'92 Eddie Bauer cranks, but doesn't start (tried TONS of things)

[gemini child]

Bought the truck, drove it home, shut it off infront of the garage. And that's where she lays.
It is definately NOT a starter or fuel related issue (checked both extensively.) The spark is very very weak. (it just cranks, no start)
Swapped ignition coil, crank sensor, and EEC (? not sure thats the right name for it. THe black box on the rad cradle, next to the passenger headlight with a 12 pin harness.) Changed to new plug wires and plugs, battery, battery posts, and various other positive wires. Remade grounds from battery to frame, frame to motor, motor to battery, and just to make sure I added a ground from the ignition coil bolt to my grounding point between the battery and motor. I measured 12.5 volts on the postive wire going to the ingintion coil and 1.5 ohms from the coil bolt to the battery post; so both are good.
Connected Snap-On scan tool, did a wiggle test and a crank test. Nothing significant showed. The scan tool gave me the diagram and measurements for the EEC and the measurements for all 12 pins. So far the only thing that I've found to be inaccurate is the negative ignition pin (pin 4 I believe); it's not showing a ground at all. (Used a DMM for all measurements). I also measured off to insure voltage was good at key cylinder, main harness, main fuse box, each fuse, relays below fuse box, and at the ignition coil. :fire:
Two days later, my conclusion is somehow, somewhere there must be a broken wire or bad conection in a plug. Likely between the EEC and the ignition coil, but no luck so far.
Does anyone know where or what my problem is, or have had this happen to them and could throw us a bone!?

 

[TPLYNCH]

Did you replace both the positive and negative battery cables. They tend to rot on the inside. Another possible item is the crankshaft position sensor.

Does it have the flashing THEFT light in the dash (PATS), or an aftermarket alarm? If the Ford PATS system, are you using the correct key with the microchip in it? If aftermarket alarm, is it disconnected?

 

[gemini child]

Thanks for the response.
I didn't replace the postive cable because the voltage at all points measures up ok..however tomorrow morning I'm going to change ALL main power and ground wires under the hood that I haven't done already. I already swapped the crank sensor, didn't help. The vehicle doesn't have PATS so that's not the problem. Also doesn't have any aftermarket moduales.

Any other ideas/help?

 

[glfredrick]

Bad replacement module? I've had several...

Fuel shutoff inertia switch?

Timing chain jump on shut off?

Broken wire somewhere?

Fried computer? (have seen those too)

 

['92Bauer]

You said, you just bought the X, did you go to the previous owner and ask them what the problem might be? Sounds dumb but yon never know.

 

[rogerthatone]

I believe those have a cam position sensor (which as I recall is fairly pricey). It sounds to me that could be the problem. I'll try to post more information on this tomorrow after work when I have more time.

 

['92Bauer]

Not to sure but I do not believe first gens or at least 91-92 have cam position sensors, I believe they have crankshaft postion sensors.

 

[elkhunter]

The battery cables could be good enough to carry the existing battery voltage but what cable is left inside the jacket could be corroded to the point that it cannot carry the amperage to the starter. A small wire under these conditions would start smoking but the heavy jacket on a battery would conceal the smoke for quite awhile.

 

[MrShorty]

You say it's a no start, and that it has weak spark. Any codes in the computer, or does it pass all tests? BTW, that box you replaced next to the headlight is the ICM (ignition control module). The actual EEC module is behind the passenger kick panel below the glove box.

Sometimes, places like Autozone can test the ICM for you.

Did you figure out what was going on with pin 4? My wiring diagram shows that pin 4 of the ICM is connected to pin 16 of the EEC module (Think it's 16, my diagram was a little hard to read).

 

[gemini child]

Thanks alot for all the great responses; all were good ideas/possibilities. Hownever, I did get it running (FINALLY). I got pissed off and started from scratch. I rewired everything from the battery that I hadn't done already. Sadly, but luckily, I burnt my starter out in the process (the one I rebuilt one day before it stopped running.) So I put in another new starter. THe only difference was the one I rebuilt I did with a rebuild kit from Canadian Tire (bad idea...) The new one I put in I had my friends at a local business rebuild for me. I also bought a new/better spark gauge from Snap On that was adjustable, and my spark tested good. The first time I turned it over, the X started.
So in conclusion; the problem was in a poor quality spark tester (very misleading), and the killer blow was the rebuild kit that I got from Canadian Tire had an underdrive starter gear, therefore the truck wasn't turning over fast enough to start. On the upside, the whole truck is now rewired and I got rid of alot of corosion of bad wires (which could of been aiding the problem).
And I came across another peice of interesting info, for anyone out there; do not trust the diagram for firing sequince on a 4.0 L sohc in the Hanes manual. It's 180 degrees reversed. The correct timing however is provided in this forum!
Once again, thank you for your time! (and to the creators, a thank you for providing an ACCURATE and free source of information...the timing info saved my motor).

 

[TPLYNCH]

Glad to hear you got it straightened out! Just to be clear - you have the OHV engine, not SOHC. The SOHC is in '97+ Explorers. What year Hanes manual were you looking at?