Bad fuel Pump? (Solved)

[WestCoastie]

See the post below for specific fuel pressure test and specs. Replace the fuel pump relay just to rule it out; maybe test with the old one and again with a new one.

The Flex Fuel system on your year will have an inline fuel filter on the driver's side frame rail (near the alcohol sensor); consider replacing it if the age is unknown.

Fuel delivery?

I’ve heard that the harness is notorious for faulting on these pumps is this true. I can replace the relay but I feel like that’s another thing that’s just spending more money. Mechanically you typical don’t get intermittent issues that’s usually electrical faults is there specific grounds that...

www.tahoeyukonforum.com

New fuel filter with maybe 1k on it.

Relay is brand new and good. Fuse is good.

I forgot to mention that I have an occasional issue with the fuel gauge, where it reads empty when I know it has fuel in it. This issue is very intermittent so I mostly forget about it.

I went ahead and ordered the fuel pump. Now I hope it warms up enough for me to want to do it.

 

[mattbta]

Did you replace the Cam Position Sensor during the rebuild and/or recently?

 

[Fless]

Did you replace the Cam Position Sensor during the rebuild and/or recently?

And/or the crank sensor? Either one would be preferably OE, not aftermarket. And if either one was changed, a correlation procedure is highly recommended.

Also is the hard start on a cold engine, or hot, or both?

You may need a new fuel pump lock ring, too, depending on the condition of the existing one.

 

[WestCoastie]

Did you replace the Cam Position Sensor during the rebuild and/or recently?

Yes, I replaced cam and crank sensors. Mostly because they fell apart getting them off. Scanner shows them working though. That thought definitely ran through my head though.

 

[WestCoastie]

And/or the crank sensor? Either one would be preferably OE, not aftermarket. And if either one was changed, a correlation procedure is highly recommended.

Also is the hard start on a cold engine, or hot, or both?

You may need a new fuel pump lock ring, too, depending on the condition of the existing one.

The hard start happened whenever it felt like it, hot or cold didn’t make a difference. The hard start happened more often than not.

Might need a new lock ring. I’m holding out hope I don’t. It was a Texas plains truck and now in the NW where it gets washed regularly. There is almost no rust on it.

 

[WestCoastie]

Would fuel pressure regulator on the rail be a culprit? I have not changed it out nor do I know how to test it.

 

[RST Dana]

If you apply voltage to the pump and it works, then maybe the issue is voltage source coming to the pump. Any testing done on the voltage source?

 

[mattbta]

Yes, I replaced cam and crank sensors. Mostly because they fell apart getting them off. Scanner shows them working though. That thought definitely ran through my head though.

Did you use OEM? If not, does it do this:

That's mine with a non OEM cam sensor in it. Swapped to OEM and it starts first try, every try. I did a cam/crank correlation as Fless suggests, but these engines just don't like non OEM cam sensors. (I did the relearn again after putting in the OEM).

 

[WestCoastie]

I mean that does sound like it. But I feel like all hard starts kind of sound like that?

I spent the extra money after reading on here and when I did the rebuild I got OEM sensors.

The thing that’s got me leaning toward fuel pump, is its obviously been a problem in the past. The random fuel gauge issue. And the fact that it won’t keep pressure up at the rail after everything is turned off.

 

[WestCoastie]

If you apply voltage to the pump and it works, then maybe the issue is voltage source coming to the pump. Any testing done on the voltage source?

Like the battery or ECU