2001 Chevy S10 P0102 Code: Diagnosis and Next Steps for No Start with Zero Fuel Pressure

P0102 typically does not prevent starting — it often appears after the engine has been running and is triggered by sensor input issues. It may activate when attempting to start, especially if there's a vacuum leak or faulty air flow readings. When you turn the key to 'On', you should hear the fuel pump run for 2 seconds to prime the rail. Do you hear this? Check for spark using a spark tester. What is your measured fuel pressure? It should be between 60–66 psi. If there's no fuel pressure and no pump sound during ignition, then the issue lies in the power circuit — check voltage at the fuel pump relay terminals. Try carb cleaner to spray into the intake; if it starts briefly, that confirms spark and points to a fuel delivery problem. Please share your results.

The engine starts with starter fluid for a few seconds — this confirms ignition is functional. There is absolutely no fuel pressure (O-pressure). I tested the pump with a fuel pressure gauge and confirmed it does not produce any output. I replaced the pump, then tested the old one — it worked properly. I’ve already checked relays and fuses, all of which are fine.

When you turn the key to 'On', do you hear the fuel pump run for 2 seconds? You must verify voltage on the gray wire at the back of the truck — specifically in the start position. This is a critical step to confirm whether power reaches the pump.

No, I do not hear the fuel pump run. I even removed the fuel filter and tested it — no change. Someone suggested the crankshaft sensor might be faulty. Could that be the cause? Or is it possible the pressure control valve (attached to the rear of the spider injectors) is malfunctioning? It seems like there's no power reaching the fuel pump. Grounds are fine — tail lights work normally, so the ground circuit appears intact.

The fuel filter has no impact if the pump isn’t running. If starter fluid allows the engine to start and run briefly, that confirms ignition is working and the crankshaft position sensor is functional. You stated you don’t have power to the pump — either you do or you don’t. Do you have a digital multimeter? Check voltage at the fuel pump relay terminals directly. A proper circuit check will help isolate whether it's a wiring issue or faulty relay.

Remove the fuel pump relay and use a test light connected to battery negative. Touch the positive terminal of the battery to each terminal on the relay. With the key in 'On' position, one terminal should light up. Have someone crank the engine — during cranking, the test light should illuminate on another terminal for at least 2 seconds. Post your results so we can proceed with diagnosis.

I followed the instructions: one test light lit when the key was in 'On' position, and another lit during cranking — it stayed on until I turned off the key. I began checking the gray wire leading to the fuel pump. I can confirm power up to a certain point, but I’m unable to access the full length of the wire due to the truck bed being raised. There is a fuel vapor vent pressure sensor mounted on top of the fuel pump — my new pump didn’t include one. I used my old pump’s sensor. Could this be causing the no-start condition? I apologize for the earlier confusion — I was testing the wrong wire and only realized it after lifting the bed up. I now understand that there is indeed no power to the pump, which points to a wiring or relay issue.

No, the fuel pressure sensor on the vapor vent line does not cause engine failure or prevent starting. You must verify voltage under load — specifically on the gray wire at the rear of the truck — to confirm if B+ power is reaching the pump.

Did you replace the fuel pump relay correctly? Make sure it’s installed in the correct position and not swapped with another component.

Yes, I replaced the fuel pump relay. The horn and fuel pump relays share the same part number — I tried installing it in the horn relay slot, and it worked. I also tested the fuse with a known good one. Additionally, when turning the key on and off, I hear a clicking sound from a solenoid near the idle control valve. This may indicate an issue with the idle control system or related circuit.

You must check voltage on the load side of the fuel pump relay — specifically on the gray wire at the back of the truck — to confirm if B+ power is being delivered. This will determine whether the issue lies in the wiring or a faulty component.

I had the same problem with my 2001 Chevy S10 4.3L. If you're still experiencing this, I strongly recommend checking the ground wire that runs from the fuel pump — it’s a common source of failure and can cause intermittent no-start issues.