fuel pump questions.
#1
fuel pump questions.
Pulled my fuel pump, tested it with 12v, thing turns on. Tested my relay that's fine as well. Im gonna test continuity in the lines once i get some day light tomorrow but if those are fine and im getting continuity in all the wires what else would stop my fuel pump from kicking on? i don't have a pressure gauge to test the fuel line but i dont think that could help since the pump itself isnt turning on. I'm at a loss and i could use your wisdom guys.
#2
RF Veteran
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Fuel pump power
Battery--------30amp fuse--------fuel pump relay------inertia switch------fuel pump---GROUND
30 amp fuse is in the engine compartment fuse box, FP fuse
inertia switch is in passenger foot area, under glove box, they move it around, but usually just above the top of the carpet, also could be at the top of the kick panel.
Small box with a wire on each side, Red reset button on the top.
Fuel pump needs a good Ground as well as 12volts.
Battery--------30amp fuse--------fuel pump relay------inertia switch------fuel pump---GROUND
30 amp fuse is in the engine compartment fuse box, FP fuse
inertia switch is in passenger foot area, under glove box, they move it around, but usually just above the top of the carpet, also could be at the top of the kick panel.
Small box with a wire on each side, Red reset button on the top.
Fuel pump needs a good Ground as well as 12volts.
#4
Checked all the above and i'm convinced a wire is broken somewhere in the fuse box where the relay is plugged in or somewhere in the harness. I think i'm just going to run a toggle switch from the (red/black) wire of the fuel pump up to the battery and then ground the pump to the battery as well. Anyone ever done that before or is this a no no ?
#5
RF Veteran
iTrader: (1)
No one "plans" on being in an accident, that's the "no-no" of hot wiring fuel pump power, pump stays on feeding a fire if there is one.
But doing it won't hurt the fuel pump.
The 12volt wire to the pump needs a 30amp fuse inline, and that would run directly to the fuel pump, or to the inertia switch, for some protection.
You would use the "toggle" switch for the fuel pump Ground, NOT the 12v, Ground is easier and less chance of a short, and you don't need it to the battery, any cab ground will work.
If you want to trouble shoot it more.
Pull out the Fuel Pump relay
Key off
There should be 5 slots in relay plug, one should have 12volts, thats from the Fuel Pump Fuse.
Key on
A second slot should now have 12volts, thats from the EEC relay(next to fuel pump relay).
But doing it won't hurt the fuel pump.
The 12volt wire to the pump needs a 30amp fuse inline, and that would run directly to the fuel pump, or to the inertia switch, for some protection.
You would use the "toggle" switch for the fuel pump Ground, NOT the 12v, Ground is easier and less chance of a short, and you don't need it to the battery, any cab ground will work.
If you want to trouble shoot it more.
Pull out the Fuel Pump relay
Key off
There should be 5 slots in relay plug, one should have 12volts, thats from the Fuel Pump Fuse.
Key on
A second slot should now have 12volts, thats from the EEC relay(next to fuel pump relay).
#6
Well if i'm still awake after the accident ill try to turn it off haha. I really don't want to have to drop that damn tank again, and google isn't giving me the exact answer i want. Which one of the blacks is the ground to the fuel pump? im tempted to just cut them both and run them both to ground but if i can get the right one without having to possibly break my fuel gauge that would be great.
#7
RF Veteran
iTrader: (1)
Have a look here: http://www.justanswer.com/ford/3huzq...zda-b2300.html
Ground for Fuel Gauge sender in the tank shows Black with yellow or white stripe
Ground for Fuel Gauge sender in the tank shows Black with yellow or white stripe
#8
Have a look here: http://www.justanswer.com/ford/3huzq...zda-b2300.html
Ground for Fuel Gauge sender in the tank shows Black with yellow or white stripe
Ground for Fuel Gauge sender in the tank shows Black with yellow or white stripe
#9
RF Veteran
iTrader: (1)
Well, spark is working, or manually adding fuel wouldn't get engine to fire
So must be fuel injectors.
Each fuel injector should have 12volts when key is on.
Computer Grounds an injector to open it.
So there are 6 Ground wires from computer, but if even a few were broken engine would fire because the others would be opening.
I would bite the bullet and rent a fuel pressure gauge and a Noid Light
You really need a Noid Light to see if computer is Grounding an injector.
And pump running doesn't mean 35psi fuel pressure
So must be fuel injectors.
Each fuel injector should have 12volts when key is on.
Computer Grounds an injector to open it.
So there are 6 Ground wires from computer, but if even a few were broken engine would fire because the others would be opening.
I would bite the bullet and rent a fuel pressure gauge and a Noid Light
You really need a Noid Light to see if computer is Grounding an injector.
And pump running doesn't mean 35psi fuel pressure
Last edited by RonD; 03-09-2015 at 08:51 PM.
#11
if I am not mistaken, doesn't the fuel pump get a message from the electronic engine control?on my 94, the EEC relay and the fuel pump relay are exactly the same.when I replaced both of those relays, everything was fine.they only cost about 5 or 6 dollars each. and on another note, why are you dropping the fuel tank? Isn't it easier to remove the bed?
#12
RF Veteran
iTrader: (1)
if I am not mistaken, doesn't the fuel pump get a message from the electronic engine control?on my 94, the EEC relay and the fuel pump relay are exactly the same.when I replaced both of those relays, everything was fine.they only cost about 5 or 6 dollars each. and on another note, why are you dropping the fuel tank? Isn't it easier to remove the bed?
EEC relay closes when key is turned on
EEC relay gives power to the EEC(computer) of course, and also fuel injectors, fuel pump relay, and spark system on some models.
EEC(computer) does control fuel pump relay via it's Ground wire
EEC relay gives fuel pump relay power but since it isn't Grounded it doesn't close so fuel pump isn't on.
Computer does ground fuel pump relay for two second to prime system when computer first starts, it won't ground it again until engine RPMs are above 500, then computer grounds it until key is off or RPMs drop below 500.
In this case however poster does have a running fuel pump so relays should be fine, what is missing is fuel being fed into the intake, so fuel injector issue, assuming fuel is making it from running pump to the injectors, which is what a pressure test would show.
#13
I've frankenstein'd my truck pretty hard. I 5 speed swapped after my automatic trans died and from then on it's been a headache (no speedo, my key ignition has gone out on me so i jump the solenoid for the starter with a push button, and now this fuel problem) but i love this damn ranger to much to get rid of it.
I've got a friend thats going to let me borrow his fuel pressure kit but he hasnt gotten around to bringing it over. I'm currently throwing parts at it right now to try to fix it in the mean time. I put a new fuel filter in and i'm about to put a new fuel pump regulator on it but my haynes manual doesn't even list that i have one. Is the 96 a returnless fuel system or is there one located in there somewhere?
I've got a friend thats going to let me borrow his fuel pressure kit but he hasnt gotten around to bringing it over. I'm currently throwing parts at it right now to try to fix it in the mean time. I put a new fuel filter in and i'm about to put a new fuel pump regulator on it but my haynes manual doesn't even list that i have one. Is the 96 a returnless fuel system or is there one located in there somewhere?
#14
Well, spark is working, or manually adding fuel wouldn't get engine to fire
So must be fuel injectors.
Each fuel injector should have 12volts when key is on.
Computer Grounds an injector to open it.
So there are 6 Ground wires from computer, but if even a few were broken engine would fire because the others would be opening.
I would bite the bullet and rent a fuel pressure gauge and a Noid Light
You really need a Noid Light to see if computer is Grounding an injector.
And pump running doesn't mean 35psi fuel pressure
So must be fuel injectors.
Each fuel injector should have 12volts when key is on.
Computer Grounds an injector to open it.
So there are 6 Ground wires from computer, but if even a few were broken engine would fire because the others would be opening.
I would bite the bullet and rent a fuel pressure gauge and a Noid Light
You really need a Noid Light to see if computer is Grounding an injector.
And pump running doesn't mean 35psi fuel pressure
#15
RF Veteran
iTrader: (1)
Turning the key on and off does.
Remove the fuel filter in the frame rail, put a bucket under the lines, then turn key on, fuel pump will come on for 2 seconds and there should be fuel in the bucket, if not then issue will be from there back to tank or the "sock" filter in the tank with fuel pump.
If you get fuel out from the pump, then blow thru filter, make sure gas comes out easily.
Then pull off the fuel line at the intake/rail, blow it out
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