94 Ranger cranks but won't start

[explorerhavok]

I normally have an affliction for Explorers, I have had four in the last couple years, but decided to swap over to a Ranger as there is more that can be done with them. I bought a 94 Ranger XL with the 4.0 and a manual trans in it, bought it cheap since it won't start. My plan is to get it running and then swap in a rebuilt 4.0 I already have. So here is my dilema the engine cranks but won't fire, guy I bought it from replaced the battery and the starter, which didn't fix it. I noticed when I turn the key I can't hear the fuel pump running so I figure that is a possibility and I will test it when I get the truck somewhere I can work on it. Thing about the fuel pump is the guy I got it from said he ran a wire from the battery to the pump and it worked but still wouldn't start. So I am not sure if it is the pump or something else, possibly electrical. Also something else I noticed is that the check engine light doesn't come on at all when I turn the hey, I know in my explorer it comes on when I start the engine. Could this be the sign of another problem? Also I did some quick testing and I know I have power as far as the connector for the ignition coil pack. Any advice on possible problems or awhat to look for would be appreciated.

 

[OldJunk]

Check the fuel pump shut off ( inertia) switch, may have been tripped.

 

[explorerhavok]

Checked the inertia switch, button is down. Is it possible the inertia switch is bad? One thing I had forgot, truck was running and just quit one day.

 

[OldJunk]

Check associated relays,fuse.but it sounds like pump in tank is D.O.A

 

[rags]

Had the same problem, if the truck has a/c switch the a/c relay with the EEC relay and see if the check engine light works at Key on Engine off. If that relay isnt working your computer has no power & you will have no fuel pump & Spark.

These relays are in the engine compartment next to the battery > The Fuel pump relay, EEC relay & A/C relay are all the same. Just make sure you switch the A/C & EEC. If no A/C I would just go buy a new 1 they are not expensive

 

[explorerhavok]

Went at lunch and tried the swap for the EEC Relay, still no check engine light, no fuel pump noise, no spark. Begining to think the PCM is toast, what else can it be?

 

[parkrangerjeremy]

Yep it is most likely your computer had the same problem in my 93 and after a week of messing around with it i found out i had no check engine light, injectors werent noiding and the fuel pump wouldnt turn on. I put a new computer in it and it fired right up. hope this helps

 

[poorboy]

id put i fuel pump in it... if no start then id check the injector pulses if they are good then check the crank sensor

 

[explorerhavok]

Pulled the computer and opened it up, got some burnt components so I am pretty sure that is the issue. Sending it out to be repaired. I'll update if it works or not.

 

[poorboy]

thats never good... itll buff out tho

 

[mlunsford]

yu can check the fuel pressure valve on the intake, easy.
My 94 has had bad relays for fuel pump, bad grounds (would just stop), and replaced the starter, and rad. But not bad for 212K miles

 

[explorerhavok]

Still in need of help badly. Still cranks and won't start- still no spark, no fuel pump noise, no check engine light. Not sure at this point if no check engine light is relevant. Here is what has been done: battery and starter replaced by previous owner. Checked electrical to ignition coil pack with good results. Checked fuel pump relay and eec relay by swapping them with the ones in my running explorer, explorer still runs. Pulled power train control module and had it rebuilt because it had some burned parts inside. Checked underhood fuses for ignition, fuel pump, etc.- all good. Any help would be appreciated. JUST NOTICED THIS: HEGO HEATER FUSE BLOWN, would this cause my problem? Craft shop closing and got to go buy fuse to try tomorrow, any input

 

[Stranger ranger]

Check all grounds. Ignition switch could be f'ed. I would swap in another computer just incase. maybe one from a junkyard or your explorer if its from the same year. Might as well give it a shot aint it?

 

[Earl43P]

No, the HEGO fuse only feeds the two upsteam O2's and will not cause your problem.

Here's the deal:

Check/replace the PCM Power Diode.
It routes power through the PCM Power relay coil. If that relay coil doesn't get power, neither does the PCM, hence NO CEL with key to Run.

You should also verify the EEC Pwer fuse is good (the only 30A, under the hood).

PM me your e-mail address and I will send you 93 schematics. Should be the same.

Just re-read all your symptoms: The EEC Pwr and FP fuses both get their "Hot at all times" power from the same source. You should check each of those fuse holder sockets for power and work back from there, if power not present.

The fact that the PCM is not getting power (no CEL) means the PCM cannot provide the ground to the FP relay, so the FP can't run.

With the PCM Power Diode still installed, probe its sockets for 12V (with key in Run). Both sides should have 12V. EDIT: If Diode has no power, go after the ignition switch: power to diode comes straight from Ignition switch, in Run. (thanks, Stranger)

This could also be a bad ground #101. Follow small lead from Bat - straight to the radiator support. Clean/verify that ground.

 

[94EXPLODER]

had that same exact problem this past summer....all same signs and symptoms....torn everything apart all electrical all fuel....ended up being the PCM relay $13.....