Swapping coils...

Hey, all.

I have an 02 WRX wagon, manual. 68,000 km.

A couple of days ago, the CEL came on - solid, then blinking, then solid. And the car was sluggish, moreso at low rpms.

I called the dealer, and had it towed, even though it was technically driveable - the flashing CEL had me spooked.

They pulled codes 301 and 303, which (according to workshop manuals I downloaded in PDF) mean misfire in cylinders 1 and 3.

They swapped coil 1 for 2, and 3 for 4 (I say that like I know what it means - and I really don't). The CEL went away, but the dealer said it could come back - the swap was partly to narrow down the problem - if I get CEL codes 302 and 304 now, they'll replace the hardware. The issue is not, according to them, engine-threatening, and they didn't recommend throwing hardware at the problem right away.

Now: I admit I'm an uneducated dork when it comes to auto mechanics. I want to understand where these coils actually are, what they do, and why they might go bad. And what does it mean when they go bad? Is it a 'wear' issue? Something electrical? Did they have to pull the heads to get at these things, or are they part of the ignition system?

I would have asked at the dealership, but everyone was busy and the gal that rung me in obviously knew nothing beyond what she read on the work order.

Again, I do have these workshop manuals, but they're more a recipe book for fixing stuff, where I am looking to understand how it all works.

Any suggestions of online resources?

Thanks,

BD

Reply to
BD
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Coils are those things on top of the manifold that the spark plug wires originate from. Coils produce the spark that fire the spark plugs. Dealer swapped positions to see if the problem moves to the other side of the engine. If the 2 cylinders that originally didn't show a misfire code now show a misfire code then the problem is probably that set of coils. But if you want to tinker yourself, replace the spark plug wires before anything else. Wires are cheap, coils aren't.

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Reply to
johninKY

Thanks. I'm not likely to tinker - I don't like to stick my hands somewhere where I don't really know what I'm doing. That said, I would like to understand what's going on.

Thanks!

Reply to
BD

Suggested replacing the spark plug wires because that has a good chance of fixing this problem. Subaru coils rarely fail. Also check the spark plug wells for oil. Oil down there will also throw this trouble code.

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Reply to
johninKY

At least OP has a workshop that believes in trying diagnostics & substitution

*before* throwing the customer's money at the problem! Nice to hear. Cheers

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Reply to
hippo

I think they pulled and inspected the plugs, so I'd figure they'd have cleaned up any oil that might have been in there.

I know my oil level was a bit lower than it should have been - not sure if that's a factor (you mention oil being where it shouldn't, so it did come to mind)

Thanks!

Reply to
BD

Yep, and so long as that approach doesn't impose undue risk in this case, I'm grateful.

Reply to
BD

Hi, When I had that problem, it was plug wire leaking. I could see firework in the dark. Sparks jumping all over.

Reply to
Tony Hwang

When my 2003 was around 100k kms, it started misfiring on one cylinder. They put silicone grease on the contact points between the coils and the wires, and that was the end of the problem. If your contact points were a little bad, the action of swapping the sides might be enough to solve your problem. At least for another few thousand kms!

Reply to
Chicobiker

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