MSD Blaster II Coil Getting extremely hot and failing.

crzdmnky · 07-18-2010, 02:13 PM

I went out last night and had a little trail riding, and on my way home my driveshaft decided it had enough and decided it wanted out of its serious relationship with the CJ. So it found its way out, but I was already slowing down and stopping, so no injury there. Jeep soon after died because of the heartbreak, and failed to want to start again afterwards.

Anyways I couldnt get it started back up, and when I popped the hood my MSD Blaster II coil was so hot you couldnt touch it. And when tried to start again, the jeep made a loud pop out the exhaust. After letting it cool down the jeep started no problem.

Anyways when hooking up your Blaster II coil to the stock ignition system. Do you need any type of resistors between it and the ignition control module or anything? I dont want to go buy another $40 coil and have this same problem again. Any advice or knowledge on this subject would be much appreciated. Thank you for your Time

Aaron

Chuckles0227 · 07-19-2010, 02:25 AM

was your key left on? mine will heat up like that if the key is on and the engine isn't running. also make sure the wires are hooked up correctly on my friends rover he had them backwards and it would just over heat the coil. I don't think you need a ballast resistor or anything, i don't have one with my stock ignition.

crzdmnky · 07-19-2010, 02:16 PM

It is extremely hot after driving. They arent suppose to get sizzling hot. Plus my Tach starts to jump around now too.

Chuckles0227 · 07-19-2010, 02:21 PM

did you get the blaster coil that uses the stock coil clip for wiring or did you just throw ring terminals on and hook it up that way? on my friends land rover he had the wires hooked up backwards and it would over heat the coil and then it would start to run rough.

crzdmnky · 07-19-2010, 02:39 PM

I threw some terminal ends on it. It has a positive and negative side on it, and it doesnt run rough at all. Just it failed to start the other day, and the tach is beginning to mess up, and the coil is apparently getting way to hot. I have also went thru about 3 ignition control modules. This is why I am asking if there is suppose to be something inbetween the coil and control module. Its not cheap having to replace modules and coils.

sprag44 · 07-05-2011, 07:48 AM

Did you finally figure out the over heating coil problem? Mine is doing the same thing. I just joined the Jeep Forum for some help on this. I'm sure I will need help on other things but this is the current one.

**JeepHammer** · 07-05-2011, 08:23 AM

Quote:

Originally Posted by crzdmnky

I went out last night and had a little trail riding, and on my way home my driveshaft decided it had enough and decided it wanted out of its serious relationship with the CJ. So it found its way out, but I was already slowing down and stopping, so no injury there. Jeep soon after died because of the heartbreak, and failed to want to start again afterwards.

Anyways I couldnt get it started back up, and when I popped the hood my MSD Blaster II coil was so hot you couldnt touch it. And when tried to start again, the jeep made a loud pop out the exhaust. After letting it cool down the jeep started no problem.

Anyways when hooking up your Blaster II coil to the stock ignition system. Do you need any type of resistors between it and the ignition control module or anything? I dont want to go buy another $40 coil and have this same problem again. Any advice or knowledge on this subject would be much appreciated. Thank you for your Time

Aaron

Your Bio says '77 CJ.
If you are talking about that '77 CJ, and you have the stock Prestolite distributor and Stock Prestolite Ignition module I'm surprised it's lasted this long!

I'm also surprised the module lasted this long!

You do know the blaster coils and the Prestolite ignitions don't get along very well?...

Anyway, you DO need a resistor with the blaster coils when used with Prestolite ignitions...
1.35 Ohm or larger.

You might also want to check to see if you engine cylinder head is grounded...
A poor electrical 'Ground' to the head will cause coils to fall by the way side rather quickly, same with ignition modules...

Ever considered converting your current ignition over to something a little more 'Main Stream' that works with more than just Prestolite products?

sprag44 · 07-06-2011, 07:42 AM

Sorry, I did not update my profile. I have a 1985 Cj-7. I have been through a coil and 2 ignition control modules. My son had it and left the key in the run position and it wouldn't start. I have since learned in my searchs here that will cause the problems. I am paranoid now since I fixed it that the coil is too hot but it runs good. I cleaned the ground wires and connector to the block/head on the right side of the engine. When i did this I noticed a ground wire that was black with a white line that used to be grounded there (same size washer mount) that the previous owner must have removed,folded back and taped out of the way. Shouls I re-ground it? I have the Jeep manual with the wiring schematic and do not see this ground wire. I have not traced it though. The coil is hot for sure but how hot does it get under normal use? I can't hold it after driving.

**JeepHammer** · 07-06-2011, 08:21 AM

Coils can fail because of two things,

One is NOT using a resistor when you should, but with an '78 newer vehicle that resistor should be in the harness as a 'Resistor Wire' unless you took it out for some reason it's still there and working or the ignition wouldn't run at all.

The second reason, and most common for coil failure is POOR GROUNDING TO THE ENGINE HEADS.
There are LOTS of bolts and stuff between head and block, but those bolts are ALWAYS coated in crap when you pull them,
So direct grounding of the head so the high voltage discharges can properly to go 'Ground' in the heads is a good idea.

The WRONG COIL will often overheat on the factory ignition module.
Those 'Super Duper' coils claiming huge output voltages are the worst!
They REALLY sacrifice Amperage & Duration to make large voltage numbers, and they overheat in the process.

EVERYTHING ON THE 'PRIMARY' SIDE OF THE IGNITION SUFFERS WHEN THE MODULE DOESN'T HAVE A PROPER 'GROUND' CONNECTION.

Since the module TRIES to 'Ground' through the distributor housing, and the engine block often doesn't have a reasonable 'Ground' it's self, the module often fails because the block isn't grounded correctly/properly/sufficiently.

A dedicated 'Ground' wire to the engine head, then over to the 'Black' wire on the ignition module will usually help with the ignition issues when talking about 'Grounding'...

Now, leaving the key in the 'Run' position is certain death to the module, and usually doesn't do the coil any good either...
Both are 'Hot' when the key is in the 'Run' position, and they WILL overheat and damage/die if it's done too often or for too long.

Teach EVERYONE that gets into that vehicle about the 'ACC' or 'Accessory' position on the key switch so they don't kill the module/coil...

sprag44 · 07-07-2011, 07:57 AM

Thanks for the help. Appreciate it.