Mechanics

FUEL PUMP RELAY??? CHEVY K1500

1990 GMC C1500

I was driving on the beach one day and the truck cut out and off. Through process of elimination I found that it was a fuel problem. First I checked the lines and found some kinks and a crack but no leaks and didnt hear my pump running. I had to buy a new gas tank when I went to install my fuel pump because of rust. The lines from the sending unit actually broke off when I dropped the tank because they were rusted so bad. I of course installed a new sending unit also. I found that my fuel pump fuse was blown so I changed it. One of the guys with me when it happened decided to cross my wires before the fuse to do a " smoke test" and then shorted something deeper in the system. I created a temporary alt. Hot to the pump to isolate where my problem was and the pump would run and the car would try to start. I sounds like its not getting enough fuel pressure at the TBI and when I watch it come out of the injecters it doesn't seem to spray the way it should. None of the lines leak, and when I bypass the relay the fuse doesnt blow. What does the relay do and if it is bad would that be the reason my pressure is deficient? Is there a certain hot that pressurizes at the injector plugs on the TBI? Does it make a difference if the injector plugs are switched?
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Kriswaselich
April 13, 2006.




The fuel pump relay acts as fuel primer for between 3 and 9 seconds. The circuit is completed trhough the oil pressure switch when oil pressure comes up. If you are direct wired and the pump doesn't function replace the pump without question. Let me know

Tiny
Losone
Apr 14, 2006.
I already changed the fuel pump and I found a good fuel relay off a junk suburban and now the fuel pump spins constantly, no fuses blow, but the TBI is not getting any fuel. I tried turning the key on and off to let the pump run but it doesn't even seem to fire a little. It cranks over at a normal speed. I had to change the top of my TBI because when I changed the lines I cross thread and stripped the holes in the back. I changed the gaskets and cleaned out the injectors real good with kerosene. Before this fuse problem it was spraying strong. Yesterday before putting in the new fuel relay it still flowed from the injectors but with less pressure. Now today nothing. Where is my oil pressure switch and does it matter if I have an oil leak?

Tiny
Kriswaselich
Apr 14, 2006.
The presure regulator is in the throttle body. It is the hump on top. Parts stores sell a rebuild kit that is not expensive. On the other hand the used pump might be bad or some trash in your filter. If I was there I could put my hand on the problem. I have fixed hundreds. Good luck
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Tiny
Losone
Apr 14, 2006.

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