heavy misfire-whats on my plugs?

Dhillon92 · 02-20-2015, 06:38 PM

Hey, I've run into an issue with my 6mt e92 n55xi. I was on the highway to Niagara the other day cruising in 6th gear and decided to floor it, now usually this happens, it sputters for the first thousand rpm, sorta feels like the tiresate slipping, but they aren't. Anyhow, I know its a dumb thing to do while it sputters, but I did it anyway.

When I got to about 4000 rpm the misfire got worst and jerked the whole car in all rpms and all gears. Got limp, pulled over, restarted car, finished my drive with a lot of ease on the pedal. It would stop misfiring if I'm very light on it.

Trip ends, drive back same way, call up dealer to tow it, uninstall intake and tune. As I was deleting the codes I saw what had come up, was a misfire in cyl 4 and fuel control mixture code. (29e0) Problem still persisted and was misfiring constantly.

Also had changed spark plugs about 2000 kms ago, they were Bosch but not BMW branded ones, so I figured I'd swap the old ones back in as well. Turned out, the misfire is now gone with the old 50km plugs back in, but I still feel a misfire every now and again at idle.

While I swapped em all out, I saw some gunk in the plug chamber and *sorta* wet carbonish stuff on the plugs.

I've searched and have figured it is either coil or injectors, because I feel like if I put my jb4 back in and push it, I can replicate the problem, I just can't replicate it while car is stock, and am not sure what to present the dealer with now.

Attached are pics of the gunk in my chambers, what is that stuff?

Thanks for the feedback!

weehe126 · 02-20-2015, 10:39 PM

Looks like a leaky valve cover gasket. Which in turn fouled up your new spark plug.

hailpersia · 02-21-2015, 02:41 AM

odd, I started experiencing the same thing on Cobb after the VANOS recall. no codes and only on Cobb. going to change plugs this weekend.

Dhillon92 · 02-21-2015, 04:16 PM

Interesting, I have also found oil sprayed onto my intake pipe and near my coolant tank. Might very well be a VCG!

weehe126 · 02-21-2015, 09:46 PM

Quote:

Originally Posted by Dhillon92

Interesting, I have also found oil sprayed onto my intake pipe and near my coolant tank. Might very well be a VCG!

That is probably from the oil filter housing gasket/oil cooler gasket. Looks like you have a few gaskets to change lol.

sy2767 · 02-22-2015, 10:14 AM

Quote:

Originally Posted by weehe126

Looks like a leaky valve cover gasket. Which in turn fouled up your new spark plug.

How is that possible? LOL. Do you realize it's impossible for a leaking valve cover to foul a plug? Not trying to be rude just stating the truth. I would also like to add that the spark plug looks ok to me, I don't see a cause of the misfire by looking at that picture. The "gunk" in the pic is just a little seepage of oil from the valve cover gasket, I would put some spary 9 or other grease-oil cleaner on a rag and clean it off, check it again in a few weeks to see if it returns. I certainly wouldn't replace the gasket if thats all it's seeping.

Chocolatethunder · 02-22-2015, 12:05 PM

If you have bad injectors, possibly 1 stuck open this would definitely cause your spark plugs to be gunky. You can check and see if you smell gas coming out of your exhaust pipes. But injectors cost more but if you are running a JB it will exploit your fuel system and find weak points so you will eventually need to do coils as well as wallnut blast. This combo will have your car running smoothly.

Dhillon92 · 02-23-2015, 03:12 PM

Thanks for all the feedback guys! Cars going into dealer tomorrow I'm going to point these things out to them and let's see what they replace. Will keep thread updated!

weehe126 · 02-23-2015, 06:09 PM

Quote:

Originally Posted by Chocolatethunder

If you have bad injectors, possibly 1 stuck open this would definitely cause your spark plugs to be gunky. You can check and see if you smell gas coming out of your exhaust pipes. But injectors cost more but if you are running a JB it will exploit your fuel system and find weak points so you will eventually need to do coils as well as wallnut blast. This combo will have your car running smoothly.

If he had an N54...

Dhillon92 · 02-25-2015, 03:19 PM

So BMW got back to me, replaced an oil line leaking, couldn't replicate my misfire since most of it is gone after switching back to stock plugs... Considering the jb4 isn't in they wouldn't be able to push it beyond stock limits anyway. So for now I'll just leave my stock plugs in, mod it back up, install my new catless downpipe and say goodbye to the dealer for a while!

On a side note: I got a 328d 2015 as a loaner with 9km on the clock, not bad!

02-20-2015, 06:38 PM	#1
Dhillon92 Captain 82 Rep 604 Posts Drives: '11 335xi Join Date: Jul 2014 Location: Toronto iTrader: (0)	heavy misfire-whats on my plugs? Hey, I've run into an issue with my 6mt e92 n55xi. I was on the highway to Niagara the other day cruising in 6th gear and decided to floor it, now usually this happens, it sputters for the first thousand rpm, sorta feels like the tiresate slipping, but they aren't. Anyhow, I know its a dumb thing to do while it sputters, but I did it anyway. When I got to about 4000 rpm the misfire got worst and jerked the whole car in all rpms and all gears. Got limp, pulled over, restarted car, finished my drive with a lot of ease on the pedal. It would stop misfiring if I'm very light on it. Trip ends, drive back same way, call up dealer to tow it, uninstall intake and tune. As I was deleting the codes I saw what had come up, was a misfire in cyl 4 and fuel control mixture code. (29e0) Problem still persisted and was misfiring constantly. Also had changed spark plugs about 2000 kms ago, they were Bosch but not BMW branded ones, so I figured I'd swap the old ones back in as well. Turned out, the misfire is now gone with the old 50km plugs back in, but I still feel a misfire every now and again at idle. While I swapped em all out, I saw some gunk in the plug chamber and sorta wet carbonish stuff on the plugs. I've searched and have figured it is either coil or injectors, because I feel like if I put my jb4 back in and push it, I can replicate the problem, I just can't replicate it while car is stock, and am not sure what to present the dealer with now. Attached are pics of the gunk in my chambers, what is that stuff? Thanks for the feedback! Attached Images
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02-20-2015, 10:39 PM	#2
weehe126 Brigadier General 1161 Rep 3,189 Posts Drives: 2017 340i Join Date: Apr 2014 Location: San Antonio iTrader: (2)	Looks like a leaky valve cover gasket. Which in turn fouled up your new spark plug.
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02-21-2015, 02:41 AM	#3
hailpersia Lieutenant 72 Rep 436 Posts Drives: 2022 Join Date: Nov 2012 Location: Bay Area iTrader: (5)	odd, I started experiencing the same thing on Cobb after the VANOS recall. no codes and only on Cobb. going to change plugs this weekend.
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02-21-2015, 04:16 PM	#4
Dhillon92 Captain 82 Rep 604 Posts Drives: '11 335xi Join Date: Jul 2014 Location: Toronto iTrader: (0)	Interesting, I have also found oil sprayed onto my intake pipe and near my coolant tank. Might very well be a VCG!
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02-22-2015, 12:05 PM	#7
Chocolatethunder Second Lieutenant 34 Rep 260 Posts Drives: E92 335i Join Date: Apr 2014 Location: BROOKLYN iTrader: (7)	If you have bad injectors, possibly 1 stuck open this would definitely cause your spark plugs to be gunky. You can check and see if you smell gas coming out of your exhaust pipes. But injectors cost more but if you are running a JB it will exploit your fuel system and find weak points so you will eventually need to do coils as well as wallnut blast. This combo will have your car running smoothly.
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02-23-2015, 03:12 PM	#8
Dhillon92 Captain 82 Rep 604 Posts Drives: '11 335xi Join Date: Jul 2014 Location: Toronto iTrader: (0)	Thanks for all the feedback guys! Cars going into dealer tomorrow I'm going to point these things out to them and let's see what they replace. Will keep thread updated!
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02-25-2015, 03:19 PM	#10
Dhillon92 Captain 82 Rep 604 Posts Drives: '11 335xi Join Date: Jul 2014 Location: Toronto iTrader: (0)	So BMW got back to me, replaced an oil line leaking, couldn't replicate my misfire since most of it is gone after switching back to stock plugs... Considering the jb4 isn't in they wouldn't be able to push it beyond stock limits anyway. So for now I'll just leave my stock plugs in, mod it back up, install my new catless downpipe and say goodbye to the dealer for a while! On a side note: I got a 328d 2015 as a loaner with 9km on the clock, not bad!
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