Weekend cut short......Ignition module dead - Off-Road Forums & Discussion Groups
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post #1 of (permalink) Old 09-01-2000, 07:00 PM Thread Starter
I Might Just Know What I'm Talking About
 
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Weekend cut short......Ignition module dead

My weekend has been cut short. I was all loaded up and rolling, as soon as I hit the highway, the jeep sputtered and came to a halt. The ignition module has apparently stopped getting power. I have a wiring diagram, but relating it to my jeep hasn't help me locate the problem.
I replaced the module, and coil. Nothing has changed.

I read my Haynes manual, but the only test it has involves an ohm meter. Is there a simple test I can do? I realize the module is supposed to be getting two power supplies but what wires? I have a red one that is constant (and working), but what is the other one? I'm heading to the junkyard in the morning to buy another distributor. But if I can get some advice, maybe this won't be neccessary.

Anyone have any comments?

btw.... Thanks Ricky (z50k2)..... he stopped and loaned me his spare module. I just wish it solved my problem. But he is a true Jeeper.

<font color=red>IN2DEEP 78 CJ5</font color=red> <font color=blue>302 FORD </font color=blue> [img]/wwwthreads_images/icons/shocked.gif[/img] <font color=red> T176/D300 REAR ARB 35" BFGS </font color=red>
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post #2 of (permalink) Old 09-01-2000, 10:04 PM
 
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Re: Weekend cut short......Ignition module dead

I'm assuming you have the DuraSpark module on the fender.
If this is correct Tap three times....

Distributor is almost NEVER the problem....

Attached is a test wiring diagram.
If this doesn't get you running, it may be the distributor, but this is about a half an hour, and $0.50 worth of wire and male and female spade connectors.

Let me know if this is the problem, and then we'll go after a permanent wiring harness...

"I Have The Body Of A God... Buddha"
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post #3 of (permalink) Old 09-02-2000, 12:32 AM
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Re: Weekend cut short......Ignition module dead

I had the same problem. I started my Jeep to check out the rough idle. I couldn't duplicate the problem unless it was warm. Finally after a couple of hours I duplicated the problem. Turned off the Jeep and wouldn't start. Would crank but not fire. I checked everything having to do with the ignition. The biggest clue was I wouldn't get a spark. Turned out to be the Computer, I also tried to replace the Ignition Mod., and didn't make a difference. Try testing all of your ignition components, if still doesn't start, and doesn't spark, check out the ECM.

About $120

J just
E mpty
E very
P ocket!!

'85 or is it a '98?? Cj-7 33x12x15" BFG 2.5" Rancho 258 T-176 Almost EVERYthing Rebuilt or Replaced
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post #4 of (permalink) Old 09-02-2000, 08:18 AM Thread Starter
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Re: Weekend cut short......Ignition module dead

Thanks TR. I do have the duraspark ignition. Factory Jeep-Ford set-up. I will run the test wire set-up.

Am I reading this right? The red and white wire get 12V? For some reason I was thinking that I had a lower voltage power source. My red wire is HOT already. So the problem must be with the white wire. If I remember correctly, the red wire was the only one that had power.

I didn't think it was the distributor either, but it was a check I could run, just to eliminate another component.

Also. just for informational purposes. The diagram you drew came in real foggy. I'm thinking it's my computer, but I can't seem to find the right button to push, to straighten it out.

Jon, my CJ5 is evidently a little older than yours. Niether my Jeep or me have a brain (ECM).

Thanks again.
Drew

<font color=red>IN2DEEP 78 CJ5</font color=red> <font color=blue>302 FORD </font color=blue> [img]/wwwthreads_images/icons/shocked.gif[/img] <font color=red> T176/D300 REAR ARB 35" BFGS </font color=red>
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post #5 of (permalink) Old 09-02-2000, 11:11 AM
 
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Re: Weekend cut short......Ignition module dead

Red and white wires should NOT have power before you turn the key...

Depending on how it's wired, it should get power to one or the other during cranking and during run conditions.

If you can't read the graphic, give your email and I'll send the info there...

"I Have The Body Of A God... Buddha"
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post #6 of (permalink) Old 09-02-2000, 12:25 PM Thread Starter
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Re: Weekend cut short......Ignition module dead

TR.

If my red wire is hot with the key in the "on" position, can I assume that the white wire should be hot when in the "start" position? I was wanting to remove the wire from the starter solenoid, then hold the key in the "start" position. Then I should be able to use my test light to see if I'm getting any power. I put power to my two pronged connector (red wire and white wire) and my coil (all at one time). I was hoping just to get the thing to react to anything. But still nothing.

My emailt address is [email protected]

UPDATE: I did just this: I have power to the red wire with the key in the "on" position. I removed the wire from the solenoid, and I have power to the white wire, in the "start" position. So far so good. I also wired an extra distributor into my harness. I rotated the distributor, but I didn't get any response.

So now what??

Thanks,
Drew

<font color=red>IN2DEEP 78 CJ5</font color=red> <font color=blue>302 FORD </font color=blue> [img]/wwwthreads_images/icons/shocked.gif[/img] <font color=red> T176/D300 REAR ARB 35" BFGS </font color=red>
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post #7 of (permalink) Old 09-02-2000, 02:17 PM Thread Starter
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Re: UPDATE II

OK..... went back to Advance Auto.

results of testing:
Original Module: Pass
Module bought to replace original: Fail
New module to replace bought replacement: Pass

So now I've gone home, installed newest module. NOTHING. My coil is getting power to the positive side, but nothing out the negative side. I have been told that I should be able to get a "pulse" on my test light on the negative side of the coil while the engine is cranked. This means that my distributor is NOT working. Since I'm getting no "pulse" = replace distributor? I guess I'm going to wire the "new" distributor into the harness and see if I can get a pulse.

Drew

<font color=red>IN2DEEP 78 CJ5</font color=red> <font color=blue>302 FORD </font color=blue> [img]/wwwthreads_images/icons/shocked.gif[/img] <font color=red> T176/D300 REAR ARB 35" BFGS </font color=red>
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post #8 of (permalink) Old 09-02-2000, 09:45 PM
 
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Re: UPDATE II

Here is a partial list if things I would check...

1. The Ignition coil. Look for about 0.80 Ohm to 1.35 Ohm resistance across the primary windings. (Low voltage side)
0.45 Ohms if you are using the E-core (TFI Style) coil.

2. Check the engine ground. The entire ignition system trys to ground through the distributor housing, via the black wire from the module to the distributor.
That black wire is the ONLY ground for the entire primary side of ignition.
You can splice the black wire out of the module directly to ground.
I didn't say cut the black wire, I said splice into it, and wire it directly to your master ground, or the negative side of the battery.
Those aluminum distributor housings loose ground all the time, but that's not what it sounds like here.

3. I'd check the green wire from the module that goes to the negative side of the coil.
Lots of times that wire will corrode in the two or three connectors it has to go through, and won't allow the coil to trigger.
(This is real common)

4. I'd run a test harness, like the one I posted earlier, to rule out the factory wiring harness.
Use 1/4" male and female spade connectors, preferably insulated, to make the test harness.

You build the test harness and you have the potential to bench test all of your components.
Use a GROUNDED test plug in the ignition coil, and wire you module and coil up to the 'extra' distributor, and attach the entire mess up to a battery.
Wire it up just like the drawing.

Spin the distributor, the test plug should fire. If it doesn't, you have a bad component.
It wouldn't be the first time a coil or module was bad and the local Auto-Jerks couldn't diagnose it....

P.S., using the second distributor on your stock system almost eliminated the distributor as the cause already.

5. If you have a factory tach, I'd check on that circuit. I don't think factory tachs were offered until '80 or so, but I'm not sure, and the way the factory harness is run, if the tach fries, the ignition won't work either about half the time.
CJ8/5.2Mag is the sharpie on the factory tachs on this board.

6. Make a test plug by taking a old spark plug, and wrapping a copper wire around it tightly, and grounding it to a KNOWN good ground.
Never fire an electronic ignition with out a test plug.

Hook the test plug up to the ignition coil, ground the negative side of the coil (green wire), and apply positive power to the positive side of the coil. Just strike the positive wire to the terminal on and off real fast...
the plug should fire on some of the tries when the circuit breaks (power goes off).

7. Hook every thing up as stock, except for the power wires to the module.
Supply power for the module from the battery via an assembled jumper wire.
Spin you distributor and see if the test plug fires attached to the coil.
That will test you power circuit. I don't think that is what it is from what you have already done, but leave no stone unturned.

With a test harness you can limp home even if the entire wiring harness fries.
Most of the time it's bad connections....

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post #9 of (permalink) Old 09-03-2000, 03:40 PM Thread Starter
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Re: UPDATE II

Ok......evidently my coil went bad. I replaced it once on the side of the road, but I had the new "bad" module installed at that time so, no good. This morning I went out to test my coil. I tried to get a spark with the spark plug and hot wires as TR discribed. But evidently I didn't do something right. I couldn't get a spark out of either coil (new or old). Out of frustration, I just hooked the new coil in place, and hit the key. The engine fired right up!! I'm back on the road again. Just two days late.......

Thanks TR, for all of your help and information. I know how frustrating this is in person. It has to be twice as bad trying to diagnos long distance.

Thanks again.
Drew

<font color=red>IN2DEEP 78 CJ5</font color=red> <font color=blue>302 FORD </font color=blue> [img]/wwwthreads_images/icons/shocked.gif[/img] <font color=red> T176/D300 REAR ARB 35" BFGS </font color=red>
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post #10 of (permalink) Old 09-04-2000, 08:11 PM
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Re: UPDATE II

Drew, glad you are back running. Wish you could have made the trip. Give me a call this week and I'll tell you how I ate a ring and pinion gear and a left axle u-joint all at one time...Ricky...seeya...

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