HELP! Ignition coil keeps blowing. What should I do?

[NewYorkerFan]

I have a 1988 Chrysler Fifth Avenue (with a 318 V8) and my ignition coil keeps blowing. I don't know what happens but every 3 weeks or so I am left stranded. I had the car converted to the old style electronic ignition system from the Electronic Spark Control computer with the kit from Mopar. It was fine for over a year. Then started having problems. I would start losing spark. As soon as I change the coil its cool. I am using Canadian Tire cheap coils though. Not sure if that has anything to do with it. I am really at my wits end with this thing. Thinking of scrapping it because its driving me nuts. Is there any tricks or tips? I am going to try order an original coil from Mopar performance instead of these cheapies.

Should I mount it in a different spot or rewire it somehow? Or is there something else that could cause this problem? Any advice would be amazing as I cannot find any info on this.

[orgvcregal]

I think you may be using the wrong coil you would be using a ballast resistor so make sure the coil you get is for a ballast resistor or get your wiring checked out.

[cageman]

Hmm, the coils on thsoe cars mount straight up and down, so that shouldnt be a problem, and oh so easy to get at too, I would scrap the car too after two or three coils too, LOL
Just switch coil brands and try that.

[NewYorkerFan]

Originally Posted by orgvcregal

I think you may be using the wrong coil you would be using a ballast resistor so make sure the coil you get is for a ballast resistor or get your wiring checked out.

OH REALLY! I didn't know that a 1988 coil wouldn't work for a ballast resistor. The ballast resistor was added with the kit but I have been ordering coils for 88 when they never had a ballast resistor. So that may be what is happening. Is the coil just not strong enough? This never happened with the original one, at least for a year. Usually when the car has been running for a while and gets hot it blows. One time oil came out the top of one of them. So I better get the original coil from Mopar performance.

So ignition coils are not all the same then?

[NewYorkerFan]

Can anyone confirm that some ignition coils are not designed for use with ballast resistors? I really need help with this. This is life and death for my beauty. If I can't figure this out I have to scrap her.

[aarracer]

Not the first time there has been a bad run on outsourced parts! Go to another parts store and get a "Blue Streak HD" unit and you should be cured. Do not get a mopar Mexican unit, you may experience the same problem. Probably NOT a ballast resistor issue.

Go back to Canadian tire and get a cash refund!

[Walkercolt]

Very,very few coils are designed to be used without any ballast resistor. The proper ballast resistor is determined by the primary resitance of the coil. A "stocK" type coil will have about a 3 Ohm resistance. An MSD racing coil(or Mallory or Accel) may only have .3 Ohm resistance. Huge difference in the current draw, and heat they'll handle. The ballast resistor acts as a current regulator. More sophisticated electronic ignitions have circuits to limit the current. Get a Mopar coil and install the ballast resistor in the kit as shown, and you shouldn't have anymore problems. Your "no-name" coils are getting too hot from too much current without a ballast resistor and melting down. This will keep happening without a ballast resistor, and may keep happening with the more powerful than stock electronic ignition. I think a Mopar coil is about $30 US, or find one in a salvage and pay $5 to have it checked. They're usually good after sitting for 30 years or more. Either with a ballast resistor or a "smart" ignition box, you have to limit the current to the coil as it heats up. No way around it. You don't have a "smart" box, so you need that ballast resistor, or an exspensive "racing" type coil, and there's no reason to go that way for a street car. I had a '74 Ddoge Dart with electronic ignition. Standard "black" ignition box, white resistor beside it, never had a problem with it.

[valiant64]

Get a coil designed to work with your electronic ignition & be sure to get the ballast thats recommended for it. Really, it does sound like you've ended up with some weak coils though. 1 every 3 wks or so? Argh! Hope you get it sorted out!

[orgvcregal]

Originally Posted by NewYorkerFan

OH REALLY! I didn't know that a 1988 coil wouldn't work for a ballast resistor. The ballast resistor was added with the kit but I have been ordering coils for 88 when they never had a ballast resistor. So that may be what is happening. Is the coil just not strong enough? This never happened with the original one, at least for a year. Usually when the car has been running for a while and gets hot it blows. One time oil came out the top of one of them. So I better get the original coil from Mopar performance.

So ignition coils are not all the same then?

I'm not an auto electrician but when ever i bought a coil they usually ask if i have a ballast resistor and the coil is normally marked to run with ballast resistor anyway i think Walkercolt advice is pretty good so it should help you.

[NewYorkerFan]

Thank you guys. I will try get a performance coil. I am currently running the single ballast resistor that came with the kit. So I'm not sure why every 2 or 3 weeks the damn thing blows. Some mechanic told me to check the ground straps to the bracket but they are ok. I also removed that radio suppression capacitor on the coil mount. Didn't help because it blew again. I would rewire the whole damn thing if it would fix the problem. I also tried 2 different ECU's thinking it may have been causing the problem.

The coils must be just crap. Can't think of anything else. The ballast resistor never blew yet through all this just the coil.

[Walkercolt]

I'd think a stock Mopar coil would work, but you could step-up to like a Petronix or Accel, MSD, Mallory or other "potted" round coil instead of an oil-filled coil. Those coils usually have thier own recommended ballast resistor, so use that with them. I'd check all my grounds, especially any you've added. Scrap off the paint then use 220 or 320 grit sandpaper. And check your distributor to block ground. Oil and grease make pretty fair insulators. Way too many people have done this conversion without trouble for something not to be 100% right. You can take your black box in and have it checked. It could possibly be bad from the factory, but usually then you have no fire. Stupid question: Are your ignition wires new? Old ones can break-down and "fire" can run-down the outside of them to any ground. You can see this best at night. Double-check that your distibutor cap doesn't have any carbon tracks on the insides(doesn't the kit come with a new cap and rotor?). The RF suppessor capacitor shouldn't make any difference. If it's bad, it'll bulge or burst.

[NewYorkerFan]

Originally Posted by Walkercolt

I'd think a stock Mopar coil would work, but you could step-up to like a Petronix or Accel, MSD, Mallory or other "potted" round coil instead of an oil-filled coil. Those coils usually have thier own recommended ballast resistor, so use that with them. I'd check all my grounds, especially any you've added. Scrap off the paint then use 220 or 320 grit sandpaper. And check your distributor to block ground. Oil and grease make pretty fair insulators. Way too many people have done this conversion without trouble for something not to be 100% right. You can take your black box in and have it checked. It could possibly be bad from the factory, but usually then you have no fire. Stupid question: Are your ignition wires new? Old ones can break-down and "fire" can run-down the outside of them to any ground. You can see this best at night. Double-check that your distibutor cap doesn't have any carbon tracks on the insides(doesn't the kit come with a new cap and rotor?). The RF suppessor capacitor shouldn't make any difference. If it's bad, it'll bulge or burst.

Well why is it important that the coil have a ground strap on it anyway? Just wondering. Also what are potted coils? I think my wires are fine, I even put a new cap and rotor on and new coil wire to try fix it before. There is simply no spark coming out of the coil. The problem is the coil but the question is why. I have a broken ground strap below the car from somewhere but its not from the coil. I don't know what its from. I just wrapped it up underneath.

[orgvcregal]

Do you have a spare module so you can test it because it could also be the module isn't putting power to the coil just a thought good luck with it.

[cageman]

There is a bunch of grounds on those cars, could be the one that also hooks to the head and to the firewall, and I think it goes down to the frame rail, does it have a ring terminal, or a clamp type end that would slide over a pinch weld on it.
A coil doesnt need to be grounded, whoever told you to do that stay away from wehn you need auto advice. Just nod your head and walk away.

[dgc333]

Originally Posted by cageman

A coil doesnt need to be grounded, whoever told you to do that stay away from wehn you need auto advice. Just nod your head and walk away.

Boy that is harsh, especially since you are mostly wrong!

The (-) terminal of the coil provides a path to ground through the points for the primary windings or the switching transistor in an electronic control module. The end of the secondary windings opposite the the plug wire connection is internally connected to the (-) terminal and that provides the ground path for the secondary.

4cyl motorcycle coils, distributorless 4cyl car motors and the coils used on the new mopar hemi do not have the secondary connected to the primaries ground. Both ends of the secondary are connected to spark plugs so the ground path is across the spark gap on both plugs. That is one plug sparks to ignite the mixture in one cylinder and the other spark is wasted in the exhaust stroke of the complementary cylinder.

Now the canister of the typical oil filled is not part of the electrical circuit and wheter it is grounded or isolated makes no difference.

[TK]

Now the canister of the typical oil filled is not part of the electrical circuit and wheter it is grounded or isolated makes no difference.
__________________

I thought you said he was mostly wrong. The Coil itself, does not need to be grounded.

[Walkercolt]

OK, a "potted" coil is filled with an epoxy resin instead of oil. They are designed to stand more heat internally, and can be mounted in any position. I asked my "auto electric guy" about your problems. He's quite surprised. Are you sure your ballast resistor is wired into the circuit correctly? If you're burning up coils then your module should be putting voltage into the coil. Is the plug on the front of the black ignition module plugged in securely? No loose wires or connections? In the instuctions for the new electronic ignition, does it say what the primary resistance of the coil should be? Typically, 3 Ohms is a stock type coil, and "high performance" coils have much lower primaries. I thought the Mopar electronic igniton unit calls out a part number for the recommended coil from Mopar. Unless you've somehow gotten some 6 volt coils, or two turkey's, a coil from a GM, Ford, Mopar, Massey-Fergison tractor should work. This ain't rocket-science or brain surgury or shouldn't be. Do you have an Ohm-meter? Check that the ballast resistor has resistance and it isn't bad. Auto-Zone, Pep-Boys, most anyplace can check it for you. There just aren't that many things that can be bad.

[JVMopar]

Could it be a defective ballast? Possibly it's shorted inside? Just a thought.

[Walkercolt]

Yes, not hard to check, not expensive.

[JVMopar]

Are you running an orange box? The one that came with my kit was junk. Would through a continous spark (no foolin) you could hear it buzzing. Just another thought.

[Century Cp Guru]

You mean Orange box? also check the Ohms on the Ballast and Mopar Lists them in the Perfmance Book they maybe even in a set of instrucions With the Conversion kit And Lean Burn cars had a Single Ballat from Factory.

[dgc333]

Originally Posted by TK

I thought you said he was mostly wrong. The Coil itself, does not need to be grounded.

A coil most certainly does need a ground every electrical circuit needs a ground (or a return path) to function. No the housing doesn't need to be grounded.

Cageman made a pretty strong negative statement about the competence of someone that suggested a coil needs to be grounded. He made no distinction between the electrical requirements of a coil to function and the mechanical construction, that makes him mostly wrong in my book when someone is trying to learn about his ignition system and fix a problem.

[Century Cp Guru]

Wtg Mr Clement. Hows thing on the South shore today.

[dgc333]

Originally Posted by Century Cp Guru

Wtg Mr Clement. Hows thing on the South shore today.

Started out with freezing rain this morning but its just rain now and its melting away the snow from last week.

Are you from the south Eastern Mass area?

[aarracer]

Most early factory coil brackets have a threaded tang that a ground screw is threaded through and up hard against the coil body.

[cudabob496]

Coil is discussed in the below discussion:

Tech Question
Erik Bakko, Brooklyn, NY, 72 Dodge Swinger 318ci

Dear Mr. Mopar Guru,

My ballast resistors have an expected life span of 3 months in my Dart. I put 4000 miles on the clock in the last year. I'm not sure what this little gem does exactly, I just know that it protects other ignition circuits and I'm shot down without it.

Standard Ignition Products rate theirs as "universal". I've burned out two of those.

Mopar Performance has three different models (0.25, 1.0 and 1.4 ohm) Haven't tried these.

I just found my new Mallory cracked in the middle yesterday. Super glue, zip ties and positive thinking are keeping me up and running. This was supposed to be rated for 0.75 - 1.5 ohms and offer variable resistance. Seemed substantial enough but it may have cracked last weekend when I drove in a downpour on the highway for 5 hours. I'll ask about phantom dash leaks another time.

The car has a fresh'nd 318 with a new Mopar orange ignition box, 50 amp alternator, stock distributor, new Mopar voltage regulator, MSD Blaster 2 coil, new Moroso wires and Accel plugs. Other than that, nothing much is different than stock with the ignition. It starts and runs beautifully.

Please offer any thoughts you may have and what I might do to avoid having to waste my time thinking about this little piece of pottery. I just want to know what it does and get one (and a spare) that works.

Erik, first, I need to know what the battery voltage is at 2,000 - 2,500 RPM. If it is much over, say, 14.2 - 14.5 volts, that's part of the equation Offhand, the Blaster 2 coil, which, I belive, is designed for C-D or MSD ignitions systems, probably draws too much current when used in a simple switch-type electronic ignition (such as yours). Swapping to a stock coil and stock ballast would be the easy fix.

Otherwise, you're probably exceeding the 20 or 25 watts dissipation most ballast resistors are likely rated at. The only fix at that point would be two fairly high resistance ones (>1.25O ) paralleled or 2 low- resistance ones (approx 0.5O) in series -- either would do the trick. But, with the Blaster coil, the "Orange Box" is almost certainly handling more current than it is designed for and is next in line to take a bullet.

There's only one other thing I can think of: Possibly you have some wiring error so that the ignition-run circuit (the ballasted one) is also feeding something else; therefore, too much current would be flowing through the balllast. The test: disconnect the ballast and be sure no other circuits have stopped working.

Rick

[cageman]

Originally Posted by dgc333

A coil most certainly does need a ground every electrical circuit needs a ground (or a return path) to function. No the housing doesn't need to be grounded.

Cageman made a pretty strong negative statement about the competence of someone that suggested a coil needs to be grounded. He made no distinction between the electrical requirements of a coil to function and the mechanical construction, that makes him mostly wrong in my book when someone is trying to learn about his ignition system and fix a problem.

He meant the case, or the coil itself, Im pretty sure everyone knows an electrical circuit needs to have a ground or else it would be open. You could mount a coil on your windsheild and it will work as long as the two wires are hooked up and the coil wire will reach.
Hey why dont we really get technical and explain why a coil works, that is much needed info on this post too, then we will all drop our pants and see who is bigger to see who wins, that sound good?

[cageman]

Originally Posted by aarracer

Most early factory coil brackets have a threaded tang that a ground screw is threaded through and up hard against the coil body.

How early is that, I have never seen one, but I dont doubt it, naybe this is where the theory of grounding a coil came from, I dont doubt anything any more. These car companies have came up with some really good stuff through out the years, like drive by wire instead of a throttle cable, thats about as dumb.

[aarracer]

Cageman. It's on my 1970 six pack.

[dgc333]

A technical reason for grounding a metal coil housing is it acts a shield against electromagnetic interference (EMI). They quite often put a capacitor between the + terminal and ground to filter EMI that is conducted on the wires back into the wiring. The gound can of a coil will shield against EMI being radiated into the air.

I can remember as a kid an occasional car going by the house causing the TV to go crazy. Resistor wires and plugs along with capacitors and other shielding methods were instituted to keep the EMI created by the ignition and charging system from interfering with radio and TV broadcasting. The FCC has instituted regulations to prevent all kinds of products from causing TV and radio interference.