BIG Problems... dead engine?

[SteelGreyM]

I need some help sorting out the weirdest issue.

I was having some fun ripping it one day. I ended up hitting the top speed limiter. The car didn’t like that at all and started acting funky ever since then. I had a misfire on cyclinder 1 that wouldn’t go away no matter what. Then a few days later the battery completely died even though it was perfect just a few days ago. As in the car was hard to start even with jumper cables.

so I swapped coils and plugs from other cyclinders but no luck. The misfire was still there. It should be noted that even though the car detected a misfire, it felt and ran perfectly smooth to me. On that exact same test drive it also said I have another misfire on cyl 6.

so I swapped those plugs and coils too. Nothing. At this point I thought maybe my valves are way out of adjustment some how but highly unlikely because I did a valve adjustment just 20k miles ago. So I went ahead and did a VANOS overhaul along with my valve adjustment AFTER doing VANOS. I followed the instructions to a T and my timing was perfect after.

and for the first 50 or so miles the car had NO issues. Cut to today. I’m driving back home and I see some smoke coming out of my exhaust. Im not far from home so I just keep limping it. Just a few miles from home the car starts misfiring badly and I pull into a lot. I start it once more, the car hesitates to start and it knocks for a second or two then the knock goes away. It runs pretty rough and sounds super deep. Eventually it just dies.

My rod bearings were done by a reputable shop just 20k miles ago. Im on top of all of my engine maintenance. My car currently has 140k miles on it.

It should also be noted it is eating a lot of oil. I’m talking in approximately 80 miles it burned a good 1/3 of a liter of oil. Almost all of it out the tailpipe.

what is so mind boggling about this issue is that it all happened so quickly. It didn’t deteriorate over time.

I also spoke with Raj at Beisan and he did not think the VANOS had to do with this issue. And considering I triple checked the instructions and the timing when I was done I doubt I messed that up.

I’m almost thinking it could be valve seals or piston rings. Something is letting oil pass through into the exhaust. Any input is appreciated. Thanks guys

[heinzboehmer]

I ended up hitting the top speed limiter.

Wait, top speed limiter as in 155 mph or do you mean rev limiter?

Also, when you say you had a misfire on cylinder 1 do you mean you could feel it misfire or that's what the codes were saying? Any other codes present?

[stash1]

Ehhh, I would recommend doing both a compression test and a leak down test. It doesn’t look good for your engine though...based on your description.

[gabylonfive]

what color was the smoke coming out of your exhaust? agree with ^^^ - i'd do a comp test asap.

[SteelGreyM]

Wait, top speed limiter as in 155 mph or do you mean rev limiter?

Also, when you say you had a misfire on cylinder 1 do you mean you could feel it misfire or that's what the codes were saying? Any other codes present?

I ended up hitting the 155 speed limiter but my RPMs were only at 6k. Although I was pushing it hard to get to that point.

A few seconds later I had a SES light. The car ran perfectly fine so I was somewhat confused. I got the scanner out and it said misfire cyl 1. I just cleared it and went on with life. A day or so later I would get the code a few minutes into driving even though the car felt perfectly fine. No smoke at this time. Didn't run horribly. If the CEL was not there I would not have known there was a misfire.

I parked it and swapped plugs and coils from cyl 1 to two. Still got the cyl 1 misfire code. Again the car ran perfectly fine. I didn't drive it that day but I tried once again the next day to drive it. This time it started saying misfire cyl 1 and 6. I got super suspicious that it has something more to do than just plugs.

At this point I thought it may be fuel system because I was pretty certain my coils and plugs were fine after the original work. However I never did any work to the fuel system because my VANOS repair stuff came in. I did the vanos stuff to a T. Im very confident that is all correct. Then we get to today and its eating oil and dumping it out of the exhaust.

The only codes I have gotten are just the misfire codes. Never more than 2 cylinders. And the car seemed to run perfectly fine even with those codes present until today when it finally misfired badly and just died.

Heres where im at. If theres oil coming out the exhaust that means a major seal is leaking. I can only think of piston rings or valve seals. Any other seals that allow oil to get to the combustion chamber.

Are there any tests I can do to decipher if it's one or the other?

Sorry about the big writeup im just trying to be super detailed and transparent here. I appreciate the help.

[Halftim3]

Come back with compression numbers.

[SteelGreyM]

Ehhh, I would recommend doing both a compression test and a leak down test. It doesn’t look good for your engine though...based on your description.

what color was the smoke coming out of your exhaust? agree with ^^^ - i'd do a comp test asap.

Come back with compression numbers.

I will be doing a compression test ASAP. The smoke was whitish blue. Pretty hazy. Reeked of oil. The car is burning oil.
Also coolant temps are perfectly fine and it doesnt look or smell like coolant smoke ( I've seen that before.)

The smoke has never been black.

[Stock_E46_M3]

Sounds like low compression on # 1. Especially since the code didn't jump cylinders once you swapped them around. Did you check your plugs as well ?

[SteelGreyM]

Sounds like low compression on # 1. Especially since the code didn't jump cylinders once you swapped them around. Did you check your plugs as well ?

I took a photo of my cyl 1 spark plug the first time i swapped plugs and coils. It was very dark and dirty especially for being only a year old. Almost oily. This was before my exhaust was shooting out oil though

[heinzboehmer]

Are there any tests I can do to decipher if it's one or the other?

A leak down test will rule out piston rings (headgasket and correct valve seating too). I agree with the others, do a compression and a leak down test first and if both come back fine you can start looking at other potential sources for this issue.

[SteelGreyM]

A leak down test will rule out piston rings (headgasket and correct valve seating too). I agree with the others, do a compression and a leak down test first and if both come back fine you can start looking at other potential sources for this issue.

Thanks everyone. I have a compression test scheduled for tomorrow. Im seriously praying that it is valve seals and not piston rings. The VANOS job I just did gives me the confidence I need to remove cams. I mean I was 80% there. Sprockets were off and everything.

Im so surprised at how quickly this problem has overtaken my engine. I thought that things like this usually deteriorate and get worse over a few thousand or at least hundred miles. But no... less than 40 miles is all it took from the first puff of smoke to barely running.

If I had to take a bet my money would be on valve seals. I have more lots of smoke on idle and on deceleration. In fact I noticed that the more I pushed the gas the less smoke would come out. Wouldn't that be the opposite for piston rings?

Again thank you guys so much. I'm not sure what I would do without this community.

[Titaniu//M]

All you need to do a compression test is an auto parts store compression tester with a 12 mm fitting. Super easy to DIY, definitely not worth paying someone to do it.

https://forums.m3cutters.co.uk/threa...k-guide.14218/

[SteelGreyM]

All you need to do a compression test is an auto parts store compression tester with a 12 mm fitting. Super easy to DIY, definitely not worth paying someone to do it.

https://forums.m3cutters.co.uk/threa...k-guide.14218/

Thanks for posting this. ill do this instead of paying someone. Could I risk additional engine damage by cranking it for that long?

[eacmen]

Thanks for posting this. ill do this instead of paying someone. Could I risk additional engine damage by cranking it for that long?

No. you pull the fuel pump relay and just cycle the starter motor. Make sure your battery is charged. No more damage is likely. If you have an air compressor a leakdown test is almost just as much effort and will lead you to the root cause versus just "compression is bad do a leakdown".

What race track were on you on going 155mph?!?

[Kdubski]

Headgasket.

dealt with weird misfire situation. Followed advice of forums for compression test. Numbers inconsistent. Open up the head and turns out burnt out between cylinders 1-2,4-5,5-6.

De-carbon your pistons while you have the head off.