replaced fuel pump, still won't start

Might be bad FP relay

Did you check for voltage on gray wire at fuel tank/pump with ignition on ??

Not sure where relay is on that model, should be one with a gray wire and orange wire plus 2 other (green/white maybe ?) wires.

Orange is hot all time Gray is feed to pump

If no 12volts at tank with ign on, try unplugging relay, jumper orange to gray, pump should run.

If no volts on orange wire, then fuse maybe blown.

I'm fighting my 94 s-10 blazer, same issue

If I'm not mistaken, the FP relay in on the FP. The portion that sits exposed on top of the tank. If I replace the entire unit that includes a relay, it should have solved the relay issue. I checked all fuses. They're fine. Thanks for your help. Maybe injectors are clogged?

The relay is under the hood, mounted to the firewall. Sounds like you have a bad harness or a bad power feed.

i agree check power at the pump,fp relay check..id also check injector with a ohm meter..

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Is there anything that leads you to believe it's not the oil pressure switch? I saw a few posts the said the OP switch shuts off the fuel pump in there's no oil pressure. thanks for all of your advice.

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The OP switch is meant to kill the FP if the engine was running and then stalled for any reason, mainly a safety item in case of accident/wreck, the pump won't sit there and pump fuel out a broken fuel line. So a defective OP sw might keep an engine from running, but should allow it to start, at least for a few seconds.

I don't know if the 93s have this jumper or not but on the driver's side fender under the hood there might be a little red wire with a connector or bare end on it. This bypasses the fuel pump relay and jumps 12V right to the pump. It isn't a good idea to leave it connected to long but it makes it easier to test than running a lead from the battery to the pump. If you can't find a test lead then run a wire all the way under the truck from the battery to the pump connector itself. If it powers up, you have an electrical problem. My guess would be the relay. Try swapping the relays under the hood to see if you can get it running. On my 95 the relay for the pump is in the glove box 2nd one in. I think on your 93 it's under the hood and 2nd one in. This should be an easy fix. It could also be a bad ground at the pump. See if you can trace the ground and test it to see if it's ok. If not, clean up the ground contact points or replace the harness/wire. It could also be an ignition switch I think I've heard of this causing similar issues before...

Good luck. Andrew.

You may thnk this is a stupid comment/question, but do you have power to the headlights? Had a similar problem with a fuel pump on a 91 S-10, changed it, then found no power going into it, Turned out one of the blade connections for two hot wires from the engine harness to the fuse panel was bad. Took forever to figure it out

I had the same problem with my 95 Silverado..It was the ignition switch..Have you scanned it for codes??

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Hi Brian.

Like the others, I think its the fuel relay. On the firewall, next to the overflow tank, is a black cover that has the fuel relay in it. Switch it out. And like the others have said, check the ground.

Let us know your current status.

HDS.