No fuel pressure after fuel pump swap

Hi,

When the key is turned "on" with out the engine running, the control module turns a fuel pump relay "on" for two seconds. If that relay doesn't energize the pump to prime, a delayed start or even a no start can occur. Lets start by testing the relay. The fuel pump relay is under the hood in the fuse/relay box. I attached a pic to help locate the correct relay. If there is another relay with the same part number, switch them and see if that makes a difference. Or, here is a link explaining how to test a relay:

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

My biggest concern is that the relay is working when the engine is running. This may be related to the control module, but lets start with the easiest fix first. Also, I will need to know if the oil pressure switch is working.

Let me know what you find.

Joe

Joe, thank you for this great starting point. Besides the relay itself, are there any fuses I can check, I wonder? I have ordered a test light and will see to the relay. I expect I will have an answer towards early next week. In the meantime, no, there is no sound when the key is turned on. No click at the relay, no priming noise at the pump. Funny thing, before the fuel pump was changed this truck started POW first crank. Runs great once I use starting fluid. Thanks again!

Let me know what you find. The interesting thing is that it runs once you prime it. Have you tried checking for diagnostic trouble codes? Also, if possible, can you check for spark to the plugs when it fails to start? Also, does the oil pressure gauge work?

I don't have a diagnostic trouble code device, sorry. Yes, spark to plugs when fails to start. I will check the oil pressure gauge and reply back this week. Thanks for tips and tricks and great info!

Incidentally, does anyone know what fuses could come into play besides the relay itself? There must be a fuse to something that I can check?

Hi,

It's in the under hood fuse box. See the two attached pics. Note that the numbers in pic 1 are looking at the box from the rear. The second pic shows the actual fuse location.