original diagnosis is from the chevy dealership in town. The test was done with a fuel pressure gage attached while driving the vehicle. It stalls hot or cold on the highway or in stop and go traffic. The truck is running a 350 vortec. No codes on the computer.

 

[84fiero123]

RE: Maybe fuel return?

Well that knocks me out, not familiar with the system, sorry.

I really can't understand why it wouldn't kick codes, but who knows.

Just read my signature.

I would say that the new pump is bad, not unheard of.