What do you know. problems with a 3v. Im new to this forum so im just going to state what im having issues with. First of all tjis truck was an abandoned vehicle. had the ignition taken out. But i just got the thing to start and run, only a cirtain way. Ive got it jumped at the diognostic from B to fp. only way to get the fuel pump to stay on. + it wont run if the vafm is plugged in. I unplug it. starts up, as soon at it makes connection again it dies immediatly. aaand last thing. when i first try to start it it takes me like 6 tries to get it to continue running. Start- stall start-stall etc. it cuts out. Reealylly bad it high rpms.. and im by no means a machanic. pleaaase help im starting work soon and need help

 

Replace the VAFM. It's not meant to run well without one that works.

Then go from there.

 

There's a signal from the VAFM to the Circuit Opening Relay (COR) that hides just above your ECU on the passenger's side kick panel in the cab. If that's not getting the signal, the fuel pump won't run, which is what you are experiencing. Jumping B+ to FP bypassed that relay.

Check your VAFM with a multimeter first: http://personal.utulsa.edu/~nathan-b...92volumeai.pdf. In not in spec, replace.

If it checks out ok, verify your COR is working: http://personal.utulsa.edu/~nathan-b...96circuito.pdf. If not, replace.

 

Don't drive around with the jumper between FP and B+. If you get in an accident that breaks a fuel line, you want the fuel pump to stop as soon as the engine stops sucking air, and not a second later. With the jumper in, you've defeated that safety measure, and it could end in a fiery death.