1997 Chevy Truck V8 fuel pump failure

chevrolet
1500

#1

Several years ago I had to replace the fuel pump - truck had about 100,000 miles. Within the last 4 - 5 months I have replaced the fuel pump twice and just today (about two months since the last replacement), the fuel pump has failed again. That has been the pattern now for the last several months. I have had the work done by one of the reputable car repair shops in town - they have also done work on my 2004 Impala with no issues with the repair. There must be something else going on besides just the fuel pump going bad. What would cause so many fuel pump failures.


#2

You don’t allow the fuel tank to run down to almost empty, do you?

Tester


#3

I had repeated failures with GM fuel pumps also, to the point where if I had them start again I would trade cars. But you have to replace the wire harness too and also the relay at the same time. Wires also get old and I replaced the wiring all the way from the pump to the computer. Keeping a half tank of gas all the time also helps longevity. If there was a super duty after-market pump available I would have sure used that instead. Cost me about $1000 every time.


#4

Just a couple of questions for @wcsmith: Have you been replacing the canister fuel filter (not referring to the sock on the pump itself)? A partially clogged filter can cause tremendous back pressure at the fuel pump which can cause early pump failure.

Have you been using original equipment pumps (AC Delco)? It’s not a part you want to economize on considering the difficulty replacing it.

A word on GM fuel pump failures: My last 8 cars have been GM pump in tank cars and only one has had one fail and that was at 267,000 miles. I guess every ones experience is different.


#5

GM trucks of that era are notorious for failed pumps. The best you can get is an original Delco pump exactly like the one that failed.

But 100K is not bad. They usually go at 75K. The cheap Chinese replacements die MUCH earlier.


#6

The most likely problem is that the tank is not being cleaned out when the pump is replaced. Have seen this countless times with repeated pump failure. Fine sand is a killer of fuel pumps and you’d be amazed at how much sand you buy every time you gas up.


#7

Shouldn’t the fuel filter stop the sand from getting thru? The fuel filter is being replace along with the fuel pump.

Warren


#8

Which fuel filter is being replaced? The one that attaches to the fuel pump or the external inline filter or both?

Also, the external filter is a much finer so any sand which is getting through the internal filter (sock) could clog the external filter.


#9

Never thought of sand but my tank had been replaced. At any rate, the sock filter in the tank is not likely to be able to filter out fine grains of sand but the in line filter needs to be replaced just for warranty purposes. Can’t imagine any shop replacing the pump and not the in-line filter. I never had problems with the original pumps on GM cars, but just the replacements. I always got well over 100, 200, 300K with the original pumps but once replaced became a problem.


#10

The pickup screen does not filter that fine of particulates and the filter is after the pump. SOP here at my shop is to wash out and dry tank when replacing pump. Helps keep the comebacks down.


#11

Has the possibility that the pumps are not actually bad been considered? Maybe it’s an intermittent pump control issue, pigtail wiring fault, or whatever.

There should be a pump test plug on that truck somewhere. Next time the pump “fails” you might consider running a jumper wire from the hot side of the battery to that test plug. If the pump is good it will run when this is done and will tell you the problem is in the pump controls.
The jumper should not be left in place as it is only a test method.


#12

My guesses, in order of likelihood

  • Fuel pump operating voltage too low due to higher than normal resistance somewhere in the circuit. This can cause an over-current condition w/the resultant heat and early failure. Verify the voltage at the pump input is correct.

  • Restricted flow somewhere between pump input and injection rail. Replace in-line fuel filter(s), check that pump inlet filter isn’t clogged, and check rail fuel pressure.

  • Faulty pumps being installed. Spring for an oem unit from the dealer next time.


#13

We get genuine AC Delco pumps, and they last so many years before falling

We’ve verified and ruled out everything else countless times

They’re just junky parts

I agree with Mustangman . . . but I can only click on the “heart” symbol


#14

I always used Delco pumps but the guys had two in a row right out of the box that were bad. Like I said the ones installed at the factory seem to last quite a while but the replacements don’t at least in my limited experience.


#15

just for giggles, are the pumps actually being tested for bad? if so, what is the pump removal procedure? Drop the tank, or lift off the bed?

Trying the opposite pump removal method may open up some different views in wiring that may be causing an issue.


#16

Well these are all great suggestions and I will have the repair shop take them in consideration, however as of now, school is still out as to what is causing multiple pump failures. Once it gets settled, I’ll post the results.

Thanks everyone…


#17

I’m going to stick with my theory that these pumps not failing and that the issue is a control or pigtail wiring issue.