Ignition Coil

[RAMBLINFSJ]

I'm working on my friends '90 Wagoneer. It will intermittently die. Last week it died on me and would not restart. I changed the coil first and it refired. I drove it for a day or two and it died a few times but always eventually restarted. Skip ahead a day or two and the motor wouldn't start at all. The motor dying is so random that I figured it must be the ignition module. I changed it out and the motor fire off. I drive it about 100 feet up to my shop and killed the engine. I went to restart it and nothing. The engine just rolls over. I found the coil (made in China) that I removed the first time and plugged it back in. The motor fired up! I'm kinda at a lose but I keep thinking something is up with the ignition coil. Is there something special about the AMC coil compared to these China made coils the parts store is giving me? The only new ignition part that I haven't put on yet is a pickup coil inside the distributor which I will put on soon. If anybody has a theory to what is going on please tell me. Thanks.

[joe]

I haven't had any problems with the cheap China coils yet anyway. Only one's I avoid like the plague are Acel coils and pretty much anything Acel /makes/sells, it's all junk. Does your coil have conventional screw post and nut terminals, or the horseshoe clip? The horseshoe clips can cause a lot of grief.

[RAMBLINFSJ]

It is the horseshoe. I've been wondering about that too but I've had over a dozen FSJ's and never had a problem with the clip. This could be the one though.

[bigbadjeep]

It is the horseshoe. I've been wondering about that too but I've had over a dozen FSJ's and never had a problem with the clip. This could be the one though.

Had that problem with mine. Took a while to figure out the problem. Snipped the connections off then ran New slip on connections.

[18cherokee]

Mine doesn't have the horseshoe connector bracket thing at all - just a couple of wires with the slip on spade connectors (old post style coil).

[Woodchomper]

Originally posted by Joe
I haven't had any problems with the cheap China coils yet anyway. Only one's I avoid like the plague are Acel coils and pretty much anything Acel /makes/sells, it's all junk. Does your coil have conventional screw post and nut terminals, or the horseshoe clip? The horseshoe clips can cause a lot of grief.

I got burned by an MSD coil that decided to to be a problem after a year of use. Anyway, I didn't realize the coil was made overseas when I bought it. Now I know to be careful when buying MSD products. Attached is a post from 2010 that describes which products are made overseas.

https://www.msdignition.com/forum/showthread.php?t=15381

[serehill]

Hmm the overseas which is 90% of all coills seem to work fine for me.

The Blaster 2 I have on my Cherokee is 6 years old & I bought it used on craigslist!!! I have good service with MSD. I'm sure though you can get a bad coil with any model. Do you know a lot of coils can not be mounted horizontally? Mostly non epoxy & dry types. I wouldn't write off a good brand from one scenario. If they were that bad there would be lots of input on them. I won't use those clip on ones for anything. Everyone I've ever seen are lose clipped. Not my type of connection for a Jeep.
The MSD TFI coil Has been on the Honcho now for only about a year.
I would question the scenario as being a coil anyway. I would suspect the ignition controller for this kind of action. If you're just replacing parts & it's an intermittent problem. Then when you change a part & it runs for a minute but continues to fail It's highly doubtful you replaced the problem.
Be sure to look at the coils mounting requirements.
You might as well park it if your worried about Chinese parts. Almost every re-pop part for these things are Chinese.

[JeepJeepster]

I will say that, for whatever reason, my MSD plug wire set came with an old style plug for the factory coil when the plug wires were meant to be for HEI style plugs. Quick phone call to MSD and they custom made me a coil wire to the length I said and they shipped it to me. Had it in a few days. VERY good customer service. Also threw in 8 spare boots and crimp connectors, but sure why though...

Something else I found out, you CANNOT use the factory duraspark module when you wire in the TFI coil with a relay. Ive not figured out why you cant, but the factory module was sending a constant 12 volts to the coil which overheated it to the point of popping and cracking. It still works great, but I do not trust it so I ordered a motorcraft TFI factory coil.

[Chevelleguy]

Don't forget about the pickup coil in the distributor. It's can give you the same symptoms when it goes out too. Easy to check with an ohm meter when it dies, you just have to do it while it's acting up. IIRC it has a 400-800ohm operating range. If it's outside of this, replace it.

[RAMBLINFSJ]

Well, I won't ever really know what the problem was because my friend wants to install an HEI distributor. I've installed 2 already on my J10 and Rambler and I love them. So he wants to do the same. Thanks for the advice guys. I've learned a little more and I know more of what to look for in the future.

[serehill]

LOL HEI

Now that is a crap shoot.

[Woodchomper]

I can see the attraction of going to HEI for an easy fix but the HEI itself is not without its own problems (cam gear, wiring mods, etc.). If you go the HEI route make sure you get a quality unit. If money is no object take a look at the MSD 8523 distributor. If you go with the 8523 you will still need an external coil though but you will no longer need the motorcraft ignition box since the 8523 has a built in ignition module.

I re-read some of your posts today and I can't help but think you have a wiring problem. Intermittent problems can be a pain to troubleshoot but when you have a condition of no start/run you have an opportunity to find the problem. When you changed the coil the second time and got it to run you also moved the wiring around to install the coil. As said before it could be the horseshoe connector or it could be the surrounding wiring.

Usually when I run into a problem like you described the first thing I do is verify spark coming out of the coil. No spark then verify voltage at the coil positive post with the key in the "start" position (should be close to 12v - wire from solenoid tied to coil feeds additional voltage during start) and "on" position (should be around 9.6V - resistance wire from ignition). You can also manually fire a coil by momentarily grounding the coil negative post too. If the coil fires then that means the ignition module, distributor, and wiring could be the problem. One thing I have done in the past was to just hook up the connector of a spare distributor (dist not installed in engine) and manually turn the distributor and verify the spark coming out of the coil. Anyway, there many methods you can use to troubleshoot ignition problems. It might be worth some of your time to isolate the problem in your friend's wag before throwing new parts into the mix. Good luck and keep us posted on the final outcome.

[RAMBLINFSJ]

Installing an HEI isn't a big deal. I buy mine from CRT Performance. I have one on the 232 in my Rambler and one in the 360 of my J10. Both work great. It was the best upgrade I did on my Rambler. CRT even guaranteed it if the cam gear got chewed up. I used their gear in the Rambler and haven't had a problem in the 4 or 5 years since I installed it. On the J10, I went ahead and swapped the stock AMC gear on the HEI distributor. CRT has a good reputation with me so I wouldn't hesitate to use another one of their distributors. As for the 12 volt keyed power source to it, I just splice into the wire going into the stock ignition module.