Misfire

[technician117]

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Hey guys. It seems pretty common that these engines are sensitive to spark plug condition and gap. I changed my plugs less than 2,000 miles ago with a new set of OEM Bosch plugs I got from Amazon. I set the gap at .028" because the car is bone stock and also that was the gap the "old" ones were set at from the dealer (under previous ownership).

Earlier this week I experienced my first misfire and limp mode (drivetrain malfunction). I had to clear the code with ISTA to get it to run right again. I took it out for a test drive and beat on it pretty hard a few times and nothing happened. Ran great. Fast forward 5-6 days and a couple hundred miles and it just happened again. All the same misfire related codes with the only specific one being for cylinder #5 in both cases. Other related codes included fuel shut off for that cylinder. I assume this is still spark related though? Possibly dying coil?

I also got code 800BAA = 1RSVC: CVBS output, open circuit or not connected. Anyone know what this means? EDIT - nevermind, I found a better description for the code. Seems like the forward camera is inop, or was. I'll diagnose this separately.

[allmotor_2000]

Swap that coil and see if the code follows..

[technician117]

Originally Posted by allmotor_2000

Swap that coil and see if the code follows..

Fair enough. That would be my natural progression unless the replies said "just replace the coil". I hate diagnosing by new parts unless there is no other easy way. In this case, there is an easy test.

I'll swap it from cyl #5 to cyl #1 on the other bank. Rather not do adjacent cylinders. Thanks for the reply.

[wheelpro]

Check gap for cyl 5 and others
Check ignition coil too

[technician117]

Tonight I swapped the coil and took it for a drive. First time I whomped on the throttle in Sport Plus, it set the limp mode. New code for Cylinder 1, so the code followed the coil. I already ordered 2 coils, 1 as I suspect here and 1 for a spare since they are so cheap!

[SapphireM5]

Originally Posted by technician117

Tonight I swapped the coil and took it for a drive. First time I whomped on the throttle in Sport Plus, it set the limp mode. New code for Cylinder 1, so the code followed the coil. I already ordered 2 coils, 1 as I suspect here and 1 for a spare since they are so cheap!

Good job, sounds like that's it! Nice easy fix!!

[BB6]

Originally Posted by technician117

Tonight I swapped the coil and took it for a drive. First time I whomped on the throttle in Sport Plus, it set the limp mode. New code for Cylinder 1, so the code followed the coil. I already ordered 2 coils, 1 as I suspect here and 1 for a spare since they are so cheap!

I chased the same thing for a while, but this was after I had the car tuned and downpipes. I normally work on my cars but had the guy who pulled my DME's to tune them change the plugs and gap them since he was already in a position for easy access. Long story short he fried my DME and I had to get a new one cloned, but even after I had a proper working DME I had DTML. I had misfires and found out that not only did he fry my DME, but he did not gap them to what I told him to and he probably over torqued them as well considering how sketchy of a guy he was in the first place. I also found out that a couple of the coils where not snapped completely down in locking position. I can tell you that the hinges of the coils actually get a little warm sometimes and warp so they don't lock down completely. So it ended up being a combination of things to remedy DTML: re-gap the plugs appropriately, make sure I had coils snapped completely down and they were not heated w/warped hinges, and make sure the plugs are torqued properly.
The longest trouble shooting I had to do was because of warped hinges on the coils. Car would run fine idling and low cruising, but when I got on it it felt like it dropped a cylinder and DTML. ISTA showed where it was happening so luckily I had backup coils and swapped them, the same issue happen. I swapped coils, plugs, chased for a long time. I finally found (after swapping the plug twice and two different coils on the cylinder having the misfires) the two coils I swapped in both had the same issue with the hinge not locking down properly, WHAT ARE THE ODDS!. Drove me nuts. So I prayed for my sanity (because I knew next was injectors) and swapped in the 3rd coil and I think I actually cried a little, perfect running car. Its actually is a love hate relationship with these cars.
Sorry for the long explanation but it was a pain trying to diagnose and hopefully this gives a little check list.
One other thing, I may be wrong, aren't the stock plugs gapped at .032. I could be wrong on that as I only gapped them to .019 after the tune and didn't check the stock gap.

[technician117]

Thanks for the reply. I replaced the coil on Wednesday night and so far so good. Your post is still good information for the future and for others to see.

The only saving grace with these plugs and coils being finicky is that the coils are cheap and plug gap can be adjusted as much as you want (unless the plug got fouled out badly). I bought OEM Bosch coils on RockAuto for just over $20 each. I contemplated just replacing them all but I hate replacing parts for no reason. Especially since the coils on my S62 are all original after 282,000 miles and 18 years of abuse! I did buy a 2nd one to keep as a spare for diagnostics, etc.