So, I've been here awhile. I know all the common fuel system woes on these trucks. But I can't figure this one out.

My truck (95, Vin W) has developed an appetite for fuel pumps. Like, not even 500 miles, and fuel pressure at the pump is down below 50, when it should be like 80-100 psi. Same at the test port. About 48-50, drops as soon as the pump is off. I isolated the pump, testing at the fuel filter fittings, and the pump is definitely the problem.

There's only a 0.6v drop from battery to pump connecter, so I don't think that's the problem. I change the filter and sock when I do a new pump, also.

Gonna pump it dry and drop the tank today, and investigate.

Also, I only use ac delco or Delphi pumps. I'm about ready to throw the cheapest crap O'Reilly sells in there, and just abuse the lifetime warranty.

 

 

George, there are no solder connections, it plugs in to a harness outside the tank. That's where I measured voltage. Ground checks out, too.

After replacing the pumps, I always check pressure at the fuel filter fitting, just to verify that it's fixed.

I'm thinking it might be trash in the tank. I just cut open the pump strainer, and it's pretty grungy looking. I'll see if I can get a pic up

 

So, here's the strainer, cut open.

I'm thinking I'll clean the tank out as best I can, and see how long the new pump lasts.

The Delphi I bought from advance Auto has a lifetime warranty, and I have my receipt, so I'll be able to get a new one today.

 

Out of curiosity, You may also cut the fuel filter and see what You find inside. Unluckily, in this design, first the pump (in tank), filter second (by the frame)....

 

Good idea. I'm gonna replace the filter anyway.

I'm going to order a new sending unit as well. One of the in tank connections on mine is kinda melted. Although there is still perfect continuity through it.

 

Sounds like your doing things right. I used a Delphi at 100,000 miles and have gotten another 100,000 miles on the new one. That said, I don't know if anything has changed but that pump generally has a good reputation.

George

 

I have heard of people 'blowing out' the fuel lines to clean them out. I don't know how to do that, but it sounds like a good idea. If you don't have a air hose, how about disconnecting the fuel filter and running the fuel pump to push out the bad gas. Use a 2 liter catch bottle of some sort to catch the gas. I am sure you are changing the fuel filter with the new fuel pump.

 

That's what I've always heard, and all I've ever put on this truck is either ac delco, or Delphi. Had the truck six years, put about 100k miles on it, and I'm probably on the sixth pump. This will be the third one this year. New pump in Jan, again in April, and now again in September. There's gotta be something else going on.

 

That's how I've been draining the tank, so I can drop it. Pump it dry from the fuel filter fitting. But then I just put the same gas back in lol.

I have air, and I might try blowing out the line, but unless I take it apart where it goes into the intake, I won't get the front half of the lines


Edit: cut open the fuel filter, it's kinda yucky also. Not sure how dirty they're supposed to look, though.