[HITDOGG]

Hello folks. I ran into a little problem on Wednesday. 01 Tahoe with the 5.3. Wouldn’t hardly run on my way to work that morning. It would start cutting out when I got on the throttle. Ran fine on the way home from work. Once I got home, turned it off, it wouldn’t crank back. Felt like a fuel problem to me. I was getting a little low on gas, but the light hadn’t come on yet and the gauge was reading probably 1/8 of a tank. So I put probably 1/4 of a gallon in it that I had left over from grass cutting season. Still wouldn’t crank, and the fuel pump seemed to be a little louder than normal. I could hear it running. Sprayed some crab cleaner in the breather tube and finally got it to crank. Took yesterday off from looking at it. Went out this morning, it fired right up.
Decided to see what the fuel pressure was running. About 40 psi but only when the fuel pump is running or the engine is running. The fuel pressure regulator has an adjustment screw, so I cranked the pressure up to about 62, which I read the psi is supposed to be 55 to 62. And it does seem to be cranking just fine now. Now to my question. Should that pressure remain constant? When the engine shuts off, or if the fuel pump ain’t running, I show no pressure on the fuel rail. Is that correct? I do plan on changing the fuel filter. I was just wondering if there was a check valve messing up somewhere, or if it is leaking back through the pump. Thanks in advance

 

[MrShorty]

I am not intimately familiar with your specific system, but every other high pressure fuel system that I am aware of has some kind of check valve to prevent all the fuel in the line from draining back into the tank so it is easier to start. How quickly does the pressure come back up if you turn the key on but not to start?

A problem with the check valve usually doesn't impact how well it runs, because once the pressure is up where it should be, it should run fine.

 

[Cowboytrukr]

Low pressure to the tune of 40psi should not be compensated for by cranking the regulator up. The pump is failing.

 

[PlaywithTBI]

The pump is failing.

^^^This or, maybe one of the injectors is leaking?

 

[HITDOGG]

Thanks for the replies guys. I went ahead and dropped the tank and pulled the fuel pump. New one should be at the house today. I'll back off on the regulator if I need to. I was told the check valve is internal to the pump. Is this true?

 

[OpalLacod]

I was told the check valve is internal to the pump. Is this true?

If you buy the one with the check valve, yes. My model year has it listed as optional, in some cases.

 

[HITDOGG]

I replaced the pump with the exact part number that was on the old one. Pressure was holding after priming the line. So it must be the pump with the internal check. It seems to be much quieter.

 

[Cowboytrukr]

What’s the word, Dogg. Did that fix the problem?

 

[HITDOGG]

What’s the word, Dogg. Did that fix the problem?

It seems to have, quicker start this morning. Ran great to work.

 

[Cowboytrukr]

Nice!!!

 

[Aquamania001]

 

[PlaywithTBI]

I love it when a plan comes together! 🍻