Ok last week I posted about my truck suppposed fuel pump going out. I swapped out the fuel reley with the horn reley and didn't hear the fuel pump and still wouldn't start. So this Saturday I bit the bullet and bought a new fuel pump and put her in thinking that would take care of it, it didn't. I got my friends test light to see if I have power to the fuel pump and I have nothing. I rechecked the releys and all of my fuses to no avail. I also pulled the ground cable off to try and reset the computer, that didn't seem to help either.

Did I miss something? I was gonna hot-wire the new pump but I dont want to hurt the new pump or anything else.

What's my next step?

 

tough one. I am kind of guessing here but I would imagine it gets it's signal and power to energize from the ignition cylinder. to diagnose I would probably try twisting the key many times with different angles of input(hand pressure on cylinder). to try and make a connection internally that has been worn a bit. also check out the ASD (Auto Shut Down relay/circuit) kills fuel in an accident. don't know much about it but there is info on it in this forum.

 

Ok. Thanks for giving me an area to look at. I was thinking the ignition switch, but I didn't know if that might be it. I'll dive into forum search to find out about the ASD reley. Again thanks I was out of any good ideas.

 

ASD does nothing with the fuel pump relay only the injectors/ignition coil sometime o2 heaters. Have u tried pulling the fuel relay and run a little jumper from pin30 to 87? Pump will be running with key off all the time.

 

use the advanced search option - for posts in 2nd gen ram, by cmckenna with keywords: fuel pump pressure test

he wrote some extremely detailed procedures that might help you.

 

Well I checked out those posts by CMCKENNA and I am wondering if a bad crank sensor cause me to get no voltage to the plug of the fuel pump? When I pulled out the old pump I hot-wired it to my battery and it ran fine. My fuel pump fuse tested fine and I swapped out my releys Which didn't help. But a co- worker said something about the crank sensor causing a hard starting condition that I was living with for sometime. Could my crank sensor do this?

 

Fuel pump relay is controlled independently from the ASD relay. That's not to say if the PCM decides to release the ASD relay, it won't do the FP relay as well.....

In any event, make sure you are getting power TO the FP relay. You should have 12 volts on pin 30 all the time.... via fuse 8 in the PDC. (20 amp) The control circuit is fused by fuse 9, in the fuse block on the side of the dash.

 

Ok.. I'll check the voltage to the fuel pump fuse when I get back from work on Friday ( I hate working out of town). I will also make a jumper for the fuel pump reley as well to see if I can get it to work as well. I know tha I had voltage to the fuse, but no idea as to the reading.

 

So if pn 30 has power all the time and pin87 is the fuel pump powr supply then yes jump pin30 to pin87 in the power block to get the pump running. If it doesnt come on then theres a wire break from pin87 to fuel pump. Could be wrong any thoughts?

 

That seems perfectly reasonable to me.