Help-no fuel pressure

[DezlWezl]

My fuel pump seemed to stop working last week-truck starved for fuel and died. I replaced the pump, and it worked great for a week. Tuesday night it did the same thing and cost my boss a huge tow fee. I have replaced the fuel pump relays behind the dash. The pump is damn near brand new. The emergency shut off is not popped up. I have a pre-pump Dahl filter and a fuel pressure gauge on the test port. Nothing. I drained the Dahl, and it was siphoning off the tank as usual-so I've got good, tight flow from the tank. Now the fuel pump won't do anything. What else could it be-just a bad wire, connector or what. When it first did it, I got P0231-fuel pump secondary circuit low. I haven't been able to get it to another code reader to see if anything else comes up. Could my ECM be bad? Help, I need this truck tomorrow night. I'll try to check some wiring with a multi-meter.

 

[DezlWezl]

My fuel pump seemed to stop working last week-truck starved for fuel and died. I replaced the pump, and it worked great for a week. Tuesday night it did the same thing and cost my boss a huge tow fee. I have replaced the fuel pump relays behind the dash. The pump is damn near brand new. The emergency shut off is not popped up. I have a pre-pump Dahl filter and a fuel pressure gauge on the test port. Nothing. I drained the Dahl, and it was siphoning off the tank as usual-so I've got good, tight flow from the tank. Now the fuel pump won't do anything. What else could it be-just a bad wire, connector or what. When it first did it, I got P0231-fuel pump secondary circuit low. I haven't been able to get it to another code reader to see if anything else comes up. Could my ECM be bad? Help, I need this truck tomorrow night. I'll try to check some wiring with a multi-meter.

Talked to a co-worker who thinks a body ground may have been disconnected and not connected when they rebuilt the tranny. This could burn up the pump, and it did happen when he was test driving it from the rebuild.

Possibly low voltage burning up the pump? I discovered in all this that I had one bad battery and one questionable one. I've replaced them. I'll run 12V straight to pump to see if pump is indeed bad. I got P0231-fuel pump secondary low code when it was at the tranny shop. Maybe that's it. HELP!!!

 

[DezlWezl]

Talked to a co-worker who thinks a body ground may have been disconnected and not connected when they rebuilt the tranny. This could burn up the pump, and it did happen when he was test driving it from the rebuild.

Possibly low voltage burning up the pump? I discovered in all this that I had one bad battery and one questionable one. I've replaced them. I'll run 12V straight to pump to see if pump is indeed bad. I got P0231-fuel pump secondary low code when it was at the tranny shop. Maybe that's it. HELP!!!

UPDATE: Not the pump. I bypassed the relays, etc. and the pump works just fine. I now have it rigged to be driveable with a switched source from the fuel pump 20A fuse. I need to find a source that is only on when the key is on in case I forget to flip my switch. It does, however give me a kill switch feature, but I no longer have the emergency pump kill in the loop.

 

[imelmo]

Wish I could help. I had the fuse go out on my SX pump a week ago and it scared the crap out uf me. Obviously, that's not what's wrong with yours.

 

[holtzer1]

best thing to do is get a wiring diagram and trace down the REAL problem. the jumper wires you got going to it may work good for now, but it would definitely be best to find out what is wrong with the original wiring.