96 tahoe fuel pump problem?

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  #1  
Old 09-30-03, 05:35 PM
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96 tahoe fuel pump problem?

1996 tahoe, 2wd, 5.7 with fuel injection. Feb this year fuel pump would not start. Beat the tank with a rubber mallet, got it going, took to the shop. They changed fuel pump. Ran Ok till July, same thing happened, rubber mallet, went to shop. They changed fuel pump. (warranty) Happened again in late August, rubber mallet did not work, towed to shop, shop was not happy, but changed it out anyway, bench tested the fuel pump, it was locked up. And now once again, Sept 30, can't get the fuel pump work. Shop is reputable. This will be the fourth one. I am thinking it has got to be something causing this.

Fuel pump relay seems to be working, I can bench test the relay and am getting continuity when the relay makes. I can jumper around the relay and nothing. Fuses are ok. I am out of Ideas and I am sure the shop techs are going to scratch their heads. Voltmeter on dash with engine running is, and always has been a little less than 14 voltsNo performance problem when fuel pump works, fuel filter was changed at 80k, truck has 116k present.

Any ideas????
 
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  #2  
Old 09-30-03, 05:46 PM
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you may have alot of trash in the tank has the gas tank ever been cleaned out thouroghly at anytime when replacing previous pumps?
it is due for another filter really should be done about every 20000 miles and have seen them plug up within 10000 miles especially if there is alot of sediment in the tank.
 
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Old 09-30-03, 06:03 PM
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Thanks Bejay, I do not know if this was done at any of the change outs, I suspect not. I have always had about the same amount of gas that I took in. Would I see a performance drop in the engine if the screen and/or pump is picking up trash? Could the trash on the filter back flow through the pump? I will change filter and inquire with the shop.
Thanks
DJ
 
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Old 09-30-03, 06:09 PM
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Inline filters need to be changed at regular intervals. However they do not directly affect the fuel pump. They are after the fuel pump and before the induction system. The filter (screen) in the tank is not a serviceable filter. It is usually changed anytime the pump is changed. When they have changed the pump are they changing the entire pump module or just the pump itself? It sounds like you may have a current draw or the pump is not constantly submersed in fuel as it requires this to stay lubricated and cool.
hope this helps ya,
Billy
 
  #5  
Old 09-30-03, 06:11 PM
darrell McCoy
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What brand pump is being used?
Sort of hard to beat OEM. on these.
 
  #6  
Old 09-30-03, 06:23 PM
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darrell and Billy

Thanks

I will check to see if they have been changing the whole thing. As far as brand it is supposed to be a delco.
 
  #7  
Old 09-30-03, 11:00 PM
mike from nj
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you can replace the pump only, and use the old pre-filter, called a 'sock' , or you can replace the pump module, as stated already, and get a free sock with it.

the inline filter (after the pump) should always be replaced regardless if it's one day old when replacing the pump, they can clog from normal use or from the metal from a failing pump, this clogged inline filter will quickly ruin a new pump.

have them drain the tank, take a big rag and wipe the interior of the tank out, new sock, new filter and fresh gas. then take a voltmeter, put it on the amps scale and put it in place of (take out the relay)the fuel pump relay, this will actuate the system, you should have roughly 2-4 amps, higher than 9-10 is too much draw and the pump is working way too hard. also check the connectors on the actual pump itself, they might be spread out a little by now after all the abuse, a new module comes with free connectors and wiring too.

let us know what this reputable shop finds
 
  #8  
Old 10-01-03, 04:09 AM
Joe_F
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All posters gave great information.

Original poster: Verify that Delco parts are being used and CURRENT part #s as GM may have superseded parts due to a problem. Check alldata.com for any known bulletins on this problem, I think something is being overlooked here.
 
  #9  
Old 10-01-03, 06:38 AM
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i would be taking a close look at the connector that plugs into the fuel pump module. chances are the terminals do not provide enuff tension to make a good connection. then when the pump gets replaced, the terminals get 'jiggled' enuff to make contact for awhile, then eventually will lose contact.
 
  #10  
Old 10-01-03, 09:29 AM
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Thanks everyone, you have given me a great list to work on.

DJ
 
  #11  
Old 10-02-03, 04:53 AM
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Turns out to be the connector on the chasis wiring. The female portion had become loose and somehow got pushed back into the bundle were it was not making good connection. Droped the tank down a little, corrected the problem. The mechanic was appologitic, fixed it and I hope to never see him again. (at least not for this problem)

Thanks all
 
  #12  
Old 10-02-03, 05:19 AM
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Thumbs up

cool...
 
  #13  
Old 10-02-03, 06:15 AM
Joe_F
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Thumbs up

Score one for Big Guy. Nice work! Bravo!!!
 
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