jackmo

I have a 1996 3/4 ton chevy truck 4 wheel drive 350 motor.It is not fuel injected it has a throttle body

I changed the tank, fuel pump. The truck ran good for a couple of weeks now I have no fuel pressure. I replaced the relay still nothing.

Does this truck have fuel pressure regulator?? if so where??

Thanks,
Jack

MDTAHOE

The regulator is built into the top of the t-body (the fuel metering body) it will not cause no fuel pressure. Just because the pump is new does not mean it is good.

jackmo

I know the relay turns the pump on & off but what triggers the relay?

Thanks,
Jackmo

MDTAHOE

I would bet the pump or the sending unit has gone bad. Put your hand on the relay and have someone try to start the truck, if you feel the relay click it is not the problem. You can pry the black top off the relay and manually close the contact with your finger if the truck starts then you need to look into relay control problem (very,very rare).

Biggie360

you could always bypass the relay while monitoring the fuel pressure. if the preassure goes up like it's supposed to, then your pump is A ok, and the problem is further back. if not then either your pump is dead, or there's an electrical problem somewhere in the battery, pump, relay section of the circuit. A quick poke around with a voltmeter will help steer you in the right direction.

jackmo

I haven't had the time or good weather to work on this.

What I have now is sometimes it works sometimes it doesn't!

The battery is fully charged & the engine turns over good.

The relay doesn't move at all when I turn the key on.
If I remove the relay I get 8.25 volts on the middle wire at the plug to ground.
I can hear noise at the t metering body.

Any ideas??

Thanks,
Jackmo

Biggie360

well, to start with, are you 100% sure that the problem is fuel? if yes, then just go find the hot wires for your fuel pump, and "hot wire" it. if it works, and you get fuel pressure, the pump is fine, if not then it needs replaced. if it works then next I'd check the fuel pump relay(this isn't that hard, if they're the same size and style, just switch it with the A/C or headlights and see if that works) if the relay is bad, then replace it. If the relay is ok then... we'll get to that later...