Electronic control module

[Mary lou Wood]

Engine turns over but wont crank. Thinking it could be the ECM . Any thoughts ? Btw where is the ECM located on my 94 explorer ?

 

[Brian1]

Passenger side front floor area under the plastic trim "kick" panel. Loosen a screw or 2 on the threshold trim and remove the bottom screw on the a-pillar trim piece about mid-dashboard level then the panel will pop out, it is held in by a single plastic push pin and tucks under the door threshold trim piece.

I doubt it is the ECM though, check the sensor wires to be sure they aren't loose, check for fuel pressure and pull the codes.

 

[natenkiki2004]

Well before you throw a PCM/ECM at it, check things first. You say it turns over but doesn't crank? Those are the same thing. Does the CHECK ENGINE light come on when you turn the key to the "on" position? If not then your PCM/ECM isn't getting power, check the relays and fuses. If the light comes on then check for spark. If you have spark then the engine is seeing the crank signal and processing it, at that point you're missing fuel. If you don't have spark then you need to find out why, whether it's a faulty coil pack, bad ICM, bad crank signal, bad wiring, etc... If you have spark but not fuel, go after the fuel pump (you should hear it whine for 2 seconds when you turn the key on "on").

 

[malohnes]

Lots of simple things to check before going hardcore, like Nate and Brian stated. What happened since the last time it started and the recent time it wouldn't start? You might find clues there... Blown fuses, loose connections, corrosion in battery cables all can prevent starting.

 

[trashtruck]

agree with the above, the electrical system is the weakest link in any vehicle. check for spark and power to the fuel pump. check inertia switch and relays/fuses.

 

[FixingDaily]

Well before you throw a PCM/ECM at it, check things first. You say it turns over but doesn't crank? Those are the same thing. Does the CHECK ENGINE light come on when you turn the key to the "on" position? If not then your PCM/ECM isn't getting power, check the relays and fuses. If the light comes on then check for spark. If you have spark then the engine is seeing the crank signal and processing it, at that point you're missing fuel. If you don't have spark then you need to find out why, whether it's a faulty coil pack, bad ICM, bad crank signal, bad wiring, etc... If you have spark but not fuel, go after the fuel pump (you should hear it whine for 2 seconds when you turn the key on "on").

If you don't hear the fuel pump when tuning the key to run position, I would check the relay box first. My 94 (owned since new) had two relays in the fuel pump path that were intermittently failing (These being the PCM Power Relay and the Fuel Pump Relay). I found the relay positions affected by looking at the Haynes manual and the vehicle owners manual. I found that by jiggling the particular relays, I was able to make the fuel pump come on. I cleaned the contacts in the box and replaced the relays (and they were fairly inexpensive to replace). No problems with the relays since. The fuel pump did need to be replaced once in the 22 years we have owned the Explorer, so that could still be an issue, but check the relays first.

 

[92exp4x4]

agree with the above, the electrical system is the weakest link in any vehicle.

I think it's the nut behind the wheel in most cases!