94 2.3 fuel problem

racsan · #1 02-01-2018, 04:31 PM

every so often my ranger would not want to start, i sometimes could get it to go by using either or putting a charger on battery for more boost, makes no sence cause its a new battery but thats what was happening, mostly when it was really cold out. well now it wont start at all, will fire off of the either but one the either is used up thats it. i do hear noise from the fuel pump area when key is first turned on, like its building pressure then shutting off, but theres no fuel at schrader valve on fuel rail or underneath when i took line off of back side of fuel filter. i bypassed the shut-off inertia switch and that did nothing, i do think pump must be dead, not sure why it makes noise like its pressurizing then clicking off but no fuel at fuel filter. is there any in-line pump i could buy to put underneath? bad time of year to pull the bed, must have 300# of stuff back there right now, cant drop the tank, its a 20 gallon from a '97 and while its securly mounted, its not really possible to drop it- and its full of fuel. if i have no choice but to put a new pump in tank, whats the best one? i damn sure dont want to do this again..... miss the days of a engine mounted pump that took 2 clamps, 2 bolts, 30 bucks and about 30 min to swap out...

tomw0 · #2 02-02-2018, 06:37 AM

If you look under the cab, right below the floorboard feet rest area, you should find a pump attached to the chassis. The older models had two pumps, one an in-tank 'lift' pump and the second, a high pressure pump on the frame under the cab.
I *think* you have one just about under your feet that does the whole thing, lift & pressurize.
The pump relay is energized when the key is first turned to ON, and then de-energized and under the control of the ECM. The ECM looks for continuing ignition pulses to know that the engine is running on the old system, and should look for CPS -crank position- signals to know the engine has started, and then re-energizes the relay.
You should be able to jump the power terminals in the relay socket to energize the pump 100%. If it doesn't run & make noise, give it a thump with a rubber mallet equivalent, and if it takes off, you need a new one. If it doesn't, and there is power to the terminals, you need a new one.
tom

blkpnthr · #3 02-02-2018, 08:13 AM

I can tell you that on a 93, it is absolutely not a frame rail mounted pump. The 2 piece lift+pressure pump system is a relic of the 80s, used on Fox platform cars and trucks to a point...by 93 it was gone. When it disappeared, so did externally-mounted fuel pumps. In that case, there is only one pump, and it's in the tank.

There is typically a short rubber fuel hose that connects from the output of the fuel pump to the metal pipe that is part of the fuel pump hanger/sender assembly. If that rubber hose were to come off or split (and it does happen), the fuel pump could run all day long and never pressurize the system because the fuel would just be splashing around inside the tank getting shot out of the pump.

You have verified that as far back as the filter, there is no fuel. The next step unfortunately is to get in the tank and see what's up in there.

You could try making a short jumper wire to "hotwire" the fuel pump relay (careful with that, if you connect the wrong terminals you could toast the computer), which would make the pump run constantly until you remove the jumper wire. This would give you the opportunity to go put your head under the tank and verify 100% that you hear the fuel pump.

I'm not sure if the rotor/vanes of the pump can come loose from the motor shaft, that could explain it also (motor spinning but not moving any fuel). Defective fuel pump in that case.

tomw0 · #4 02-03-2018, 07:17 AM

If the 93/94 has the original EEC-IV connector, you can jumper the pump to energize the relay between two terminals.(provide ground for the relay winding, she runs)
Sooo, the original mess with two pumps went to one pump and then to an in-tank setup. I did not know that.
If the in-tank pump is toast, I would sooner raise the bed than drop the tank, and would recommend that alternative. The bed does not have to come off the frame totally as you can just lift one end and prop it up for access.
Is there still a 'filter reservoir' housing in the 93/94 models? The plastic assembly with two inlets and two outlets remained for a while, even though it did not house the filter any more. It's quite the process to change the filter element if you have one.
tom

racsan · #5 02-09-2018, 08:38 PM

well the stock pump was indeed dead, ive tried something and so far its working, a msd 2555 inline fuel pump, 45 psi. mounted it right along side the fuel lines near the fuel filter. in fact now there are 2 fuel filters, one on each side of the pump, the factory line attaches to each filter and the other end of the filter has 5/16 line slid over the filter , the inlet to the msd pump is 3/8 so used fittings to make a 3/8-5/16 adaptor. power is through the underhood fuse/relay box, pulled the stock fuel pump relay and figured out which spot was hot with key on but off with key out, put a spade lead in there with a 25 amp fuse on it. pump is a little noisy (heck, its meant for when you swap in a efi engine into a non-efi chassis) but it works. gas guage still works, it must get its power source seperatly. was about 130 for the pump, filters 9 a piece, im guessing another 20 or so for the hoses, clamps and wiring. yes a stock pump might have been a little cheaper but it sure was easier and quicker to do it this way.