97 M3 engine problem

[Marknhl]

So, I bought a 97 M3 around a month ago and I love it, it has been great. Previous to today I have been very skeptical that my VANOS is going bad. Today, I drive down the street and around the corner and all of sudden the check engine light turns on, I lose power, (check control OK), I pull over and park it running. Oil is fine, I touch the throttle from the engine bay, try to give it gas, and it stalls out. I turn it back on, now its chugging like an american muscle car. It sounds like something mechanical is slapping around as the engine turns. Not happy. Parked for the time being before my temper goes through the roof :) I will check the check engine code soon and report back.

The first things that come to mind are VANOS and ECU. (ECU failed on my old 94 325 and had somewhat similar symptoms but not quite the same.) Thoughts? Help?! Thanks in advance.

[MasterKwan]

Vacuum leak or coil pack is the first thing that comes to my mind.

[alanilil]

Yup, sounds like a misfire.

Def scan the codes with a Peale tool.

[EricP]

Yup, sounds like a misfire.

Def scan the codes with a Peake tool.

Yep, let's check the code first.. and just to give you some crap: So how long ago did you moneyshift it? :rofl

[LuxoM3]

+1 vaccuum leak...

A rotted throttle body boot is a little more common than catastrophic "one minute the car is running fine, the next, it's sputtering, and sounding like it's going to blow up."

[Marknhl]

Yep, let's check the code first.. and just to give you some crap: So how long ago did you moneyshift it? :rofl

Please forgive my lack of knowledge.... what is a moneyshift? I do tend to drive the car hard.. :D

Peake Tool Diagnosis:

Misfire Cylinder 2

Ok, I think I can think a bit more clearly now... I will try the coil pack and spark plug first and go from there.

[alanilil]

Please forgive my lack of knowledge.... what is a moneyshift? I do tend to drive the car hard.. :D

Peake Tool Diagnosis:

Misfire Cylinder 2

Ok, I think I can think a bit more clearly now... I will try the coil pack and spark plug first and go from there.

Money shift means mechanical over rev caused by mis-shifing.

I'd try clearing the code, inspect slark plug #2 switch coilpacks and see if the misfire moves to a different cylinder. My best guess is a bad coilpack.

[Marknhl]

ohhh, I have never moneyshifted - anything I think - but I have revved the car out intentionally when really getting on the gas. So I'm not sure there's much difference? I didn't hit the rev limiter, I shifted just before where I thought it was.

Ok, I'll do this soon and report back, hopefully with successfully results in replacing the coil pack! Thank you for the help.

[LagWagon]

Retighten the spark plug as well while the coil pack is off

[EricP]

ohhh, I have never moneyshifted - anything I think - but I have revved the car out intentionally when really getting on the gas. So I'm not sure there's much difference? I didn't hit the rev limiter, I shifted just before where I thought it was.

Ok, I'll do this soon and report back, hopefully with successfully results in replacing the coil pack! Thank you for the help.

Don't worry I was just giving you crap :) A lot of new drivers like to moneyshift they car and post a thread trying to troubleshoot and fail to mention the massive mechanical over-rev. lol.

Plug, coil swap, etc.. start there.

[RRSperry]

Just to be clear, It's perfectly safe to rev the piss out of the car. It's ok to bang into the rev limiter when you accelerate. that's what it's designed to do. (it's not fast, but that's another story...)

Shifting into the wrong gear and having the wheels drive the engine is NOT a good idea. (trying to shift to 4th because you are fast and furious and have the red mist in your eyes, but actually shifting into second, thus having the wheels drive the engine to about 9.5K RPM. The valves float, pistons hit valves, valves bend, engine dies.= MONEY SHIFT) No electronic rev limiter can prevent that.

[Marknhl]

Just to be clear, It's perfectly safe to rev the piss out of the car. It's ok to bang into the rev limiter when you accelerate. that's what it's designed to do. (it's not fast, but that's another story...)

Shifting into the wrong gear and having the wheels drive the engine is NOT a good idea. (trying to shift to 4th because you are fast and furious and have the red mist in your eyes, but actually shifting into second, thus having the wheels drive the engine to about 9.5K RPM. The valves float, pistons hit valves, valves bend, engine dies.= MONEY SHIFT) No electronic rev limiter can prevent that.

That is a scary scenario indeed. And that's good to hear about revving the engine because I do that plenty :D Just need to feel the power band.... :D I try to keep it under 5,000 rpms, I suppose that isn't terrible? Anyway, I probably won't change haha

Ordered a full set of NGK copper core plugs (heard some bad things about Bosch and I really don't want Autolites, idk why, just can't) and one new coil pack - $71, ATM brand. Yes, I'm being hasty and assuming it is the coil pack, if not I will return it. Also, the gentleman at Napa stated that coil packs usually go back as a result of improperly gapped spark plugs, which will then require the coil pack to put more power to the plug in order to get spark. Thus, I ordered a full new set of plugs. I could have re-gapped them, but I don't know when they were changed last.

[EricP]

BKR6E ftmfw

[Marknhl]

BKR6E ftmfw

Lol what is BKR6E?

Lol nvm google told me. Well good deal, idk if those are the exact NGKs I got, but hopefully they are. I'll find out tomorrow.

[Marknhl]

Which direction does cylinder 1 start from? Assuming it starts from the front I replaced the spark plug and coil pack with no change. However, today I will clear the code and try again, also try the cylinder order starting from the back and maybe I just had the wrong cylinder.

Also, the coil pack I bought is round instead of square, not sure that this makes any difference, it was listed as for my car.

Anyone on the previous question?

Also, I should have kept scanning through the codes... I have a misfire in cylinders 1 AND 2. Is it possible that two coil packs went bad at the same time? Otherwise what would this be?

[RRSperry]

1 Front, 6 back...

Yes it's possible for 2 coils to fail. It's also possible that it's a fuel pressure problem, or an injector problem, or a vacuum leak, or bad plugs, or ... That's why most people on internet forums are at best 1/2 assed mechanics.

And just because you so something and it fixes the symptom, doesn't necessarily mean you fixed the problem...

[Marknhl]

1 Front, 6 back...

Yes it's possible for 2 coils to fail. It's also possible that it's a fuel pressure problem, or an injector problem, or a vacuum leak, or bad plugs, or ... That's why most people on internet forums are at best 1/2 assed mechanics.

And just because you so something and it fixes the symptom, doesn't necessarily mean you fixed the problem...

Thanks for the info in the first sentence but I fail to see the point of the rest of your comment. It's obvious information that it could be something else and that the problem isn't always fixed. Moreover, I'm posting here because I expect someone with more knowledge and experience will look at that information and know better how to resolve it than me. So us half assed mechanics still get the job done 90% of the time and I'm pretty comfortable with that...

[Marknhl]

Today I replaced all spark plugs and swapped coil packs in cylinders 1,2 with 3,4. Drove it down the street and I get a check engine code for misfire cylinder 1. I'm expecting it has to do with fuel at this point. Topped off the tank in case I got bad gas (I doubt it). Later today I will see if I can run some tests on fuel pressure into the rail and exiting the rail. My buddy says he may have access to the tools do this with. I will be looking up the numbers for these items, if anyone has quick access to them that would be great.

[desynch]

^ from your original post you said misfire was on cylinder 2, now it's migrated to 1?

Sounds like a problem a buddy of mine and me as well had.

His throttle boot had a major tear. If there is a MAJOR tear (if you can stick your fingers through the hole), this will cause misfires. If you get a CEL and it's always a single misfire in the same one and only cylinder, swap the coil pack. If it's misfiring in 1, change the pack from that to another cylinder. If code moves when you move the packs, replace ALL coilpacks with new ones.

I happened to have 1 coil pack that failed, the other 5 were fine. It sounded like a Subaru with an aftermarket exhaust when the car was in limp mode (ran on 2 cylinders?). Replaced the coilpack with a new one, and it worked for a while, but you would get constant hesitations. Bought 5 new ones along with that 1, and the car's been fine ever since.

None of us had any fuel delivery issues. Good condition spark plugs I have found, hardly cause these symptoms.

[Marknhl]

^ from your original post you said misfire was on cylinder 2, now it's migrated to 1?

Sounds like a problem a buddy of mine and me as well had.

His throttle boot had a major tear. If there is a MAJOR tear (if you can stick your fingers through the hole), this will cause misfires. If you get a CEL and it's always a single misfire in the same one and only cylinder, swap the coil pack. If it's misfiring in 1, change the pack from that to another cylinder. If code moves when you move the packs, replace ALL coilpacks with new ones.

I happened to have 1 coil pack that failed, the other 5 were fine. It sounded like a Subaru with an aftermarket exhaust when the car was in limp mode (ran on 2 cylinders?). Replaced the coilpack with a new one, and it worked for a while, but you would get constant hesitations. Bought 5 new ones along with that 1, and the car's been fine ever since.

None of us had any fuel delivery issues. Good condition spark plugs I have found, hardly cause these symptoms.

Thanks for the reply. Well sort of... When I originally checked the code, I saw a misfire cylinder 2. However, at this point I made a mistake. I did not keep clicking through the scan tool to search for codes. So I'm not sure if at that point I only had once CEL code or two. So the code I originally saw was misfire cylinder 2. I bought new plugs and a new coil pack and swapped it in. Still ran like garbage. Then I decided to try and clear the code (maybe that was why it wasn't running properly at this point), except when I did that I checked the codes again to make sure they were the same, and I kept clicking through and discovered ANOTHER code. So basically, at the same time I had misfire codes in cylinders 1 and 2.

At this point, I removed the new coil pack, reinstalled my old one. However, this time I moved coil packs for cylinders 1,2 to cylinders 3,4 to see if the CEL misfire code moves with them. I cleared the CEL code and then drove down the street and the CEL popped on again. The code is currently saying misfire cylinder 1, thus it did not change cylinders when I moved the coil pack. This leads me to believe there is not an issue with the coil packs (and the plugs are new, so not them either). If my logic to this point makes sense, I have eliminated plugs and coil packs as the possible culprit. I also just went outside and verified that the intake boot is in good condition. Again, if my logic is correct, the issue must be in the fuel delivery system somewhere.

Fuel pressure out of the back of the rail (front of the car) is 37 lbs. Compression test on cylinders 1 and 2 shows 60 psi and cylinders 4 and 5 show 120 psi. That's a bad sign. As my friend who is looking at it with me noted, it sure sounds like it's sucking for air on the intake side. I don't see anything loose though. Going to spray soapy water around to see if it is intake manifold gasket...

So I'm fairly certain my VANOS is bad, but does anyone know if that will affect the compression of my cylinders?

Also, what about my camshaft position sensor being bad? This article at Pelican says, " your car will run very erratically or perhaps not at all." if the camshaft position sensor is bad.
http://www.pelicanparts.com/bmw/techarticles/101-Projects-14-Cam-Sensor/101-Projects-14-Cam-Sensor.htm


Or a headgasket.

[fun2drive]

37 psi is way off. It is supposed to be 43 psi plus or minus 3 psi. However your engine should still run OK not terrific but OK. I don't think your issue is fuel pressure or quanity because you should see issues with other cylinders.

The next logical step is to pull the injector in 1 and move it to another location say 3. See if the move results in the problem migrating to 3.

I think vacuum leak has been mentioned and it could be possible but more investigation if in order regarding spark (covered) and fuel (injector move).

I would do that see what the results are and if it still is 1 then keep checking. VANOS is something that affects all the cylinders since it affects the timing of the intake cam...

[desynch]

If your compression numbers are that low I think you may have a different story to worry about...

Cylinders should be 5-10% of each other. Mine are 178psi +/- 3psi.

[EricP]

Unexplained misfire that doesn't clear up from plug or coil swap, misfire alternating on cyls #1 and 2.... if you don't have any coolant or oil mixing, I would say the head gasket may have failed between cyls 1 and 2. :/

I would do another test to confirm and then get ready to get dirty. But think how good it'll run afterwards :) Could a bad seal or something on an injector jack up your compression numbers? But then you are having low compression on 2 cylinders..

[Marknhl]

Yes, I am expecting a failed head gasket between cylinders 1 and 2 as well. I'm going to be purchasing a kit to do a leakdown test tomorrow. Hopefully I can check compression with that as well... The gauge was being funny today and I want another source of authority on the issue to be sure. Also on cylinders 4 and 5 it was 120 psi, which is a lot less than 178.

I checked my paperwork today and the head gasket was replaced on the car 7,000 miles ago, but four years ago, at Exten's in Rochester. I'm considering giving them a call to ask about this even though I doubt they will do anything for me at this point.

My two major concerns with replacing the head gasket are removing/reinstalling the camshafts and setting the timing. I will be doing more research if the head gasket is the issue.

[Marknhl]

The results are in... there is blowby between cylinders 1 and 2. Looks like a headgasket. I'll be searching for some tutorials as well as calling Exten's tomorrow to find out their response about having done the headgasket 7k and four years ago and it failing. We'll see...

[Marknhl]

Update... Took two days to get the head out which was yesterday. A short amount of time further tonight got the camshafts removed.

Inspection by a former Saab master mechanic from Dorschel in Rochester says that a poor milling job caused the head gasket to fail prematurely. Will post pics shortly, though I'm not sure the pic is that great of quality. I will be taking the head to a machine shop tomorrow for further inspection and diagnosis.

I've taken about 100 pictures during the process, I could post them somewhere accessible to forum members if someone ha an idea of where that would be. Flicker maybe?

Extens manager Adrian did not exactly welcome my first phone call regarding the issue, the tone of her voice belied that she was very annoyed that I had even called. I then commented on her annoyance and she denied it but the tone did not change. I'll be interested to hear what she had to say about the fact that the (in house I believe?) milling job they did was terrible... As well as what they are going to do about it, since it caused their head gasket work to be a waste after a mere 7,000 miles.

[Marknhl]

I'm not sure that you can see what I'm talking about or not... I will get a better close up picture tomorrow. If you run your finger along the head between cylinder 1 and 2 you can feel that there's two super small steps and its just not smooth.

[desynch]

You could always go ahead and post pics on Photobucket or Flickr. I'm documenting my clutch/flywheel job and am posting pics on my Photobucket.

[Daz4life]

Don't feel too bad about this ! My clutch went bad the day I drove my M3 home from the stealership. Cheapo PO replaced the disk only and the throwout bearing came completely apart. 3-5 months later car overheated while I was driving on the freeway and I didn't notice for about 15-20mins of driving cause it still felt the same. That resulted in a head cracked in 3 places. So ignorance cost me almost $4k. I still get to change out my rear exhaust manifold(broke at the flange for the 2nd time) and motor mounts tomorrow. I should of known better than to buy a Bimmer with 181k without checking it out as I should of.

[Marknhl]

You could always go ahead and post pics on Photobucket or Flickr. I'm documenting my clutch/flywheel job and am posting pics on my Photobucket.

Ok, just did it on photobucket. Pics thus far should be able to be viewed here:
photobucket.com/marknhl
or
http://s1194.photobucket.com/albums/aa380/marknhl/

Note that the pictures do not appear to be in any specific order, though they are in my folder on my computer.


Don't feel too bad about this ! My clutch went bad the day I drove my M3 home from the stealership. Cheapo PO replaced the disk only and the throwout bearing came completely apart. 3-5 months later car overheated while I was driving on the freeway and I didn't notice for about 15-20mins of driving cause it still felt the same. That resulted in a head cracked in 3 places. So ignorance cost me almost $4k. I still get to change out my rear exhaust manifold(broke at the flange for the 2nd time) and motor mounts tomorrow. I should of known better than to buy a Bimmer with 181k without checking it out as I should of.

Thanks for the note and sorry to hear you had so many troubles with your car! I'm liking the experience of doing the work and will be happy once the job is over for the simple fact that I studied it, figured it, and did it. Then I'll know my car pretty much inside and out since I've done so many other jobs on my previous 325IS. The big downfall is just that is has cost so much money, a problem which you have had also. Moreover, the work was done by a professional shop that I've heard great things about... it just doesn't make sense for them to have done such poor work... I paid more than I was planning for this car because the PO was exceptional about maintenance that was done on the car. Too bad the mechanic he paid to do the work didn't do a good job on this ultra important part of the vehicle. And I wouldn't be as upset with the shop either, if they had a little bit more concern with regard to an issue that was first suspected to be there fault, now looking at the head I'm certain of it, and tomorrow I expect the machine shop will confirm it... On a positive note, I'll be very please once she is back on the road and pulling hard!! Regardless, I'm still completely in love with the car LOL

[Daz4life]

Mine cost me so much out of the need of the car and not enough time, knowledge of BMW's and special tools. I got raped with the clutch cause its a basic so i could of done it myself but at the same time I would have surfaced the flywheel instead of changing it out and then I'd back in the same boat. The head, I found a new head for $600 without cam but with a fresh valve job(still had syrand wrap on it), I didn't have the special tools to do the timing so i piad my neighbor to do the job since he knew how(he owns a e30 m3) and had the special tools(plus I was on Active Duty at the time).

Change out the intake manifold while you have it off to the s50/m50 if you haven't done so already.