'94 Explorer cranks but won't start?

Question

'94 4.0L OHV
The bewildering part is that it has fuel pressure at the rail (checked with gauge), it has spark, and it has compression. It cranks strong but does not even think of firing -- no sputtering or anything.

Because the spark plugs are not wet and because I cannot hear the injectors click with my stethoscope, I do not believe that the injectors are firing.

I have replaced the Crank Position Sensor and the computer (PCM) and have gotten the same results. I have checked all of the grounds to the PCM as well as the 12V leads and they all check out. The leads to the CPS are also good. The injectors are getting 12V+ on one lead but I am not sure if they are getting the negative pulse from the PCM (although I know the wire is good).

Also strange is that the PCM will not allow me to read the EEC-IV codes although all of the wires to the test connector test out alright.

I'm about out of ideas here -- you guys have any thoughts?

1.) the gas in there is good - I'm sure of that...
2.) the camshaft has to be lined up at least well enough because it's got good compression
3.) I can't check the static timing because it's a coil-based ignition system, no distributor... I tried to check with my timing light, but because it was just cranking, it was too slow to be able to tell anything
4.) I'm sure that the plug wires are good because it's getting spark.

The PCM won't spit out codes and the injectors aren't clicking... it has to mean something. I've heard that someone else had the issue, but I never saw the resolution...

Answer 1

All Ford vehicles have a "fuel inertia switch" aka "fuel pump cut-off switch"
Is it possible that the switch has been triggered ? Usually triggered by moderate to severe rear-end impact.

check to see if fuel pump is not working due to this.
locate reset button.

(I'm trying to remember where the switch or 'button' is located on the '94.....)

Do you have an owners manual? if so turn to the chapter on "Roadside Emergencies" the section about the fuel pump cut-off switch within the first few pages of that chapter & it will show you a diagram of where the switch or button is.

If you don't have an owners manual:
it's usually located in one of three places on most Fords:
look in the rear cargo space, on the passenger side interior wall.
look by the 'kick panel' where the drivers left foot would rest
look by the 'kick panel' where the front passengers right foot would rest.

you are looking for a small (about 2" tall) module.The top part of the module is a little red button. If the button is popped up, just depress it to reset the fuel pump.

(Sorry for the 'laymans' terminology , I sell Fords, I'm not a mechanic)

I Hope I've Helped

Answer 2

Ok, try this, Replace or swap the PCM relay. if this doesn't work check all the fuse links at the starter relay on the fender. Also has anything been done to this truck lately, Like a wreck, body work,any maintenance, tranny work, etc, If so look in the area that has been worked on for any damaged wires or grounds that may have been left off or loose. Try loosening the ground wire bolts and re tighten them. The injectors do have power and the pcm grounds them. Apply ground to the injectors WHILE cranking the motor and see if it will if it trys to start. This will not hurt the PCM. From what I have read of what you have done, I would do this. One more thing I would do, unplug each sensor one by one and see if it starts, Map,Ect,Baro,O2s,Dpfe,etc. I have seen a sensor have a eternal short and cause the PCM not to have codes and shut the system down. Something else, there is a 50 pin connector at the main harness from the motor, unbolt it and check to see if any pins are bent and not pushed back. I think there is a ground wire on the back of the motor, it may be orange colored, be sure it is not off.

Answer 3

Is there any way to check the static timing? Can you take a cover off the front of the engine to see if the crankshaft and camshaft line up at the correct timing points? There may be a cam sensor that you can check, as well.

You might also have gotten a bad tank of gasoline. And have you checked the actual spark plug wires or just the wire from the coil to the distributor? Be sure the plug wires are good.

It sounds like a bummer, though. I've been there and appreciate what you're going through.

Answer 4

94 Explorer

Answer 5

Ignition Module.
It's located under the coil packs.

Answer 6

replace fuel pump relay or maybe it has something to do with the security system or sometimes there is a reset button that stops the car from starting if someone hits you

Answer 7

does it have gas? you have tried everything else try some gas.
run injector cleaner won't hurt. change spark plugs. hope i helped

Answer 8

Try unplugging the crankshaft sensor, then plug it back

Answer 9

junk it...