3 bad fuel pumps in a row, unbelievable!

[SunlitComet]

http://www.sunlitcomet.com/pdf/automotive/tahoe/98-99/1999-Tahoe-Fuel-Sytem-Diagnosis.pdf

 

[Korn]

I just went thru replacing a pump in my 95 4 door, what a pain in the ass. First it only had 5lbs of pressure. I swapped the pump and when I got it all back together it didn't have ANY pressure. After some trouble shooting I found that the pump wiring only had 8 volts. :O Perhaps you are having a voltage issue ...

That is something I should check. If the voltage is low what would cause it to be low, I am guessing it should have 12 volts?

 

[retorq]

Supposed to be 12 or really close. I had a pinched wire at the frame rail.

 

[Korn]

Supposed to be 12 or really close. I had a pinched wire at the frame rail.

If its low, just saying if its low, then why would the Airtex pump work the other wouldnt. Im goint to test it when I get it back home from town.

 

[THE-HOE]

I agree with the above statement about voltage. At one time my 255 pump could not push my tahoe much past 400rwhp because of low fuel pressure, I did some testing and found out that my pump was only getting about 9 volts. Put a racetronix wiring harness directly to the pump from the alternator to give it about 14 volts and it let me get much more fuel pressure, and hp.

I am uncertain about why the airtex pump would work but the others wouldn't, maybe the airtex is just designed a little different, and does not need all the voltage as the other ones??? Im confused about that one

 

[SunlitComet]

either a high resistive short or carbon buildup on the fuel pump relay will cause a voltage drop.

 

[Jaycenk]

If its low, just saying if its low, then why would the Airtex pump work the other wouldnt. Im goint to test it when I get it back home from town.

It could also be that when you replaced it the newer pump would have wanted more amps then the older worn out stock pump due to the fresh motor in it and after running it may have caused some bolt neck draw on those wires and burned up (maybe not literaly burned but caused high resistance through amp draw) the stock wires at some point along the way. Check the voltage it should tell the tail.

 

[branndon_b]

a guy i work with has a suburban, and he went through several fuel pumps too. turned out he had a weak grounding problem. think they ran new dedicated power to the fuel pump and he's been problem free for over a year now. just something to check into.

 

[Korn]

a guy i work with has a suburban, and he went through several fuel pumps too. turned out he had a weak grounding problem. think they ran new dedicated power to the fuel pump and he's been problem free for over a year now. just something to check into.

How did they run the dedicated power wire, did they hook it to exaclty. Thanks.

 

[retorq]

If its low, just saying if its low, then why would the Airtex pump work the other wouldnt. Im goint to test it when I get it back home from town.

Mine worked cause the way the wire was, when I got in there and started moving shit around I either grounded it or pulled it completely apart. That's my theory anyways.