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Dielectric grease, it is not a new idea, but putting it on my coils has had remarkably good results. A few months ago my wife's Turbo X was beginning to misfire again at full boost. I was out of new coils so I ordered three more. But before they arrived I decided to try some dielectric grease and see if it had any affect on the misfires. The theory being that the electrical spark is arcing across the coil and cylinder head, not the spark plug. The grease is an electrical insulator and can reduce undesired arcing. On my other high performance engine I had an arcing problem and there was evidence of pitting on the side of the coils from the arcing. But those coils were entirely plastic. The Saab V6 coils have a large metal sleeve on there side which does not leave evidence of arcing. At least none that I could see.

So I coated the outside of the coils as if I was a proctologist getting ready for work. Keep the grease away from the wire spring connection which contacts the top of the spark plug, but give the rest of the sleeve a good coating.

The dielectric grease has eliminated all but a few random misfires. My wife reports that it now misfires once or twice a month. Its not a complete fix, but I am hopping to get much longer life out of my coils now. I was going through at least 3 a year.




jmcdoogie posted some good info about coils and I wanted to include it here.

earlier this year I was having a problem with the missing under WOT (or at high boost) - and my coil packs only had 25,000 miles on them.

so after several phone calls, I finally got an Airtex Engineer on the phone
we talked about a few different subjects related to misfires (they make Coils for our Saabs)

we talked about some different coil-related things, but the gist of our discussion was based on his assertion that most ALL coil failures are heat related. He felt spark plug gap was typically your first culprit (with modern engines). He said that the ECU controls the spark voltage for the most part - BUT as the gap widens (or if its too big from the start) the amount of voltage must be increased dramatically to jump the gap, thus greater heat is produced. These coils have transistors in them, so they will begin intermittently failing, giving you a miss under high demand condition. Then eventually they'll fail altogether.

Or also if the gap is "too wide" and a higher voltage is required to jump the gap, there's not enough time at high RPM for the voltage to build up in the COILs secondary windings high enough to jump that gap. I guess we're talking a few extra milliseconds here or there, and suddenly no spark happens.

So whatever the problem, he recommended setting the spark plug gap a little narrower then OEM spec. And, since I have a "boosted" car (bigger Turbo, injectors, throttle body, Tune) in his opinion my gap should definitely be set narrower.

his opinion was the typical ECU can do it's job effectively (altering ignition parameters in real time) if the gap is a little narrower, but the ECU has limited recourses for a gap that's too wide.

Anyway, after that phone call, I pulled all my plugs and re-gapped them narrower, and haven't had a problem since - whether at WOT at high speed, or when nailing the throttle to the floor at low speed.

He also suggested making sure all connections are clean and solid. if there's any arcing between any connectors that will increase heat. And, if there are any grounds or faults that are causing voltage leaks that could also cause misfires. So he suggested looking at the whole length of the Coil boots for signs of arcing, and at the ends where it fits over the Plug. Make sure it fits solidly onto the Plug, and use some dielectric grease to keep contaminants (oil, water, dirt, beer) out of there.

Anyway, I hope you don't have a permanently damaged Coil - hopefully replacing the Plugs will help.

Here's the plugs I am using - I gapped them down from 1.14mm (0.045") to 0.85mm (0.034") - Pulstar be1i
Pulstar be1i Iridium Pulse Spark Plug,Pack of 1 : Amazon.com : Automotive

I think the Denso's that most people use come at 0.85mm (0.034") so maybe you'll have to go even narrower (0.65mm - 0.25" ?) if you use Denso or NGKs
 

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I've always used this and it's hasn't helped out my situation. Might work for others though!

I'm going back to NGKs and closing up the gap a bit in hopes it helps out. If not I guess a round a coils is going to be 30k regular maintenance on these.
 

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I've always said closing the gap will fix everybody's issues for years now, the grease is a good idea as well but i'm glad people are starting to understand that the gaps on these cars for oem spec is entirely too wide... its ridiculous for a turbocharged car.

When I go with a larger turbo, i'll be gapped down to .028 (oem is .040)
 

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Gap properly.

I've never NOT used dielectric grease when changing plugs/boots.

Its $0.50 for a little packet of it thats enough for at least 12 plugs.
 

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Knock on wood.... I've gone 85,000 miles on the original ignition coils with absolutely no problems whatsoever. Guess I should be ready for them to fail at any time, eh?
 

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I've got 130,000 on my car(my mistake of driving to Nashville to see my ex a couple times) and I've only replaced only the 3rd cylinder coil so far. I got the car in 08 with 50,000. JZW suggested that I run cooler plugs and I have for about 2 years now and I push my car alot. Haven't had a problem yet but I'm thinking of changing them all when I get the tune.
 

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I messed with the ignition so much when trying to nail the E85 tune down...Tried everything from playing with the gap, swapping coils, dielectric grease...lots more boost and the extra fuel with e85 would blow the spark out and misfire under higher boost, I'm running BCPR7ES gapped down to .028" at 25psi and it works great.

Extra stress on the stock coils from a tune (first tune right off the bat usually does it) causes them to fail pretty easily, but the upgraded coils with the black tops are stronger, and you shouldn't have an issue with the right plugs. I started using the dielectric grease on all 4 of my new ones, to help it conduct easier and hopefully lengthen their life.

But if the gap is bigger than it needs to be, it might be what wears the coils out quicker, as a bigger gap requires more voltage for a spark...I wonder if that's why they die so often. Stock gap was 1.0mm, I ran .9 for that and my stage 1 tune.
 

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For sure all these coil issues are heat related, when they say the 2.8 liter engine bay is cramped it is very cramp.

The 9-4x 2.8 Liter with acres of room inside the engine bay has no signs of coil issues, maybe we need the coil packs with heat sinks on them or something along the lines of that
 

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I removed the heat barrier on the hood, forgot what it's called.. the engine cover, plastic under shields, moved the battery out of the engine bay, big FMIC and a few other pointless plastic pieces in the bay like the plumbing behind the grille and it breaths alot better, doesn't get nearly as hot and I don't get any coil issues running JZW stage 5. A ventilated hood would help even further to get rid of high bay temps.
 

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I removed the heat barrier on the hood, forgot what it's called.. the engine cover, plastic under shields, moved the battery out of the engine bay, big FMIC and a few other pointless plastic pieces in the bay like the plumbing behind the grille and it breaths alot better, doesn't get nearly as hot and I don't get any coil issues running JZW stage 5. A ventilated hood would help even further to get rid of high bay temps.
I should remove the engine cover at least I guess... Still having issues with mine. Blargh :(

That'd be sweet to have a ventilated hood ;ol;
 

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I removed the heat barrier on the hood, forgot what it's called.. the engine cover, plastic under shields, moved the battery out of the engine bay, big FMIC and a few other pointless plastic pieces in the bay like the plumbing behind the grille and it breaths alot better, doesn't get nearly as hot and I don't get any coil issues running JZW stage 5. A ventilated hood would help even further to get rid of high bay temps.
Agreed, except have left my hood liner on as a Saab tech guy pointed me to all the old saabs with white spots on the bonnets directly above where the turbo sits.

I have a custom mesh grille to get more airflow into the engine bay. Heard various reasons why sides grilles are blocked std but been running with them open and no issues so far. Also going with a catless DP removes a major source of under bonnet heat.

I no longer have the heat haze rising off my bonnet at stop lights that concerned me greatly when I got the car.
 
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