1985 Ford Ranger 2.3L fuel problems?

[CDW98]

I've been stuck on this for a while. I have replaced the fuel pumps, new filter new gas tank. the truck primes up and starts but wont stay running it slowly just dies down from fuel lost I'm guessing. It will start again but the system has to be re-primed. the fuel pressure regulator has been replaced too, I don't know what else to do.

 

[tomw]

Do you have two pumps? One in the tank, a 'lift' pump, and the second on the frame rail just about underneath the seat? I do. I also have a canister type fuel filter just behind the hi-pressure pump on the frame.
If the lift pump quit, maybe the high pressure pump runs out of fuel, or the high pressure pump is dying. Or the filter is blocked, and will allow slow filling of the canister[referred to as the 'accumulator' in later models] for slow running, but not allow enough flow for higher speed operation.
If you have never replaced the canister filter, it may be your solution. Or the pump you did not replace if you have two.
If you have a different system, check the fuel pressure regulator on the fuel rail feeding the injectors. It has a vacuum line that you can disconnect while the engine is idling that should cause pressure to rise, and when re-connected cause pressure to drop. It could also be failing closed, but unlikely.
tom

 

[RonD]

Yes, ^^^

Get/rent a fuel pressure gauge, so you can confirm what you think is happening, is actually happening.

Also, the computer may be shutting off the fuel pumps after engine starts or doesn't turn them on at all after priming.
Computer controls the Fuel Pump Relay, it is located on passenger side inner fender, closer to firewall.
When key is turned on the computer closes this relay for about 2 seconds, priming the system, computer won't close this relay again until engine starts, or you turn off the key and turn it back on.
Computer gets "pulses" from TFI distributor that's how it tells the engine is started.

You can test for this by manually closing the fuel pump relay using a jumper wire.
Look here: http://www.therangerstation.com/tech_library/OBD_I.shtml

You will see a diagram of the OBD I(VIP) connector, usually located on the drivers side of the engine bay, near firewall, but can be on passenger side.
You will see the Fuel Pump slot IDed in that diagram.
If you put a wire in that slot and Ground the other end the Fuel Pump Relay will close and stay closed as long as the key is on.
If you use the jumper and engine stays running then you have a problem with the computer or a problem with computer "seeing" pulses from distributor, i.e. computer doesn't know the engine is running.

The Fuel pumps run all the time when engine is running, they don't cycle on and off, so you can drive the truck with jumper in place, it is just a safety issue in case of a fender bender, if a fuel line should break, the engine shuts off from lack of fuel so computer would shut off the fuel pumps, with jumper in place the pumps would stay running until key was turned off, so you could end up sitting on a big pool of gasoline.........................never a good place to be

There is an inertia switch in the passenger footwell that cuts fuel pump power in case of an accident or roll over, jumper doesn't effect that safety switch, pumps would be off if that switch is tripped.

 

[CDW98]

It sounds like that might be it. Could I just straight wire the fuel pumps with toggle switches or would that not solve this problem?

 

[RonD]

You could just run a wire from that OBD I slot into the cab and use switch to Ground it in the cab.
No muss no fuss, no fuse needed