CJ MEDEVAC help me with my CJ 7!

1978 JEEP CJ7
1,234 MILES • 5.0L • V8 • 4WD • MANUAL
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DAVY KEITH
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CJ, I see you have a wealth of knowledge and answers on here. First of all, thank you for your service.

I have owned at least a dozen jeeps. I recently bought a 1978 CJ7 with an AMC 304 motor. The previous owner(s) have tweaked the motor, it has a cam. When I first drove it, it sputtered and drove terribly. First mechanic I took it to stated coil was hooked up backwards and they put new coil in and removed, yes removed the resistor! Ran crappy.

Took it to the next mechanic and he discovered no resistor problem and put one inline to the positive side of the coil. I see you mentioned that in another thread that is no go. It ran like crap. Mechanic said couldn't fix it some thing is wrong with the engine.

Third mechanic I took it to, said the problem was that the carb was full of crap! Ran great! until Thanksgiving day! Turned over and it started briefly. I continued to turn it over, several loud super loud backfires (it has cherry bomb mufflers) no crankie. Spark was weak. The next day, I decided to check the coil. Ohm resistance was out of spec so I bought another one and change the coil myself (got one from Autozone specifically for this make and model). There is nothing on the package that says for use with or without a resistor. It's "Hecho in Mehico" duralast. However, in my diagnostic I did check it again.

Okay I am taking a breath and going to let you read this before I get too far into this.
Nov 28, 2016 at 5:48 PM
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DAVY KEITH
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Put that on and still no spark. Well, Ignition control box was only $3.000 at Autozone so what the heck. Changed that too, no sparkie. What I have found that seems to be outside of the diagnostic specs on the coil is that with the key on I have twelve volts to both positive and negative side of the coil! I was thinking it should only have 12+ to one side, the positive side? I have been testing with a test light and a volt meter. One diagnostic test indicated I should check the negative side with the lead of the light to the positive side of the battery and that should light up. Well it doesn't. So I am sure you may have some questions for me thanks a million for your service to our country and your time!
Nov 28, 2016 at 5:51 PM
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DAVY KEITH
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This is the coil I bought: http://www.autozone.com/ignition-tune-up-and-routine-maintenance/ignition-coil/duralast-ignition-coil/jeep/cj5/1977/6-cylinders-a-4-2l-1bl-ohv/111849_0_6007/?counter=0filterByKeyWord=coilfromString=search
Nov 28, 2016 at 5:56 PM
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DAVY KEITH
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The Ignition Control Module is Duralast F102 http://www.autozone.com/ignition-tune-up-and-routine-maintenance/ignition-control-module/duralast-ignition-control-module/118422_986171_0_5133/
Nov 28, 2016 at 5:58 PM
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DAVY KEITH
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I can go outside and measure the resistance in my positive wire to my coil if you need that information.
Nov 28, 2016 at 5:58 PM
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DAVY KEITH
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oh and by the way I can figure things out, I am a pretty smart fellow the reason I was using mechanics is I just do not have a lot of time. However, now that I am in this neck deep I am having to make time and it is a situation where I am going to figure this out come hell or high water!
Nov 28, 2016 at 5:59 PM
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DAVY KEITH
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Oh and I thought about taking the Ignition module back to Autozone to have them test it to make sure it is not bad but I had to cut the plug off because my Jeep is a Frankenstein Jeep. I am very proficient at splicing, worked for my dad at his electronic's business for the first twenty years of my life. Anyway, they could not test it because I cut the plug off, sheesh.
Nov 28, 2016 at 6:02 PM
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DAVY KEITH
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Also, I checked the ohms on my pick up in my distributor, that looked okay, but I will do it again if needed!
Nov 28, 2016 at 6:03 PM
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DAVY KEITH
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Started to buy a new distributor but I figured instead of throwing parts at it I really need some expert advise. http://www.autozone.com/external-engine/distributor/cardone-reman-distributor/jeep/cj5/1979/6-cylinders-c-4-2l-2bl-ohv/768895_76774_0/?counter=0filterByKeyWord=DISTRIBUTORfromString=search
Nov 28, 2016 at 6:04 PM
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DAVY KEITH
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Oh and to advise you how I am testing for a spark. I pulled a plug with the wire on it. I ground out side of plug, no spark. I actually took a wire and completely wrapped it around the plug and ran the other side to the negative on the battery. No spark while trying to crank it. Starter works fine, motor turns over it cannot start without a spark! I do not know much but I do know that!
Nov 28, 2016 at 6:06 PM
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DAVY KEITH
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Picture sorry it is sideways.
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Nov 28, 2016 at 6:18 PM
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DAVY KEITH
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My awesome resistor in line going to positive lead on coil. Have no clue what resistor it is.
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Nov 28, 2016 at 6:24 PM
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DAVY KEITH
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Ignition control from Autozone F102 Hecho in Mexico. I know it is not bolted down and it needs to be for heat distribution and maybe grounding too I just slapped it back on after my failed attempt to get Autozone to check it to see if it is bad. This is the new one I recently bought.
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Nov 28, 2016 at 6:26 PM
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DAVY KEITH
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Picture of motor. Edelbrock carburetor mostly new.
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Nov 28, 2016 at 6:27 PM
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DAVY KEITH
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My illustrious distributor looks mostly new probably is I do not have the history on it. Inside is pretty everything looks brand new on the inside. Plug wires are newish, checked resistance on a couple, especially the one going from coil to distributor and it checked okay.
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Nov 28, 2016 at 6:28 PM
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DAVY KEITH
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Picture of her from the side, she is pretty but has a few rotten teeth underneath. Someone spent more time on the outside than all the rust down below.
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Nov 28, 2016 at 6:30 PM
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DAVY KEITH
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Better picture of motor.
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Nov 28, 2016 at 6:31 PM
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DAVY KEITH
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My daughter in the Jeep. She wont ride it yet says it scares her. Not going to let her until I get seat belts, yeah really whomever had this had zero seat belts. Probably needs a new steering box as it is a constant back and forth on the steering wheel and I would like to either lower it or maybe get spacers to have it sit wider on the road? I need to make it a little safer as it concerns me sitting up so high, easy roll over.
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Nov 28, 2016 at 6:34 PM
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CJ MEDEVAC
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Do you have an OEM distributor or has it been changed?

Have you looked at the fuses?

Do you know how to run a continuity test w/ your voltmeter (like thru a light bulb)?(I can show you if need be)

1976-1978 used "Prestolite Ignition", Is this what you still have?

Prestolite did not use a resistor wire or a ballast resistor- the OEM coil (or aftermarket the same) will be the correct coil.

Where are you buying parts? I can look at what you are getting/ or need on their site

I really need to know what is modified and not stock on your engine.

Please try to answer all of my questions, sorta makes things go smoother and faster!

The Medic
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Nov 28, 2016 at 6:36 PM
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CJ MEDEVAC
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Please slow down!

Let me catch up!

The Medic
Nov 28, 2016 at 6:40 PM
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DAVY KEITH
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Lol... I have more! Just been waiting for you so I thought I would keep posting.
Nov 28, 2016 at 7:02 PM
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DAVY KEITH
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Pretty sure that I have an electronic ignition, ie not Prestolite.

Fuses I think I am past that stage. I know I have power to coil with key on.

Dad taught me how to use a volt meter around eight years old, we are good there.

Parts are Autozone.

Engine has an Edelbrock carburetor. Engine has had some internal work, at least a cam. Other than the valve covers which are also Edelbrock. I have no clue what has been done to the engine. I got it from someone who got it on a trade. Supposedly it dynoed at 400hp but I kind of doubt that. Feels more like 200 hp
It is a strong engine, but not some kind of crazy beast.
Nov 28, 2016 at 7:24 PM
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CJ MEDEVAC
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Mr. Distributor.

Have you pulled him out/ even up at all, your distributor after it ran well?

Have you pulled the distributor cap and watched the button turn while being cranked?

Try to firmly/ gently turn the rotor button with your fingers (engine off!) Will it turn a lot under pressure (a little CW and CCW movement is normal) Just making sure the drive gear pin is not sheared.

You now have a Motorcraft ignition (introduced to CJ's in 1979)

You need a coil for a 1979 (no internal resistor)

and a ballast resistor ( as the 1978 did not have a resistance wire-but the 1979 did!)

Are you wired as I show in my pics below? This is from a 1979 wire diagram. Let's check it good!

Showing a continuity test for distributor also.

(I upgraded my 1977 to Motorcraft too, Too many quirks with the whole Prestolite deal that left me stranded too many times).

Still got the good old mechanical fuel pump on your engine?

This may all be a review, but we have to know we have not missed something stupid!

The Medic

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Nov 28, 2016 at 8:21 PM
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DAVY KEITH
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Medic, I will check the distributor. What about twelve volts being on both sides of the coil, is that correct? Could you advise where to get that ballast resistor? I will check everything in your pictures as well. Is the coil I linked you to the correct one? Mechanical fuel pump. I know it is getting fuel my issue is no spark.
Nov 29, 2016 at 6:46 AM
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DAVY KEITH
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CJ Medevac, which of these ballast resistors do I need? http://www.autozone.com/batteries-starting-and-charging/ballast-resistor
Nov 29, 2016 at 9:05 AM
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DAVY KEITH
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CJ Medevac, I am wondering if I have the wrong coil. I have this one http://www.autozone.com/ignition-tune-up-and-routine-maintenance/ignition-coil/duralast-ignition-coil/111849_576402_17367/?fromString=search&make=&model=&year=&checkfit=true which is the one for a 1978 Jeep CJ 7 and based on what I am reading from you, I need one for a 1979 CJ7 which is showing this one w.autozone.com/ignition-tune-up-and-routine-maintenance/ignition-coil/duralast-ignition-coil/111930_576402_17367/?checkfit=true

Neither one indicate whether it's for use with or without a resistor.
Nov 29, 2016 at 3:18 PM
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CJ MEDEVAC
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Just got home from work,

Looking over your stuff now.

The Medic
Nov 29, 2016 at 3:26 PM
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CJ MEDEVAC
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This is the one that it calls for on a 1979.

http://www.autozone.com/ignition-tune-up-and-routine-maintenance/ignition-coil/duralast-ignition-coil/111930_576402_17367/?checkfit=true

Ballast resistor-

.8 or .85 OHM will work,

"i Believe"- Well all of them have a pocket on the backside in which the resistor coiled wire is in.

The ones that are wide open tend to let the coiled wire maybe bounce/ move about while you are bouncing the Jeep on the road.

To me these seem to fail/ coiled wire breaks- Jeep is now dead in the water

I think the one I got last was from NAPA auto parts, It had ceramic/ or something poured over the coiled resistor wire (like a ceramic cover over pocket) I have had this one a long long time.

If you can find it anywhere, try to go with that type (OHMs the same as I mentioned) Online pics may keep you from traveling everywhere!

Should you become dead in the water, check the ballast. Just to get you in, you can temporarily bypass the ballast using a Jumper Wire/ Tying the two wire together/ use a "Piggy back" (Picture Below). Put the piggyback on one side and leave it there until you need it. Going this route, it is just "plug and unplug". Nothing' else needed! Get a new ballast soon so that everything is back to normal!

What part of the country are you in?

The Medic


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Nov 29, 2016 at 4:04 PM
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DAVY KEITH
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I am in South Mississippi. The rotor arm turns in the distributor when I turn the engine over (you asked about that). I called my mechanic today and told him about the situation. The first thing he said was to make sure the Ignition Module has a good ground. It seems to me that the only ground it has (besides being bolted to the fender well) is the distributor ground which as I understand it is a different ground than common ground? Anyway, I am running new wires right now to confirm everything is hooked up correctly.

So the orange and black wire coming out of the fuse box, connects to the ballast which in turn connects to the positive side of the coil. It will also have a direct connection (without ballast) to the red wire on the ignition module if my math his correct here.
Nov 29, 2016 at 4:14 PM
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DAVY KEITH
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CJ Medevac, I may have found part or all of the problem.

I have no power on green wire that goes to the negative side of the coil with ignition on while putting the other side of a test light on the positive side of the battery. My understanding is this is how you check to make sure the coil is grounded through the distributor.

I checked both the ground wire to the dist and green wire back to ICM and both have continuity. One note, the ICM is not mounted on the fender at this time. Does it have to be to get a common ground? Where is the ground for the ICM? This is the first thing my mechanic asked me, where is the ICM grounding and check that.
Nov 30, 2016 at 2:56 PM
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DAVY KEITH
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Ok, progress made. I've got a spark, albeit a weak one. I put the old ICM back on. Green wire passed diagnostic by lighting up test light when I put the other side of the test light on the positive side of the battery. The plug makes a spark but intermittently and weak. This was the reason I changed the ICM in the first place! It wouldn't start and once I checked the plug I noticed it was weak. Turns out the new ICM was bad! The old one may be bad too and cause the weak spark. Going to get away from the Auto Zone one and pick one up from NAPA tomorrow.

Another interesting note. The red w/ black striped wire coming off the side of the solenoid wasn't hooked to jack crap! I spliced it into the red wire going to the coil. I have so many wires I pulled out of the tubing it looks like a spider web all of the top of the motor. Bound and determined to get this started!
Nov 30, 2016 at 4:27 PM
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CJ MEDEVAC
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Don't worry about the negative side of the coil (for now)

Everything else look EXACTLY like my diagram? Wires going all the way to components as shown?

You need to mount your ignition module on the fender

Scuff a dime sized bare spot around the bolt holes

This puppy gets grounded by the case.

Beings that I had Prestolite before (like you did-I think), The newer Motorcraft Ignition Module was not even there to mount!

I had to mount mine out of the way of my three train horn bugles.

I'm gonna dig thru some of my pics (another 2car clients pics) I'll post one of where theirs was originally mounted.

Pic 1) Module right beside the windshield washer bottle.

Next paragraph is taken from a 2010 answer I gave (Given it many times since then too!)

"It could be that your Ignition Module is bad (either system). Test old one at Autozone or Advance Auto for FREE, Test 5-7 times in a row and quickly, this heat up its guts! If it fails once (That is after the Tech figures out the correct plugs and settings) REPLACE IT, TEST THE NEW ONE THE SAME WAY BEFORE YOU LEAVE! TRUST ME. No matter what "THEY" say!"

You are doin'good, even without me!

Keep it coming.

Is that Grabber Blue on your Jeep!?

The Medic
Nov 30, 2016 at 5:48 PM
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DAVY KEITH
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dAMMMITTTTTTT!!!! New Duraspark box (SECOND ONE AS FIRST AUTOZONE ONE DIDN'T PASS ONE OF THE DIAGNOSTIC TESTS LISTED BELOW) and still weak spark. aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhhhhhhhhh hhhhhhhhhhaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaa.

I'M AT WITS FREAKIN END WHAT THE MOTHER OF ALL JEEPS IS WRONG WITH THIS PIECE OF SHIT

I did this complete diagnostic check listed here: http://www.jeepforum.com/forum/f8/86-cj7-i6-stalled-power-coil-but-no-spark-936569/

EVERYTHING passes 100% and continuity is good between everything. I've got a new coil, a new resister, a new Duraspark NAPA box and I've soldered every connection! When I crank the engine the spark is weak and intermittent (not consistent). The only thing this could be at this point is the distributor I suppose because there is not much left to check!
Dec 2, 2016 at 6:37 PM
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CJ MEDEVAC
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Maybe it's like Ford stuff, change in mid year.

Did this come with Motorcraft of Prestolite?

If it were Motorcraft, maybe it has a resistance wire (no need for the ballast) Can you test the wire to see if it is a resistor wire (or have you replaced it with a regular wire?). I'm suggesting may be that the needed resistance has been doubled (I'm guessing).

Try this! AS A TEST

Pos battery to Pos coil

See my 1st two pics, see if spark improves

Temporarily disconnect "I" at solenoid, maybe solenoid is somehow dragging it down

You tested this puppy at an auto store? Pics are of Advance Auto Parts Machine

The Medic
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Dec 2, 2016 at 7:04 PM
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DAVY KEITH
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Hey CJ Med, I have no idea if it's motorcraft or presolite. This is a frankin jeep cobbled together by the last owner. I can guarantee there is no resistance between the Red wire from the ICM to the pos of the coil. Why? I ran the wire straight from the red / blk out of the firewall to the coil. I did put a ceramic resister in .7 Ohm but it's weak and intermittent either way. I'm thinking it still may be the coil. The coil I have I got for a "78" CJ7. If I recall correctly, you mentioned I need one for a 79 due to the ignition upgrade to electronic. I ran the diagnostic on the coil for the 79 and the resistence is the same so would this mean the coil I have would work anyway? Ugh my mind is spinning. http://econtent.autozone.com:24999/znetcs/psb/en_US/2/0/27/c832_coil_specs.pdf
Dec 2, 2016 at 7:22 PM
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CJ MEDEVAC
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Roger on the wire. Definitely no resistance if you ran it!

Affirmative on the '79 coil it is for electronic ignition. Your module that you have is for '79-early 80's

Just a note- prestolite is also electronic (I reckon more primitive and crappy design)

Keep it coming-Good luck!

The Medic
Dec 2, 2016 at 7:38 PM
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DAVY KEITH
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Ran the hot wire to hot side of coil. Didn't crank but I didn't take a plug out to see if it was sparking better I'm through with this POS for tonight. Man this is so aggravating.
Dec 2, 2016 at 7:40 PM
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CJ MEDEVAC
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It's a CJ

It needs TLC!

If you have an old plug, you can just snatch a wire instead of removing a plug!

Talk sweet to him, he didn't do this to himself.

I'll be putting new leaf spring bushings in "Mr. Jeep" tomorrow. Polyurethane is junk, lasted 8 years, then sorta started crumbling away all at once. Going back with rubber ones. The fixed ends of my leafs are scooching back and forth in the perches when I make turns. I'm noticing it is giving me a teeny bit of 'extra' steering when I apply the brakes.

Maybe a little sleep will get you in the groove.

Nite Nite

The Medic

Dec 2, 2016 at 8:58 PM
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CJ MEDEVAC
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Lets hear some good news!

The Medic
Dec 20, 2016 at 5:40 PM
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DAVY KEITH
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I tried everything I could think of: New coil, new ignition module (two of them), new wires, dist cap, rotor button arm, pick up, grounded ignition module, new ballast resistor, even jumped 12 v directly from battery to + of coil. Spark is intermittent not solid. The only thing I didn't change was the entire distributor but it was turning so I didn't see the need to do so. Took it to a mechanic.
Dec 21, 2016 at 9:33 AM
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CJ MEDEVAC
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Please do let me/ us know what the deal is/ was.

I'm sorry I did not get him going.

I know you will be happy to get to drive him again.

I know how it is when you are suddenly Jeepless. Makes you wanna cry (well maybe I did just a little bit anyway)

Maybe you'll get him back by Christmas, then you'll have a Merry one!

The Medic
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Dec 21, 2016 at 3:04 PM