So in my quest to get this old truck running (90 4x4) I changed the computer the other day. Now when I turn the key on lots of things go click which sounds right but there's no fuel pressure. There's a click back at the fuel tank but no "whirrrrr" like a running pump. Does this sound like a bad fuel pump? Am I just hearing a relay?

 

check the splices under the PDC; they are known for corrosion. Double check the relays for the fuel pump and the ASD. Make sure everything is connected properly w the PCM (disclaimer: i havn't worked with a PCM at all so I don't know if you can hook things up wrong)

If you are hearing a pop by the place the fuel pump is at and no whir sound that would concern me a tic as well. the easiest thing to do w the fuel pump is to pull the bed off to replace it instead of dropping the tank. if you go to that point you can use a mulimeter to check the voltage at the pump.

Good Luck, keep us informed!

 

I'm trying to avoid that if the pump is good is my point. If I'm hearing a click at the gas tank that means an electrical signal to the pump is present therefore the issue is, should there be a whirring noise too. Apparently on a 1990 there is no pcm and splice like a 1992-1995. I'm asking to avoid unnecessary work. Kind of like going to the doctor and diagnosing a health problem before cutting rather than just performing exploratory surgery to find problems.

 

Hmm. I dont know how much stuff is on top of your engine. But I just pulled the fuel line off the injectors (i know, your is carb) and ran the line into a cup and then crancked the engine. No gas = bad fuel pump or clogged fuel lines. If you do change the pump LIFT THE BED!!!! You can find videos on youtube if you wanna see it done. Its much easier than getting that damned fuel tank back up in there.