Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
at the fuel tank connector when cranking it over with a meter does the grey wire show 12 volts at the tank ?
if that has 12 volts at it can you be sure the big black at the pump connector is a confirmed good ground
if not run a new ground from the frame to the connector
Going to work
He said what your describing and what you sent is exactly what he thought. Something wasn't getting enough air or fuel.
so the grey does NOT have 12 volts cranking it over ?
if that is correct pull the fuel pump relay out and with the key OFF how many terminals in the box show 12 volts that the relay plugs into ?
# 30 should be 12 volts all the time then it is jumped through 87 which is the grey wire and sends the volts from 30 to the fuel pump
does the ECMB fuse show 12 volts on both sides of it testing that fuse in place through the little openings in the tops of that fuse ?
no 87 is the grey wire that goes to the fuel pump
if you jump 30 to 87 in the box will the truck run and the fuel pump run ?
no 30 is supposed to be 12 volts which you tested it showing 12 volts
jump 30 to 87 will the truck and fuel pump run ?
with it jumped does the grey show 12 volts at the tank connector ?
Hi Im David, so you can get the fuel pump to run by jumpering the fuel pump relay? correct?
with the relay jumped you had 12 volts at the pump? or without the relay jumped and the key on?
ok pull the jumper , turn key on and check for 12vdc on another pin on the relay base. you should have 2 positions that get voltage (one will have it all the time, 1 will have it with key on) make sure that happens
what engine you have?4.3?
heres a print for us to work from
should be 83. theres 4 positions. correct?
so 30 87 83 85?
let me know tomorrow when you're ready
youll know, when you have 12 volts with the key on. if you dont then we got issues to look into
ok then thats a problem...... let me look into it
you have either an open wire from the fuel pump relay (dark green/white wire to the PCM or possible a problem with the ignition switch, im trying to find the wiring for the ignition switch tie in.
sure, if its bad.
gimme a few to find that wiring print
ok... im still looking
check the black wire at the relay to ground. make sure its a good ground
just checking in to see how its going
ok. let me go back over our notes
so we still have no pump operation correct?
jump 86 to 30. key on
you going to have to check continuity from the relay to the pcm.
that pcm isnt putting out the control voltage to the relay.
ok my friend