Fuel Problem, 2001 Sierra

[Coalbunny]

My truck is a 2001 GMC Sierra Z71 4x4, 5.3 liter V8.

The problem began without me noticing it. Periodically my truck would bog down a little bit, and since we still have snow and ice patches here, I’d goose the accelerator thinking it was the snow and ice. I became suspicious after the bogging happened on dry pavement a few times.

 

The day I noted it was bogging down on dry pavement, and about 20-30 minutes later my truck died. Well, now it acts as if it’s starved for fuel.

 

What I have done so far is....

... I removed the Vortec Cover and released the fuel pressure;

... I crawled underneath and removed the fuel filter;

... Not having the resources to buy another filter, I “manually” blew the filter clear. At first it was tough, and then “plah”, a big wad if yuck came out of the filter. I was happy. I found the problem. Or so I thought.

 

I put the filter back, tightened everything down, and tried to start the truck.

This time, while it would not “really” start, it started more than before the filter removal. I have two brief videos of the attempted start.

 

When it wouldn’t start, I had a friend start it while I released fuel pressure, thinking maybe it’s because of air bubbles in the line. Gas came out, not spraying, but pouring. I felt there was no need to check the fuses and relays since the pump was delivering fuel.

 

 

Ok. First thing that comes to mind is there is gas making it through the filter, but maybe not enough for the engine? Gas is making it to the fuel rail. I do not have a fuel pressure gauge available, so any suggestions on other-than-normal methods to tell the approximate pressure are welcome. At this time I am planning on getting a filter specifically for my truck in the morning, so I won’t have to improvise anything for the filter.

 

 

This is not something I can work on anytime I want because of where it’s parked. I have to bum a ride from a friend as it’s sitting in a public parking sight an hour away....

 

Suggestions and insight are more than welcome.

[Jsdirt]

Borrow cash & get yourself a new fuel filter! No way around it - if it was that plugged, blowing it out isn't going to do much ..... although it should at least idle. If it won't even idle you may need a new pump ... but change that filter first!

[Coalbunny]

That is my plan. I will also see if there is someone I can borrow a fuel pressure gauge.

[Coalbunny]

Ok, I bought the correct fuel filter.

Took the safety precautions, and removed the relay for the fuel pump.

Depressurized the fuel system.

Removed the old pump and installed the new.

Put the relay back in.

*Tried* to pressurize the fuel system.

All *should* be good.

 

But it's not. Not only will it not deliver any fuel to the fuel rail, I hear no noise from the fuel pump now.

 

Can removing the relay damage the relay? Can I put the relay in wrong?

I have no idea.

Help!

What did I do wrong?

[doubled1]

Check for short in wiring to fuel pump in engine compartment

[gmtech]

Before you go hunting a "short" check for voltage at the pump on the gray wire.

 

Im confused, did you replace the pump or just the filter?

[Coalbunny]

Just the filter.

 

There should not be a problem with the fuel pump.

 

I am thinking this pump problem arose after I pulled the relay. So I'm thinking maybe I did something wrong taking the relay out or putting it back in....?

 

 

ETA: I got my truck back home and will start working with it. I tried starting it before I got it pulled here, and it gave a couple of bites.

[Coalbunny]

I finally got a hold of a fuel pressure gauge and it tested around 27 pounds. Not enough. So now I'm waiting to get some help to drop the tank. I back is messed up from a wreck a few years ago, so unless I have someone to help me with this, I won't drop the tank. I certainly plan on cutting a hole in the bed though, for future fuel pump replacement.

 

Any advice on dropping the tank is welcome. I did consider tilting the bed, but with an auxiliary fuel tank and tool box and ladder rack, likely to be easier to drop the tank. Not to mention the winter season junk that's sitting in back right now!

[Coalbunny]

Ok, I have it replaced. Not sure how long it'll last, but it's in and my truck is running.

 

And it looks like I owe the dealership an apology. Turns out they had replaced the fuel pump after all. It's an AC Delco pump. But it still failed (35,000 or so miles later). The new replacement is a Delphi unit. I hope it last me a lot longer than 35,000 miles.

[redvett]

Use clean gas and do not go below 1/4 tank and the pump should last at least 100000 mi.

[Coalbunny]

I better get more than 100K out of that pump! Man, they are expensive! And the PIA to install? If I didn't have the auxillary fuel tank I'd cut a hole in the bed to access it!