[jayess82]

Alright, a couple months back my e92 started missing pretty badly, so I parked it. I had codes for cylinder 6 and 4 misfires, along with multiple misfires. I ended up changing coils and plugs. The misfire stayed but only in cylinder 6. Tried swapping cylinder 6 coil around but misfire stayed at 6. I ended up replacing plugs again, but no change. Next thing was changing #6 injector. No change.

I've now got 29D2 (cyl. 6) and 29E1 (Mixture control 2). Can't remember if the last one popped up before or after changing injector. Did a compression test today and from 1 to 6 I had 190-210-210-205-185-0. This was done with a cold engine. I also did the cheap glove/cigar smoke test but didn't see any leaks. Trying to figure out what next step I should take before tearing it down. Recommendations? Didn't run hot, didn't get low on oil. Had no issues until it started missing.

[chris55552]

This may be irrelevant but I recently had a n55 with a misfire, took it to the shop and come to find out I lost cylinder compression in one of my cylinders, they scoped it and the cylinder wall was scarred from something coming loose and it was a death sentence for that engine. Hopefully your not in the same boat but it may help to scope it and visually inspect it. At only 40k miles too....needed an engine replacement. Luckily I raised enough hell and the dealership and BMW of NA stepped in and assisted. Very fortunate for that. Best of luck, hope everything turns out okay.

[gunnerxq]

Weird I'm wondering if the same thing happened to mine. Cylinder 6 misfire Code 29D2. How many miles on your engine?

I wonder if an ugly hidden issue is rearing it's head with these engines. You either make it or break it.

I have 184k miles. Had the car since 58k. Getting it compression tested Monday

[gunnerxq]

Maybe we just have broken valve springs like in this post? https://www.e90post.com/forums/showthread.php?t=1573305

[chris55552]

Originally Posted by gunnerxq

Weird I'm wondering if the same thing happened to mine. Cylinder 6 misfire Code 29D2. How many miles on your engine?

I wonder if an ugly hidden issue is rearing it's head with these engines. You either make it or break it.

I have 184k miles. Had the car since 58k. Getting it compression tested Monday

It happened to mine at 44k miles, 2 months after purchasing it. Talk about luck, absoloutely no warnig. I will say this though... and it could have caused it. I over used liqui molly anti friction mos2 and ceratec... used too much at too close of an interval. It was an x3 with the n55, and even after the new motor was put in i drove it for a while and literally got rid of it 2 weeks ago. Just wasnt happy with it, it had the base suspension which I didnt like, and I just didnt like the N55 near as much as the N52. It had alot of brute power at 306hp, but to me BMWs are about more than just straigh line performance, Their about balance, handling and Id take a better handling slower car any day over straight line performance. Where I live you can never tap into that power without getting ticket after ticket, so i got rid of it and now my second car is my daily driver, a e90 328i xdrive with a manual transmission. The x3 was just one issue after the other, my transfer case was making a noise and im certain it was on its way out which would have costed alot of money. Back to the liqui moly products. I love ceratec it makes an engine run smoother and quieter but you have to follow the recommended intervals of use which I neglected to do. Lesson learned.

[chris55552]

Originally Posted by gunnerxq

Maybe we just have broken valve springs like in this post? https://www.e90post.com/forums/showthread.php?t=1573305

ask them to scope it and look in there and see if there is cylinder wall damage. Thats how mine was confirmed bad.

[chris55552]

Originally Posted by gunnerxq

Weird I'm wondering if the same thing happened to mine. Cylinder 6 misfire Code 29D2. How many miles on your engine?

I wonder if an ugly hidden issue is rearing it's head with these engines. You either make it or break it.

I have 184k miles. Had the car since 58k. Getting it compression tested Monday

Oh man just a perfect person to ask.... How do you like your koni suspension. Thinking of buying it for mine and have heard good things. Im limited with an xdrive model but I hear Koni can improve some aspects.

[gunnerxq]

Originally Posted by chris55552

Oh man just a perfect person to ask.... How do you like your koni suspension. Thinking of buying it for mine and have heard good things. Im limited with an xdrive model but I hear Koni can improve some aspects.

Oh I love them. Wrote about them here post #34. Maybe I'd go with BMW performance springs this time around 48% stiffer than standard springs and 34% stiffer compared to sport springs. Maybe
https://www.e90post.com/forums/showt...6#post29946886

[chris55552]

Originally Posted by gunnerxq

Oh I love them. Wrote about them here post #34. Maybe I'd go with BMW performance springs this time around 48% stiffer than standard springs and 34% stiffer compared to sport springs. Maybe
https://www.e90post.com/forums/showt...6#post29946886

WOW, talk about an awesome ride. Looking at your suspension upgrades you have listed it has to be phenomenal and razor sharp in terms of steering. I cant imagine what benefits the m3 components bring to our generation of 3 series, Ive never driven an m3 and its probably better I dont, but damn those things are just so dialed in in terms of steering, suspension and driver focus. Test driving one like an e46 m3 would rip my heart out having to leave without owning it. I think thats what im going to go with. I reached out to strutmonkey with coilover recommendations and they actually suggested the konis with the eibach springs just like yours so im convinced thats a winning formula. If only I had known before buying my e90 coupe the limitations imposed by having the xdrive system, but the beauty of these forums is so many enthusiast, many with intelligent minds and passion for bmw's and driving have come up with ways to circumvent the xdrive and still upgrade them to a certain extent. I appreciate the feedback you provided, im excited and looking forward to getting them now

[gunnerxq]

Originally Posted by chris55552

WOW, talk about an awesome ride. Looking at your suspension upgrades you have listed it has to be phenomenal and razor sharp in terms of steering. I cant imagine what benefits the m3 components bring to our generation of 3 series, Ive never driven an m3 and its probably better I dont, but damn those things are just so dialed in in terms of steering, suspension and driver focus. Test driving one like an e46 m3 would rip my heart out having to leave without owning it. I think thats what im going to go with. I reached out to strutmonkey with coilover recommendations and they actually suggested the konis with the eibach springs just like yours so im convinced thats a winning formula. If only I had known before buying my e90 coupe the limitations imposed by having the xdrive system, but the beauty of these forums is so many enthusiast, many with intelligent minds and passion for bmw's and driving have come up with ways to circumvent the xdrive and still upgrade them to a certain extent. I appreciate the feedback you provided, im excited and looking forward to getting them now

Yeah the ride is great. It's razor sharp and rcomfortable. A lot better then my brothers e46 M3.

Make sure you get proper SHORT bump stops. I know Strut Monkey is accommodating, definitely a special order.

And for the rear you can do M3 arms. Solid subframe bushings, and white line trailing arm bushings.

Front: i believe you can get upgraded OEM arms from fcp and ecs that aren't M3 style.. Good luck!

[chris55552]

Originally Posted by gunnerxq

Yeah the ride is great. It's razor sharp and rcomfortable. A lot better then my brothers e46 M3.

Make sure you get proper SHORT bump stops. I know Strut Monkey is accommodating, definitely a special order.

And for the rear you can do M3 arms. Solid subframe bushings, and white line trailing arm bushings.

Front: i believe you can get upgraded OEM arms from fcp and ecs that aren't M3 style.. Good luck!

Thats exactly what I was needing from someone on this forum, thanks a ton for taking the time to do so. Best of luck

[Mrmigs2011]

Is it n52b30 3sm?

If so take the large disa out and check for damage, then rocker cover off rotate the crank by hand and watch the valve train movements.

The large disa valve centre pin can wedge itself in a valve and cause no compression, missfiring is the first sign.

[gunnerxq]

Originally Posted by Mrmigs2011

Is it n52b30 3sm?

If so take the large disa out and check for damage, then rocker cover off rotate the crank by hand and watch the valve train movements.

The large disa valve centre pin can wedge itself in a valve and cause no compression, missfiring is the first sign.

Yeah it has a 3 stage intake manifold. The rocker cover was taken off today by a shop. All the valves and valve springs seem to be good. Zero compression in cylinder 6 don't know how or why.

[gunnerxq]

Originally Posted by gunnerxq

Yeah it has a 3 stage intake manifold. The rocker cover was taken off today by a shop. All the valves and valve springs seem to be good. Zero compression in cylinder 6 don't know how or why.

Edit: maybe there is a disa pin stuck there. I'll have them check it.

[gunnerxq]

Update:
There's a hole in one of the valves. I believe it's on the intake side. No idea how that happened. Time to look for a new car I guess.

[crashoverride]

Originally Posted by chris55552

It happened to mine at 44k miles, 2 months after purchasing it. Talk about luck, absoloutely no warnig. I will say this though... and it could have caused it. I over used liqui molly anti friction mos2 and ceratec... used too much at too close of an interval. It was an x3 with the n55, and even after the new motor was put in i drove it for a while and literally got rid of it 2 weeks ago. Just wasnt happy with it, it had the base suspension which I didnt like, and I just didnt like the N55 near as much as the N52. It had alot of brute power at 306hp, but to me BMWs are about more than just straigh line performance, Their about balance, handling and Id take a better handling slower car any day over straight line performance. Where I live you can never tap into that power without getting ticket after ticket, so i got rid of it and now my second car is my daily driver, a e90 328i xdrive with a manual transmission. The x3 was just one issue after the other, my transfer case was making a noise and im certain it was on its way out which would have costed alot of money. Back to the liqui moly products. I love ceratec it makes an engine run smoother and quieter but you have to follow the recommended intervals of use which I neglected to do. Lesson learned.

Cool Story(s) Bro.... While the rest of us are busy talking about the topic at hand

[gunnerxq]

I'll never know for sure why the valve burnt out but I'm assuming it could be because a clogged fuel injector. I had a code for cylinder 3 which I replaced. Should have done all 3 since it would of been under FCP warranty.

Last generation that I'm looking into is the F30 without going into M cars.

Has to be a manual.

[lowrydr310]

Originally Posted by gunnerxq

I'll never know for sure why the valve burnt out but I'm assuming it could be because a clogged fuel injector. I had a code for cylinder 3 which I replaced. Should have done all 3 since it would of been under FCP warranty.

Last generation that I'm looking into is the F30 without going into M cars.

Has to be a manual.

That doesn't look burnt, looks like it chipped off, likely NOT caused by a fueling issue. Did you find the piece that chipped off? Maybe some metal did get in there and the valve closed on it. Did you check your DISA valves to make sure one didn't come apart?

I wouldn't be in a rush to get rid of the car just yet. N52 heads are dirt cheap and can be replaced over a weekend if you're mechanically inclined. If not labor isn't even too bad. I'd rather pay to have a head replaced on a manual E90 than trade it for any F30 or later.

[gunnerxq]

Originally Posted by lowrydr310

That doesn't look burnt, looks like it chipped off, likely NOT caused by a fueling issue. Did you find the piece that chipped off? Maybe some metal did get in there and the valve closed on it. Did you check your DISA valves to make sure one didn't come apart?

I wouldn't be in a rush to get rid of the car just yet. N52 heads are dirt cheap and can be replaced over a weekend if you're mechanically inclined. If not labor isn't even too bad. I'd rather pay to have a head replaced on a manual E90 than trade it for any F30 or later.

I never found the chipped off piece, probably came out the exhaust or fell to the bottom of oil pan. Haven't checked the disa valves yet but I have a feeling that one of them went.

I was thinking f30 340i manual but lci with adaptive suspension. But the market is ridiculous.

And you said n52 heads are cheap? I'm guessing a used one off of ebay? So possibly a hit or miss?

And labor wise it's similar to a valve guide seals replacement or more complicated. Because that's 3-5k job. I had my valve guides done about a year ago.

Sorry for all the questions.

Thanks!

Almost forgot, the car still burnt a lot of oil after the valve guide seals were replaced. So maybe it's the rings around the pistons as well?