Sudden death, no spark

[Escobarclan]

Hi guys. My Son's fist vehicle, a 1980 CJ5 Iron duke died on the highway. Just plain died outright. We have no spark at the plugs.

I haven't worked on these Iron Duke ignitions, so where could I start? How can I diagnose the coil, module, pick-up, condensor? Has a new cap, rotor, wires, and plugs.

Any help would be greatly appreciated.

 

[CJim7]

Ignition control module

 

[Torxhead]

Like CJim states it could be an icm, another possibility would be that coil. It should get 1.35 ohms across the (+) and (-) terminals and the pick up coil in the distributor should get 600-800 ohms between its two terminals out of the dist. Most guys just trash the condenser when it goes, all it does is smooth out spikes from the coil anyway.

 

[Escobarclan]

Ok thanks guys. Getting knee deep into it right now. RockAuto here I come.

 

[Escobarclan]

Ok, coil showing 1.4Ohms- good.

Pick up showing 812- ohms- meh......ok I guess. Glad because it looks like a pita to change.

ICM going to Autozone to test. Not sure if condensor can be tested.

With no ignition, is there ANYWHERE else I can look for a problem, just in case the icm tests ok?

 

[IOPort51]

If you lost the ground on the ECM

 

[Escobarclan]

Ecm? Where's that at? Didnt know it has one......

 

[Escobarclan]

Ok, icm tested fine, coil fine, pick up, fine. Ballast resistor, fine.

Only thing left is the condensor. Any way to test that. Totally stumped. Btw I am getting main power to the dist.

 

[Lumpy Grits]

Condenser- You don't have a point-type ign do you?
If no points-it's for RFI only. It runs better without it.
Try this-Run a wire from the POS(+) side of the battery to the POS(+) side of the coil. Will it start now?
Don't run it long like this--
Pull this wire to shut down engine.
LG

 

[mtnwhlr]

I'm going to send you in a differant direction, Timing chain.

 

[Lumpy Grits]

Think if it was the TC there would have been much'o engine damage.
LG

 

[Escobarclan]

If it was timing chain, that would throw off the valve timing but the spark plug would still spark when grounded, a timing problem would throw off the valves and engine wont run right but I would still get a spark at the plug, right?

UPDATE:

Ok, found a bad connection at the dist main hot wire. Fixed it. Now I'm getting a very weak and only intermittent spark at the plug.

What exactly does the pickup do, work to advance or retard timing? Could it weaken a spark?

 

[Lumpy Grits]

Chg your battery, and try again.
LG

 

[Escobarclan]

Showing 12.46v but I'll do it to eliminate any doubt. Good point.

 

[Torxhead]

I see you are right at the limit of the pickup coil, I would say that its life is Limited. A good way to replace it would be to get a remanufactured distributor like the one Crown makes. Another thing you can check on that pickup coil is to make sure that the two wires coming out of it are not making any ground contact. Like either wire, orange and violet I think, can be tested with your resistance meter. The third black wire is to ground the icm, which is critical for it to hold up.

 

[Goatboy4570]

I see you are right at the limit of the pickup coil, I would say that its life is Limited. A good way to replace it would be to get a remanufactured distributor like the one Crown makes. Another thing you can check on that pickup coil is to make sure that the two wires coming out of it are not making any ground contact. Like either wire, orange and violet I think, can be tested with your resistance meter. The third black wire is to ground the icm, which is critical for it to hold up.

Hes not running duraspark the Duke 2.5 is a chevy motor. i think his pickup coil wire are yellow

 

[Goatboy4570]

If im n mistakin they used the iron duke for just a few years in the cj but fear not chev and pontiac put millions of them in S10s 15s astro vans and god knows what else, parts new an used should be cheap and plentifal.

u may be able to buy a whole distributor for 30 bucks. the ignition is preety reliable but the main computor and electric feul p/p are nt ot.
also theres a 3 amp fuse to ecm that carry aux power that can blow that took me out once and the ecm failed on me once too, used one from a 87 camero that time the ecm's dont like to be mounted in a poorly vented spot running hot.

The pickup coil pulses the icu which sends a amplified voltage pulse to the coil to fire the plugs . the system needs full power and good ground to work properly. keep the questions comeing

 

[Escobarclan]

Great advice guys. Never had an Iron Duke before. My other CJ's have all had a 258 straight 6 and my first Jeep had a 304 but that was 22 yrs ago.

This is my Son's first CJ and this engine is a new experience for both of us. However, it does not have an ECM.

I'm going the swap the pick-up just to be thorough. It still has an idling problem that is most likely caused by the carb but I have to rule it out.

Btw, finding a replacement carb for this engine looks like a pain. It is very confusing online when looking for a better replacement.

 

[Hedgehog]

I had a small Holly on mine. Worked well and was better after the power valve was changed.

 

[Escobarclan]

Where'd you get it?