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Old 12-03-2012, 11:26 AM   #1
CptJoe
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Default Bad coil packs?

So ive searched all over and think Ive found the solution to my problem but my question is, is there a way to determine which coil pack is bad without the car throwing a code?

I have a stage 3 wrx with vf39, full ebay exhaust, walbro 255, sti pinks, act hd - ss, sti tmic, k&n short ram.

The problem was real bad at first, usually at open throttle it will stutter really bad once I start hitting boost around 3.5, 4k. I had the plugs changed and it made it alot better but it still stutters around 4 - 5k. The cars still making max 18 psi so I ruled out the turbo going bad but my question is can you determine which coil pack is bad? Should I change them all out? and is this a job I can do on my own? I read other threads and it says its a 10 min job.
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Old 12-03-2012, 11:44 AM   #2
HonduhPowa
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Are you sure it's not the tuned...is it even tuned? (I would assume so but just asking)
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Old 12-03-2012, 11:46 AM   #3
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Sorry if I left that out, yea it has an open source tune. Also Perrin inlet hose, tgv delete, turbo smart boost controller. I think that's most of the crucial information.
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Old 12-03-2012, 11:54 AM   #4
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But nah its def not the tune, been running on it for months.
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Old 12-03-2012, 12:14 PM   #5
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If there are any clips broke on the packs your harness will loosen and your car will misfire. Use tiewraps to secure the harness.
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Old 12-03-2012, 01:36 PM   #6
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Quote:
Originally Posted by zmi View Post
If there are any clips broke on the packs your harness will loosen and your car will misfire. Use tiewraps to secure the harness.
I doubt it i had my tuner change out the plugs while I was at work and they said it was fine but as soon as I got on it, it still made the same hesitation just not as bad. They said it might be bad gas but I filled it w 93 and ran through it 3 times. I think I just have one bad coil, hence my questions in the first post.
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Old 12-03-2012, 06:36 PM   #7
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try replacing the fuel filter...
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Old 12-03-2012, 07:13 PM   #8
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try replacing the fuel filter...
that's also on my list. have any of you guys changed out the coil packs? it seems simple enough it just NEVER goes the way you want, and is there anything you can faq up besides breaking the clip that holds it in? im a little apprehensive when it comes to something ive never done.
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Old 12-03-2012, 09:49 PM   #9
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Do to the fuel filter first. Unless you have a code, it probably isn't the coil packs.

Double check your tune for misfires.

I replaced the coil packs on my bugeye, but I was getting a misfire code, and the code followed the coil when I swapped them around.

If you have the right tools, changing them isn't hard, but you might as well do the plugs too for all the time it will take you (removing the airbox, battery, windshield washer tank).

Be very careful not to overtighten, and make sure the bracket on the back passenger side coil is properly in place (it is a ground as well as a bracket for the 02 wire).
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Old 12-03-2012, 10:50 PM   #10
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Quote:
Originally Posted by ezil71 View Post
Do to the fuel filter first. Unless you have a code, it probably isn't the coil packs.

Double check your tune for misfires.

I replaced the coil packs on my bugeye, but I was getting a misfire code, and the code followed the coil when I swapped them around.

If you have the right tools, changing them isn't hard, but you might as well do the plugs too for all the time it will take you (removing the airbox, battery, windshield washer tank).

Be very careful not to overtighten, and make sure the bracket on the back passenger side coil is properly in place (it is a ground as well as a bracket for the 02 wire).
The only reason I think it's the coil packs because I went through some gnarly puddles during hurricane sandy and maybe that finally rusted them or something. But the fuel filter is a cheap fix so I don't really mind doing that. It's just seems like $&@t keeps breaking and I don't even wanna think about it being tune related, that starts at 250$ and I just spent 300$ for new plugs and a leak down test. It just seems when I finally get ahead and want to do an exterior mod this crap happens. (End rant)
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Old 12-03-2012, 10:53 PM   #11
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Look close at each coil pack for one that looks melted or has some bulging compared to the others. Sometimes that can tip you off to which one is bad.

Another thing to check is that your plugs are properly gapped. I had that problem on my car when I was in a hurry changing plugs one day and forgot to gap them properly. 4K rpm it started missing. Regapped them and it was good as new.
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Old 12-03-2012, 10:58 PM   #12
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Originally Posted by speedyHAM View Post
Look close at each coil pack for one that looks melted or has some bulging compared to the others. Sometimes that can tip you off to which one is bad.

Another thing to check is that your plugs are properly gapped. I had that problem on my car when I was in a hurry changing plugs one day and forgot to gap them properly. 4K rpm it started missing. Regapped them and it was good as new.
Like I said I had a very well known shop change them and I'm fully confident they did the work right. I'm going to check them out when I get a chance. But I think it's a coil or a fuel filter, any chance a fuel filter can get knocked loose? The day before it started happening I got on it real hard in 1st and bounced off of redline.
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Old 12-04-2012, 09:34 PM   #13
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rotate the pack to another cylinder if misfire codes follows you on to something!
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Old 12-22-2012, 06:19 PM   #14
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I am having the same EXACT problem. I changed my plugs today and it kinda went away but it's still slightly there I will be checking my fuel filter tomorrow and I'll relay my results. It's been some time now so if you did find the problem could you please update or pm me. Thanks
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Old 12-22-2012, 07:03 PM   #15
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You have to inspect these things super closely, I had a hairline crack no longer than 2mm coming from the edge for #4 and was causing misfires under load and threw a cel. Swapped out a new one and it's perfect. I'd look over yours very closely, anywhere losing spark is weakness.
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Old 12-22-2012, 10:46 PM   #16
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Quote:
Originally Posted by Lima05 View Post
I am having the same EXACT problem. I changed my plugs today and it kinda went away but it's still slightly there I will be checking my fuel filter tomorrow and I'll relay my results. It's been some time now so if you did find the problem could you please update or pm me. Thanks
Hey I changed out the coil packs and it runs fine, don't worry about your fuel filter it should last you the duration of time that you own the car. I went ahead and replaced all 4 because my tuner said he wouldn't charge me labor, ran me about 370.00$ for 4 coils w no labor. Oem from a subaru dealership.
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Old 12-22-2012, 11:03 PM   #17
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Quote:
Originally Posted by CptJoe View Post
Hey I changed out the coil packs and it runs fine, don't worry about your fuel filter it should last you the duration of time that you own the car. I went ahead and replaced all 4 because my tuner said he wouldn't charge me labor, ran me about 370.00$ for 4 coils w no labor. Oem from a subaru dealership.
Your kidding right....?


There is an interval for changing the fuel filter, just like there is for engine oil, spark plugs, pcv etc. It gets plugged with dirt and crap that builds up in your tank. We all know what happens with you plug up a filter that has fuel flowing through it... decreased flow.
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Old 12-22-2012, 11:06 PM   #18
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Originally Posted by TwoFifty View Post

Your kidding right....?

There is an interval for changing the fuel filter, just like there is for engine oil, spark plugs, pcv etc. It gets plugged with dirt and crap that builds up in your tank. We all know what happens with you plug up a filter that has fuel flowing through it... decreased flow.
Just relaying the information my tuner told me. He said on the 04 there usually good for a long period.
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Old 12-22-2012, 11:11 PM   #19
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Quote:
Originally Posted by CptJoe View Post
Just relaying the information my tuner told me. He said on the 04 there usually good for a long period.
It may well not actually be plugged when you replace it, but that is why it's called preventative maintenance.
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Old 12-22-2012, 11:18 PM   #20
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It may well not actually be plugged when you replace it, but that is why it's called preventative maintenance.
Yea I'm not one of those uptight subaru owners that freaks if I'm at 3,001 miles over a synthetic oil change. Il get any problem fixed immediately but if it isn't broken I'm not spending money on buying new parts. To each his own.
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Old 12-22-2012, 11:23 PM   #21
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Quote:
Originally Posted by CptJoe View Post
Yea I'm not one of those uptight subaru owners that freaks if I'm at 3,001 miles over a synthetic oil change. Il get any problem fixed immediately but if it isn't broken I'm not spending money on buying new parts. To each his own.
Oh don't get me wrong i'm not one of those guys either. But fuel is important and I've seen the outcome of severely plugged fuel filters.
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Old 12-22-2012, 11:29 PM   #22
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Oh don't get me wrong i'm not one of those guys either. But fuel is important and I've seen the outcome of severely plugged fuel filters.
Honestly my cars in and out of the shop at least twice a month getting stuff done and I just had a fuel pump put in so I'm pretty confident everything's running as should, but your def right it is a key component if it does get clogged but i rarely ever hear of it cus of the detergents In 93 oct, usually keeps them mint for a while.
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Old 12-23-2012, 09:46 AM   #23
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Thanks for the update.

Yah I put in a new walbro 255 about 6 months ago before I had my tune, I've read/heard some occasional problems with their filters. I just figure since I have the oem filter laying around I'll try it just so I don't have to spend the $$ on the coils but if it has to be done then so be it.
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Old 12-23-2012, 12:30 PM   #24
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Quote:
Originally Posted by Lima05 View Post
Thanks for the update.

Yah I put in a new walbro 255 about 6 months ago before I had my tune, I've read/heard some occasional problems with their filters. I just figure since I have the oem filter laying around I'll try it just so I don't have to spend the $$ on the coils but if it has to be done then so be it.
If your throwing a code you can switch them around to find which is causing the misfire then just replace the 1 coil. Usually it's just one that goes bad, in my case I wasn't throwing a code so I had to replace all 4.
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Old 12-23-2012, 03:44 PM   #25
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Yah mine is throwing no codes. Kinda fudged. I'm looking into coils at this moment seems to be the problem.
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