She died.....quietly

[CJim7]

spinnoff of my "what did you do to your CJ" post......

I rarely have had to deal with electrical issues in the 20 some odd years I've had this jeep, so I'm going to ask a really elementary question.

How do I check for spark without electrocuting myself

The CJ just died, could be fuel, could be the ICM. I'm leaning towards the ICM as the propane delivery system is almost fool proof. That, and LG always says to start at the electrical

 

[Hedgehog]

You need to generate a spark. Pull a spark plug or use an old one or just stick a nail in the spark plug cap, plug the wire to the plug and lay it somewhere with a good ground. Turn the engine over, there should be a spark, easiest done at night.

Now for the sticky part. Just because you get a decent spark with a cold engine doesn't mean the ICM is good. A cold ICM is not the same as a HOT ICM.

 

[CJim7]

You need to generate a spark. Pull a spark plug or use an old one or just stick a nail in the spark plug cap, plug the wire to the plug and lay it somewhere with a good ground. Turn the engine over, there should be a spark, easiest done at night.

Now for the sticky part. Just because you get a decent spark with a cold engine doesn't mean the ICM is good. A cold ICM is not the same as a HOT ICM.

Thanks HH. If I can get it started, I'll run it until its hot and see what happens...unless there is someway to test the ICM

 

[Petescj]

Thanks HH. If I can get it started, I'll run it until its hot and see what happens...unless there is someway to test the ICM

A lot of times when that Motorcraft box goes the backside of it melts if that's the one your talking about. 3 bolts on the fender , flip it and see.

 

[Torxhead]

Jim, great if you can get it started. A visual test like Pete suggested is a good point along with putting your hand on that icm to feel if it is hot to the touch, which means it is shot. Another thing it could be is the pick up coil in the distributor which can be tested by putting an ohm meter to the violet and orange wires out of the distributor and it should be 400-800 ohms. The coil can be another culprit and test the outer terminals to 1.13 to 1.23 ohms. It seems the ignition gets worse as it warms up. Sounds like you are still running the Motorcraft ignition which the factory Jeep repair manual does cover, good luck.

 

[CJim7]

A lot of times when that Motorcraft box goes the backside of it melts if that's the one your talking about. 3 bolts on the fender , flip it and see.

That's a good place to start, thanks Pete

Jim, great if you can get it started. A visual test like Pete suggested is a good point along with putting your hand on that icm to feel if it is hot to the touch, which means it is shot. Another thing it could be is the pick up coil in the distributor which can be tested by putting an ohm meter to the violet and orange wires out of the distributor and it should be 400-800 ohms. The coil can be another culprit and test the outer terminals to 1.13 to 1.23 ohms. It seems the ignition gets worse as it warms up. Sounds like you are still running the Motorcraft ignition which the factory Jeep repair manual does cover, good luck.

It wasn't hot at all when I touched it....I was sure to check. One thing that may be a culprit is the plug itself. It got shattered at some point when I was working on it and now it's just 4 spades plugged into the other end of the connector. This was real recent, but it ran just fine until now.
I'll have to look into the pickup coil. Again, my electronic skills are lacking...but if the pickup coil is bad does that require swapping out the dizzy? or can I just replace the pickup coil.

I'm running a TFI ignition...from a Ford 460, essentially still Motorcraft.

 

[CJim7]

Well, a quick google search showed me what I need to know about the pickup coil....and a cool U-tube video on how to test it with the ohm meter.

If it doesn't start, I think I'll start by checking for spark and working my way back through the ignition system.

If there's anything else you guys can think of.......

 

[hagar]

The plug on the ignition switch under the steering column can sometimes get hot and melt the plug and/or the ignition switch due to a bad connection.
Just thinking out loud...something else to check.

 

[Torxhead]

The CJ does have its weak points in the electrical system. If you still have it, the plug on coil clip is another that can be a problem when they get old. It did make for a quicker assembly at the factory though.

 

[Lumpy Grits]

Can you still crank the engine?
LG

 

[IOPort51]

check the ground on the ECM.

 

[mtnwhlr]

as the propane delivery system is almost fool proof.

Is almost fool proof, so you are sure it is working?

 

[IOPort51]

I built something that was fool proof once, took about three weeks for someone to come up with a better fool.

 

[CJim7]

The CJ does have its weak points in the electrical system. If you still have it, the plug on coil clip is another that can be a problem when they get old. It did make for a quicker assembly at the factory though.

That plug was replaced with the TFI upgrade.

Can you still crank the engine?
LG

Yes. It cranks but nothing else.

Is almost fool proof, so you are sure it is working?

I'm still digging into that, but I can see fuel vapor entering the carb. The carb is nothing more than a jet and a throttle plate with these systems. It operates on pressure from the regulator which I checked and confirmed is working.

 

[CJim7]

I built something that was fool proof once, took about three weeks for someone to come up with a better fool.

lol....quote of the week

 

[Lumpy Grits]

Have you look'd inside the dizzy yet? Everything look 'rite'?
Do you have an inductive timing light? The TL will confirm spark, when cranking.
Do you have voltage go'n to the coil?
WHO'S coil are you using? Do you have a spare to try??
LG

 

[CJim7]

Have you look'd inside the dizzy yet? Everything look 'rite'?
Do you have an inductive timing light? The TL will confirm spark, when cranking.
Do you have voltage go'n to the coil?
WHO'S coil are you using? Do you have a spare to try??
LG

I haven't had a chance to look in the dizzy yet.....with work starting back up I haven't had much time to do anything with it. I will just have to keep this thread updated. Might be a good opportunity for a tech article on the ignition system.
This is a Ford coil, from a 460cid. It's running to the stock Motorcraft dizzy with a upgraded TFI cap and rotor. No spare at this point.

 

[Lumpy Grits]

OK-Look for a possible damage'd rotor etc inside the dizzy.
Does the coil use the 'horseshoe' connector? Those are a well known problem area for lost contact.
Let us know when you get some voltage readings and we can go from there.
Best of luck.
LG

 

[Hedgehog]

....... (no joke) ...... is it wet in there? Wipe out the cap, spray with WD-40, give her another try.

 

[CJim7]

....... (no joke) ...... is it wet in there? Wipe out the cap, spray with WD-40, give her another try.

I don't know why it would be....but I will definitely check for moisture when I open up the dizzy. It was running just fine when it decided to just quit. Nice warm sunny day....