priming but not pumping fuel pump

Hello, did you check for codes? Did you check pressure with a gage? If you have TBI can you see the injectors spray, even a good spray pattern doesn't mean the pressure is good.

It shows you have an oil pressure switch in the fuel pump circuit, a redundant power supply to the pump, once you crank enough to bring up oil pressure, the pump should run, even without the rpm signal, but the injector/s won't pulse., without the rpm signal.

With the fuel pump prime connector, you can run the pump without cranking and check pressure.

thanks for the reply. i actually decided to dump out the old gas, and try new gas since it was sitting for a year before i drove it home. with that, the pump started pumping, through the filter, but it still won't start.

i haven't checking the pressure anywhere, but i think it must have been the old gas that was messing up the new pump. i was planning on cleaning the injectors to see if that's the problem.

new starter, and it's cranking but still not firing.

Did you ever check for spark at the plugs, with engine cranking?

went out to check the spark, and tried starting it first. it started, but no guages worked (fuel, speedometer, temp). i shut it off and restarted, and it was ok, but temp guage was maxed out. let it sit for about an hour, and now it won't start at all again, but it's still cranking.

sound like something simple?

Maybe I misunderstood your post, you don't need spark to crank it, but, you do need spark as well as other things, to start it, get it to run. Check for spark when it refuses to run.

no, it has spark. when i dump fuel into the injectors, it starts, and stays running. but if i turn it off and restart it, the injectors aren't spraying and the pump continues to prime and won't shut off. i took the top part of the injector casing off and cleaned it, but it still isn't working. so, it's either the injectors or there is this valve in the cover that's spring loaded that i guess could be it.

If your saying the pump runs with the key off, check the oil pressure switch.

Use a noid lite on the injector plug, see if there is a pulse with the engine cranking? The lite should pulse.

the injectors will spray if i pour fuel into the throttle housing to start the truck. but if i turn it off and try to restart it, they won't spray and the pump just continues to wind, but won't shut off. have to pour gas back in to get it to idle.

went to the junkyard and replaced the whole injector housing with a used one, and still nothing. pump still just continues to prime and won't shut off, and it won't start.

new injectors are expensive so i'm trying to avoid buying them until i have to.

where is the oil pressure switch?

This info is for an 89 s10 4.3.

ok thanks. i'm pretty much down to that, the fuel pressure regulator (which i'm also not sure of the location) or the injectors. oil pressure regulator is the cheapest, so i guess i'll start there.

either way, it'll have to wait til next week.

thanks. any idea where the fuel pressure regulator is, or whether one that isn't working would cause a problem like the fuel not getting to the injectors when i'm starting the truck?

have the same problem did you everget your problem solved

Did you replace the fuel pump relay? Here is a guide to help you test it:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Please run down this guide and report back.