Need Quick Help... SOLVED.. Thank You

[tedw49]

1994 explored stock 190,000 miles 4x4 auto 4.0 liter

Just sold it and they drove it 2 miles and it just quit running.. turns over good.. at one point i trying to get it to run it did start but as we started feeling good about it, it shut down again

where is fuel filter and do i need special tools and is it a pressurized system

please also tell me about the ignition system.. what can i check... Not a claimed mechanic but i do all my own repairs .. just need guided along.
Thank you..

 

[ChildIdenticant]

fuel filter is driver side, right behind the wheel, on the inside of frame. If you are trying to check fuel delivery borrow a fuel pump test kit from local parts store. There is a valve in your fuel rail to connect it, next to fuel pressure regulator. It will be near the top center of the engine, looks like a bicycle tire valve. This valve is also the way to depressurize the line. Tell the new owner this site is their friend

edit: I tried to give you the information for which you asked, making no assumptions of the information you may actually need. And yes, a special fuel line disconnect tool is required. It is a cheap nylon ring. There is a trick to removal, also available via this forum.

 

[tedw49]

Thanks..found and changed the filter.... while the supply side was still disconnected from filter i hooked back up inertia switch ..made sure it was reset.. and turn on the ignition.... no fuel.. checked fuel pump relay and 20 amp fuse and they are good.. cannot find a connector for the in tank fuel pump so it must be on top of the tank.. looks like i get the fun of dropping the tank..Just to test for power.. I have a Haynes and Chilton manual for this rig.. both good for wiping... on this problem but nothing else.

 

[Turdle]

Fuel pump power only shows for the first 1-2 seconds after turning the key to run. You might have a helper turn the key for you. The fuel pump will run continuously only once the engine starts.

You might triple check the fuel pump relay socket for bad connection. wiggle test with key on.

does check engine light turn on with key on?

 

[tedw49]

I will do a lot more checking tomorrow.. But I know fuel pump is not working whether from lack of power or fried because with fuel line disconnected from the fuel filter it should pump fuel with key on.. it does not.

 

[tedw49]

problem right now is to verify whether pump has power I have to pull the tank.. If i had a electrical schematic I MIGHT be able to find the right wires before the tank but seems nobody.. (Chilton or Haynes) believes in providing this important piece of information..

 

[Turdle]

Yes, but i was going to the other end of the circuit first. If the ECM has no power neither will the fuel pump. Do you have fuel pump power at the inertia switch for a few seconds after key on?

 

[tedw49]

will be checking that tomorrow.. had to stop working on it to get it wreckered home.. setting where it was would have resulted in broken windows and loose of tires.. LOL

But FYI.. I am betting on bad ECM or PCM.. in which case it will result in another wrecker ride to the local dump.. It has been running great.. and then to just stop.. no hesitation or burps and jumps.. a total run power outage usually never turns out good..

 

[Turdle]

ECM failure is rare. If it is not a self induced ( new owner-passenger kicked inertia switch and tripped it or broke wires) or a coincidental relay-wiring issue, I would suspect the fuel pump.

Check the middle of the circuit first-which is the inertia switch. If you have no 1-2 second pulse of power there, work your way back to the power box and ECM relays
if you do have power at the inertia switch, check it's wiring real good for broken wires, then look into the fuel pump connector for power.

 

[Turdle]

Is the truck parked on level ground with over 1/4 tank of fuel?
A sacrificial dial type air gauge can be used in a pinch to check for fuel pressure on the fuel rail shrader valve. Look for a black plastic tire valve type cap. ( just to make sure this is a fuel delivery issue.)Turn the key on and off 3 times, leave it turned on and jam the tire gauge down onto the valve. You'll squirt some fuel when it is released, so beware of that.

 

[tedw49]

Ok.. i am following you but why would it not put fuel out of the line when i disconnected it from the filter??.. i turned the switch on and off several times.. (not start) and got no fuel.. and yes it is on level ground and half a tank of gas.

As far as the Fuel pump connector it must be on top of the tank.. My books show 'later models' (what ever that is) as having the connector on the inside left frame.. There is none there... One book says the wire to the pump is dark green and yellow.. while the other book says pink and black.. so when i get into the frame harness. IF need be.. i have to hope both colors are not there..

 

[tedw49]

Ok.... inertia switch is good (continuity) no power to inertia switch(approx 2 secs.. run.. off.. run.. off etc)...... fuel pump 20 amp fuse good.. relays good ( new).. But a clue ..maybe.. with fuel pump Relay removed.Key off.. I have power to one connector as I should.. with key ON.. I have power to all 4 relay connectors Test with Light and DMM. grounded to Battery Negative..same with the ECC relay .. Heater relay reads as normal..one key off hot.. and one more with key on..

seems a short somewhere..

Whatcha think..

 

[tedw49]

Ok .. for some clarity.. i have two engine wiring diagrams both that i have to use a magnifying glass to read.. one is a 94 and one is a 95 explorer.. the 95 is closer to what i am finding but I am using both.. both show a PCM relay.. but my actual vehicle does not show a PCM relay.. It does show a EEC relay.. I have now just discovered they are one and the same so I will refer to them as PCM going forward

 

[Turdle]

Ok yes, the issue is under the hood. Unless the fuel pump itself is shorted. Try the relay lug power probe check again, but this time unplug the wiring to the inertia switch to eliminate the pump from the circuit.

 

[roscoe 0202]

try new fuel pump relay and pcm [eec] relay pcm turns fuel pump relay on sounds like a fuel pump to me
roscoe

 

[tedw49]

I have new ones bought yesterday.... That should have m nothing to do with having power to all 4 connectors in the power outlet box with key on and relays removed. I also found my old circuit probe is going bad so am going to back up on the inertia power test with new probe..

 

[tedw49]

Ok.. I want to thank everybody for their input.. always grateful for it..
I think this is beyond what we can figure out on here and beyond me.. If i had to guess i would say the PCM is gone..

In pulling every Relay in the power distribution box and testing each Relay position socket I get a different outcome on each one and the only one that tests correct is the one for the blower which is also the only thing that is working as far as the relays go..

With relays removed in the Fuel pump relay circuit i get.. KEY OFF..Hooked to Battery negative.. one live connector ..as it should be.. Key On.. I get 3 live connectors where it should be 2.. Moving the tester to Battery + I should get one negative feed.. I do not get any...
PCM Relay.. Key Off I get one live feed as i should.. KEY ON ... I get 2 live feeds as I should.. but again no negative connection
ON A/C W/O Throttle.. key off I get one live feed as I should.. KEY ON... I get only the same one and no others.. and again no negative signal
Heater Blower.. Key Off.. I get one live connector.. Key On .. I get 2.. live connectors as I should.. Check for a negative connector and I have 1.. as I should have.. and rotate all relays new and old thru heater and all work..

I also have to apologize, as some of the previous information was done with a worn out L.E.D probe.. I bought a new incandescent probe and a lot of the findings changed .. Also I pulled the inertia switch to be sure of findings.. It does have continuity.. testing wires disconnected from the switch i get no voltage to the either wire with or with out relays plugged in and with or without the key on (not even 2 seconds worth).
Looking at the poor wiring diagrams I do not really see how the PCM can be the cause of this, However the only other thing I can come up with is a short with wires melted together and/or burnt off but I find no sign of that.. no visual or smell and no fuses have blown..

I will probably mess with it a bit more as i calm myself but it is not worth sending to a shop and I cannot afford that anyway so right now it looks like it will be on it's way to being a soup can..

 

[tedw49]

Fuel pump power only shows for the first 1-2 seconds after turning the key to run. You might have a helper turn the key for you. The fuel pump will run continuously only once the engine starts.

You might triple check the fuel pump relay socket for bad connection. wiggle test with key on.

does check engine light turn on with key on?

No there is not a check engine light..

 

[Turdle]

OK, the PCM is not getting power. which is why none of the 12 lines are switching low. Once they do, the fuel pump will run.
are you certain you used a known good 5 post relay in the PCM relay circuit?

The PCM is located behind a cover on he passenger side foot area near the inertia switch.

I have seen some posts concerning the PCM , leaking capacitors and such, but nothing like a dead PCM.

is this diagram close to what you see in your power distribution box


1994 ford explorer power distribution box - Google Search:

There should be a fuse protecting the PCM , also, there is a "ECM power diode" to check.

Ford called it a ECM for 1st gens, and changed it to PCM for obd2 for some reason but we all understand what is meant by calling it either.

 

[tedw49]

I have the kick panel off and can see the PCM... My relays all check good.. Plus i bought 4 new ones
The diagram is like my PDB.. Mine is with out the ABS relays and fuses and have been since i have known the rig.. about 7 years..
I will look for and check The diode.. All fuses in PDB have been checked and are good..