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I said biiiiiiiitch.....
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Discussion Starter · #1 ·
I was riding my bike to work this morning and about 1km down the road, at the bottom of a hill I noticed it sounded very different than it usually does. Almost like a twin instead of an i4. I also noticed after that it seemed to have a lack of power, and there were small surges as if one or more of the cylinders was only firing very rarely. From what I remember, there was no engine light or fault code, but I could be wrong. I'll have to double check tonight.

I turned back for home and took the subway to work instead. I hoping to pull it apart sometime before the end of the week and see if I can figure out what's going on. My guess is one of the cylinders isn't firing. I'm going to spray some water on the headers and see if I can identify if one of them is the problem.

If that's right, I'm going to start by investigating the spark plug and coils to check that their resistance is still in spec, there is a good connection, and they look like they should. My guess is that it could be a bad coil since a lot of guys seem to have problems with them.

Is there anything else I should start with? I'd like to take the next few days to read over some specific sections of the service manual and get prepared for whatever work I need to do when I get time for it.
 

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380 Posts
chances are bad coil, check resistances in the coil packs like you have said, and replace the faulty one. shouldn't bee too bad.
 

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I have had this a happen twice in the last few months. Did you ever figure out what it was? Mine would start back up after a session and act normal again.
 

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I said biiiiiiiitch.....
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528 Posts
Discussion Starter · #4 · (Edited)
Nothing yet. Pulled the coils tonight and they all seem fine. The results of resistance check 1 are reading a little high, but they're all the same so I'm pretty sure its my cheap multimeter. Im going to pull the plugs, hopefully tomorrow. They have less than 10k kms though, so I expect they're all fine. If that's the case I'll put everything back together (with some dielectric grease this time) and hope it was just a bad connection somewhere.
 

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I said biiiiiiiitch.....
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528 Posts
Discussion Starter · #5 ·
I think I've got this fixed. Since the coils seemed fine I pulled the plugs. They looked normal except for a bit of a brown surface on the electrical connection which easily rubbed off. I'm guessing very light rust from moisture? I checked the gaps and they were a bit wider than spec so I regapped them. I put it all back together and it seems to be running normally again. I've only had it around the block though, need to go for a good ride this weekend.
 

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A quick way to find at least what cylinder it is, its to use a laser temp gun. The cylinder that isnt working right, will read a lower temp. After u find that exchange the coil from the bad cylinder with a good one. If the temp reads lower on the other cylinder now you have found your problem. A bad coil
 

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I said biiiiiiiitch.....
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528 Posts
Discussion Starter · #7 ·
Went for a good ride yesterday, and in to work this morning. Running well again. Might be a little rough on idle, but that could also be my imagination.

Over the winter I'm going to rip it apart again, recheck all the gaps, and clean the plugs a bit better. I was in a rush to get it running again.
 
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