Truck Repair: 97 Chevy C1500 6cyl 4.3, oil pressure switch, crank sensor

Question
Van,
I sprayed trottle Body cleaner in the Trottle and the Truck started right up. I left it run for about 35 minutes and then shut if off I tryed to start again with out the spray would not start. When I sprayed it it started right up again. Left it run again for about another 30 minutes. I turned it off tryed to start it again would not start even with the spray I am gonna try it again to night. Do you think it could be the relay. Because when it starts it runs great.

Thanks
Dave

Answer
Hi Dave,
it could be the relay, or something that operates it.
The fuel pump is operated by the relay, but the relay is controlled by the ECM, using a crank signal, so it won't keep running if the engine isn't turning over.
But there is a redundant system, which is an oil pressure switch, which also supplies battery voltage to the fuel pump for as long as there is at least 4PSI of oil pressure.

it sounds like your truck is starting on the spray, and developing oil pressure, and the pump is then running on the power from it, which is fine.

But you may have a bad crank sensor, fuel pump relay, or ECM.
I doubt it is the ECM, so concentrate on the other two, but also check the wire connections.

Van