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Discussion Starter #1 (Edited)
No start - IGN Coil fuse blown

Okay - got a frantic call from my wife last night. She was stuck on a freeway off ramp (thankfully near home) after driving 60 miles prior. She had called me earlier in her trip saying the van was acting funny like a vibration/hesitation and the CEL would occasionally flash. I told her to keep driving to get it home.

Apparently, once she stopped at the end of the off ramp, the van died and she called me from there. I rushed over to find the interior lights a bit dim and a strange smell from the engine compartment (not a burnt oil, rubber or trans fluid smell, but perhaps electronics - don't know). I tried starting it, the engine turned over slowly and would not start. Thankfully, a neighbor happened by and towed us back home - not far.

I pulled the battery out this morning and hooked it up to a charger. Tonight, after work, I reinstalled it and cranked the engine over - no fire/start again but it did turn over normally. Earlier, I thought maybe the alternator went bad and she was driving for a while under battery power only - draining the battery - but that wouldn't explain the odd "burning" smell.

I then checked fuses and found the 15A ignition coil fuse by the driver's door (under the dash) was blown. Replaced it and it blew when I tried to start it again.

I pulled the connectors off each ignition coil and checked coil resistances. All coils read about 500 ohms one way and 1700 ohms the other way (switching polarity of my meter leads). So I figure it's not the coils...

I searched this forum for like symptoms and didn't have any luck.

Any suggestions???

Thanks!
 

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There's not much to that circut. It feeds the 15A directly to all the igntion coils pin 3's. (the wire is black with a yellow stripe)

Try pulling all the coil wires off and trying it again.


Pretty much if it isn't a bad coil, you need to start searching for a short to ground of the black/yellow wire.
 

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I'll go so far as to assume its a bad coil. There just isn't much likelyhood the wiring has gone bad.

My bet is that the coil behaves normally until the ICM calls for a spark, and then the coil draws too much current.

Its easy to check... bring lots of spare fuses!

First, try no coils connected. If the fuse doesn't blow when the ignition switch turns On, the wires are fine.

Try connecting all the coils, but don't crank the engine, turn it to on then off, then check the fuse. If the fuse hasn't blown, then its a spark-request induced failure.

Disconnect all but one coil, then crank the engine a few revolutions. you really only need two revolutions to get a spark request for every cylinder, and you are pumping unburned fuel into the exhaust system, so don't crank more than you need to.

If you want to, leave a whole bank of coils connected, and see if the fuse blows when you crank it. That'll cost you a fuse, but decrease the search count by several coils.

In all likelyhood, you'll find one bad coil.
 

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Discussion Starter #4
Toasted Coil

Thanks for the response.

Well, you were absolutely correct, SuperDad. I did a little more searching on anything related to these ignition coils and ran across a thread about someone's middle front spark plug backing out and frying the coil, causing the IGN COIL fuse to blow and a no start condition.

So tonight, I checked my middle front coil and sure enough, it fell apart as I pulled it out. Nicely toasted to charred metal shrapnel and bare coil wire. I couldn't believe it, but it certainly explained it's behavior.

I looked down the spark plug hole and saw a charred mess. Tried to loosen and back out what was left of the spark plug, but it wouldn't budge, mainly because I couldn't get the socket around the hex part of the plug. The plug was surrounded with charred junk and was pointing off to the right also, not straight in the hole.

The van was in the street in front of our house and I wanted to get it in our drive way since it was obvious now this would not be a quick fix. So I hooked up the remaining coils, put in a new fuse and started her up. She made a bang at first then ran on five with the sixth puffing every cycle. I was able to back up and pull her into our driveway (a little uphill) and shut her down. Found the charred spark plug in the street where it was parked, so it must have been ejected, causing the bang I heard at first.

The diagnosis thus far is that the majority of the threads in the head's spark plug hole are basically missing except for about three or four closest to the combustion chamber. The charred plug tells an amazing story of a blowtorch cutting through all the threads down a single line and past the seat. Really interesting.

So now I need to get in there and install a heli-coil in the head and replace the plug and coil. If you have any ideas on how to heli-coil this, I'm all ears since the threads, as you know, are WAY down in the head. Do I need to pull the head to fix it? I've read of others not needing to do that. Just that access is extemely limited there, with the metal tube surrounding the hole not helping things either... Wish me luck! I'm still shell shocked about this. Such a thing has never happened to me, and I've wrenched on a lot of cars in my day...
 

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You may be able to heli-coil it even with the limited access. The folks at heli-coil know the needs of their customers, and may have created a set just for this repair. I know they did that for some domestic trucks that were known to toss their plugs regularly.


You might want to check with a Honda dealer. They probably know about this repair.


Even with a standard heli-coil repair kit, with a bit of ingenuity you should be able to use it. Its been quite some time since I've used one, but if it acts like a standard tap with a square drive, you can use a 12 pt socket to drive it. In fact, because its so far down, it will be very easy to keep it centered.

Yes, pulling the head would result in the best repair.

I know its obvious, but be sure to have the piston well below TDC before helicoiling. Also, whatever you stick down there to cut metal, coat it well with heavy wheel-bearing grease to catch the cuttings.
 

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What is the history of this van? A probable cause is improper installation of spark plug i.e. was not tightened properly and came loose. Something like that will happen within few hundreds (or couple thousand) miles of the plugs installation and NOT after years of running without any problems.

I recall there was at least another incident of charred coil reported in this forum

- Vikas
 

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Re: Toasted Coil

2000GoldenOdy said:

I pulled the connectors off each ignition coil and checked coil resistances. All coils read about 500 ohms one way and 1700 ohms the other way (switching polarity of my meter leads). So I figure it's not the coils...

...
...

So tonight, I checked my middle front coil and sure enough, it fell apart as I pulled it out. Nicely toasted to charred metal shrapnel and bare coil wire. I couldn't believe it, but it certainly explained it's behavior.

...
...
Are you saying that the coil was fine when you checked it first time after encountering this problem but fell apart later???

- Vikas
 

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Discussion Starter #8
Time-Sert

Ok, a few days has passed and I'm in the middle of repairing the spark plug hole.

BTW, I had changed plugs maybe two years ago. The engine ran fine up to now (although we did have our trans replaced again since). I'm pretty thorough when I button things up, so I would hope I didn't leave this plug loose, but you never know. Interesting that another post in a thread here mentioned that when this happens, it's usually the front middle plug - which is true for my case also.

Regardless of it's cause, I need to fix it obviously. So I ordered a Time-Sert kit (extended length version) and have started in on using it. I've tapped the hole with no problem. However, I found that the seat cutting tool appears to be contacting the steel tube at the bottom of the spark plug/coil cavity and that has me worried that I will cut through it. It appears the that inner blades of the cutter are not contacting the aluminum at all to cut the relief for the top of the insert that needs to go in to make the fix. I'm using plenty of grease around the cutter (and tap) to catch the shavings, which also conveniently shows me which blades are cutting and which are not. The inner blades are obviously not cutting (yet).

I sent an email out to the Time-Sert folks about this. I'm not familiar with the steel tube - whether the spark plug washer seats against it or what "leak" may occur (like to the volume under the valve cover) if I do cut through it. I don't have a boroscope, so can't judge if cutting though it is detrimental.

So, I guess I'm waiting on further direction from Time-Sert. I also PM'd someone on this forum (The Farmer) who posted that he fixed a spark plug hole with a Time-Sert, so we'll see...
 

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Discussion Starter #9
Re: Re: Toasted Coil

sontakke said:
Are you saying that the coil was fine when you checked it first time after encountering this problem but fell apart later???

- Vikas
No, I should have said that my initial resistance check didn't tell the full story. From the terminals I checked, the bad coil read the same as the others. I'll chalk that up to operator error at this point. It wasn't until I read the post about the middle front coil usually being the culprit that I unbolted it and found it melted.
 
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