I have a 78 short bed and i'm not getting fuel to the carb. What are my probable causes & what do i need to check? Where is the fuel pump relay & when does the fuel pump make sound? Any help would be appreciated.
ist the 78 a mechanical fuel pump? its located on the side of the head right in front of the motor...
78 has an in tank electric pump, relay is under the dash near the steering column, pull the wire off the oil sender on the side of the block next to the oil filter, turn the key on, and you should be able to hear the pump running by listening at the fuel filler neck or by pulling the fuel line off under the hood at the filter to see if any gas is pumping. The pump is wired through the oil sender as a safety measure so if in an accident and engine dies or the loss of oil pressure the fuel pump stops pumping.
ok. did all those things and still no fuel or sound from pump. as soon as you turn the key to the on position you should here the pump running correct? have gas in tank and new fuel filter. should i check continuity? replace relay? i want to try everything before i drop the tank. what should i try next
Make sure you have a good connection at the fuel pump and the relay. If theres corrosion you wont get a full contact nor will you get all the power needed. so check that and if the connections are tight and clean then get out your volts/ohms meter and start checking with the key in the on and off position
Have someone crank it and chk if you hear the pump. You can also use a test light to chk if the wire for the pump even has power during this process... Some pumps don't come on at the key "on" position, it has to be cranking... Some electrical circuits especially for fuel pumps are wired to the alternator somehow and the alternator is the last piece in the circuit... I know for a fact this is how Isuzu's work... Just thought I'd throw that out there...
dropped tank and was full of crap. fuel pump was shot. checked power at pump power and nothing. i have power from ignition to wiring harness plug in the engine bay. unplugged and checked continuity through the power wires leading down to the pump. nothing. going to follow wires down and see. anything else i should do? thx for all the help
