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Discussion Starter #1
Hey everyone,
I posted here a while back I have a 2002 Chevy S10 Xtreme and I was having a fuel issue (potentially). The truck broke down on me while I was driving. Before that it was stalling and then finally it stalled for the last time and never started again. When I turned the key I did not hear the fuel pump Prime so I replaced it. With the new fuel pump I ran power directly to test port and the pump worked it even sent fuel and pressured up because I was able to release the pressure from the Schrader valve.

I have replaced the fuel pump, the relay, fuel / oil pressure switch and even the ECU. For some reason the truck will not Prime the fuel pump whenever I try. I feel like I have tried everything and I still can't figure it out. The engine does crank. I believe I may now actually have an issue with my spark plugs because the car will not start with starting fluid either at this point. That being said, what the heck can be happening? Why wouldn't the fuel pump Prime when I turn the key but will power on when I run power directly through the fuse box test port? Could the fuel spider have something to do with this? I have to be missing something. I have now owned the truck for a few months and it has done nothing but sit. I would very much like to drive it.


If anyone could please help me I would be extremely grateful. I'm desperate here! I could really use some Direction and advise. Thank you for taking the time to read!
 

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Administrator
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22,267 Posts
Guessing you have a 4.3, so I. moved it there. If that's wrong, let me know.

Your new pump should have come with a new harness. Did you connect the wires according to the instructions? Different trucks/pumps are wired differently....meaning if you have the same colors on the new harness as the old...it may not be wire to wire color.
 

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Been there Done it
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7,505 Posts
Have you checked every fuse in both panels?
Are you getting 12V to the fuel pump relay?
One possibility is the ignition switch. Which if defective may not be providing 12v to either the fuel pump or ignition but could still crank the starter.
Doubt the spider is a problem.
 

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Have you tried starting it with power run to the test port (since you said the pump runs that way)?

Also, my Blazer didn't run when I bought it. The previous owner had thrown a bunch of parts at it, including a fuel pump, MAF sensor, ignition coil, and a bunch of other stuff before deciding to sell it out of frustration. The problem turned out to be a bad ignition rotor. It had a tiny hole burned through it, which caused the spark to go to the distributor shaft instead of the spark plugs. You may want to check that.
 

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Engineer, Member SAE
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Guessing about mechanical parts is over. Time to become best friends with a volt meter. Harbor Freight. $6. Measure at the pump terminals, 12V?

I think thats grounded back at the tank, also check that the pump has a ground back to the battery. Chassis grounds get corroded.

There must not be power back there as the pumps not running. Pull the relay and test for voltages on the relay socket. There has to be 12V on one coil terminal and at least one contact. Youll need a wiring diagram. Beyond that, its bad under-hood wiring or an ECM problem, whether its bad or missing some sensor input I cant even guess at. A missing sensor should set a MIL code.

PS you cant be a good mechanic unless youre at or slightly beyond your wits end. Dont sweat it...its been said that the great top fuel mechanics were half nuts due to chemical exposure.
 

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I finally got blown
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If you swapped ecm/pcm it may be in theft mode. But if it was it should still run for about 3 seconds. Make sure you have full battery voltage. Maybe take jumper cables and clamp to the negative of the battery and the engine block and see if it cranks then. If it does you have a bad ground. If it doesnt maybe you have a bad starter or ignition switch.
 
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