I have a 1994 4.0L Explorer that keeps blowing the EEC fuse. The problem was discovered after the engine died and hasn't started back since. I thought it was the fuel pump because it wasn't coming on when the key was turned on. After inspecting the pump, I discoved that the EEC fuse was burned out. Now everytime I turn the ignition to the "on" position, the fuse burns out. Is it just a short somewhere? Sensor? Thanks!

 

Did you find what was wrong with it yet?? I also have the same problem. Thanks!

 

The EEC fuse protects most of the EEC-IV system, including the computer module, the sensors, and the solenoids the EEC-IV computer controls. I wish I had a quick, easy answer, but I don't. As tedious as it is, I would suggest you get a wiring diagram and a voltmeter, and start tracing wires until you find the wire/component that is shorted to ground.

 

Here is a path for the 30 amp EEC fuse, it is split into 2 parts for troubleshootong purposes.
1. Fuse is wired directly to EEC pin 1 and EEC power relay normally open contact.
2. From other side of EEC relay contact, it feeds the following (not necessarily in this order):
EEC unit pins 37 & 57
Wide Open Throttle relay winding
All fuel injectors
Idle air bypass valve
EDIS module pin 8
Fuel pump relay winding
Mass air flow sensor
Canister purge soleniod
Automatic transmission shift solenoids (if automatic trans equipped)

If the fuse only blown when key is turned on, the fault is in wiring path from EEC relay as described in item 2 above. If it blows immediately when inserted, the EEC is bad or EEC power relay has a short.

This should help you narrow it down.
Dialtone

 

Thanks for your suggestion on the eec fuse problem. I have 1992 ranger I replaced the trans and just turning on the key blew the 30amp fuse. At first suspected starter but then unplugged shift harness that goes to torque lockout and shift solenoids truck starts, no blown fuse. So I'll be replacing a couple of solenoids.