How do diagnose a sudden and disturbingly unsettling cold-engine misfire (vanos?)

Originally Posted by bluebee

I have increasingly felt some undetermined "hesitation" lately when accelerating, so, something is amiss ... and I'll keep my eye on that.

[SIZE=1]Note: Yes, I lived back east so I know what a Californian labels a bad "storm" is really nothing special for you nor'easters; however, you must realize living out here just changes your perspective on the severity of nature, that's all.

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FYI, hesitation was my only symptom prior to the Vanos seal change. No hesitation after the seal change. Some more anecdotal "data" to ponder.

Another 6"-8" last night! A mere dustin'. However, we are getting bumper crop this year.

I have not read all postings here, so I am not certain if everyone had similar experience, but I always get these mysterious misfires in the spring or more specifically when the temperature differential between the moment when I shut off the car and I start it is significant. I know to turn the engine off and on and that always fixes the problem. Sometimes I have to repeat the off/on procedure a couple of times. A good friend of mine who works on BMW told me once that this is a problem many BMW cars have. I don't remember his explanation, but I do remember he told me that turning the car off and on should fix it. I don't want to discourage anyone from changing their vanos seals. I bought mine some time ago and need to find time to put them in. I am just thinking that the underling cause for this erratic behavior of our cars might be a software problem that has to do with the ambient temperature and the mixture preparation. My car has been acting up every spring now for 4 years. It never does it more than 3-4 times per "season". I am certain it has to do with temperature and humidity. I am not certain if it is a software problem. This is a hypothesis, although many cars have software problems, being the computers that they are nowadays.

Originally Posted by mmihailov

I always get these mysterious misfires in the spring or more specifically when the temperature differential between the moment when I shut off the car and I start it is significant. I know to turn the engine off and on and that always fixes the problem.

It's a very interesting hypothesis ...

• An as-yet-unknown temperature differential between the shutdown:startup activates a software glitch
• That software glitch causes a minor misfire (greater than once per 200 revolutions)
• That minor misfire is large enough to cause a permanent fuel shutoff
• Once the fuel is shut off, the engine runs roughly until the ignition is cycled (and DTC codes are potentially thrown, along with the potential for a related SES)
• It is said you should wait 30 seconds between cycles
• Once cycled, the fuel shutoff is resolved
• And, inexplicably, the misfire does not reappear (until conditions are ripe again between temperature shutoff and restart)

Indeed, this is an interesting hypothesis.

Now, the key question (for any hypothesis) is HOW to test it???

Note: I suspect the reason it doesn't always work the first time for you is that you purportedly need to wait 30 seconds of shutdown before restart.

Originally Posted by bluebee

It's a very interesting hypothesis ...

• An as-yet-unknown temperature differential between the shutdown:startup activates a software glitch...

Indeed, this is an interesting hypothesis.

Now, the key question (for any hypothesis) is HOW to test it???

[/I]

Bluebee, by the of the day, when I put my 525i in the garage, the car body has ambient temp. -4F. In the morning when I start my car in the garage, the car body temp is +68F. Its due to the heaters inside the garage. We have positive differential delta +72F.

To create negative differential delta I guess we need to do nothing. Because morning is usually colder than evening.

Personally I can not confirm that "every time I create temperature differential - I have rough idle". But I am 100% sure that I experience rough idle for only last 2 years in my 10 years old car, 70K miles driven. And usually rough idle apears when car was not used for a week. I believe these two condtions should be in "top5- how to create rough idle by youself"

Just an idea: if small and stupid ODBII scanner-eraser bug is connected to the car, and programmed to erase some particular missfire codes by the time they appear - rough idle problem could be tricked.

what do you think?

Originally Posted by nkulinich

Just an idea: if small and stupid ODBII scanner-eraser bug is connected to the car, and programmed to erase some particular missfire codes by the time they appear - rough idle problem could be tricked.

what do you think?

That's only a bandaid solution to this problem. But it will work until it gets worse and worse

Originally Posted by mujjuman

it will work until it gets worse and worse

Or, until the next mandatory smog inspection.

Interestingly, the sudden and severe cold-engine misfire with resulting fuel shutoff still has not occurred again since that fateful first day when this thread was started.

I've had 'other' misfires, and vacuum problems, but not that sudden and obvious shuddering where the car would barely move down the driveway.

I think there could be a whole bunch of potential culprits:
- Vanos
- Engine computer problems with certain temperature changes
- Engine computer problems with starting the car at one temperature just to move it and then letting it sit overnight to a different starting temperature
- etc.

And, a new idea, for a cold-start single-cylinder misfire with resulting fuel shutoff popped up in the E46 forums today (M54 engine) ...
- E46 (1999 - 2006) > Misfire on cold start? Check in here...

Originally Posted by silver69camaro

Since about last year, our 2003 330i was having a problem with cold-start misfires. It would vary as to what cylinder was misfiring, but would normally happen on #5. Typically it would misfire enough to throw a CEL, resulting in fuel-cutoff to that cylinder - a re-start would usually cure the problem. It would happen once a week or so, usually when it's colder (less than 40 degrees or so).

Well, moving to more recent times, it would happen more and more often, regardless of temperature. Car has about 80K now. Things that I checked, in no particular order:
1. Coils (swapped and replaced, confirmed good spark during misfire condition)
2. Injectors (swapped and replaced, confirmed working properly during misfire condition)
3. Coil electrical harness (dissasesmble and inspect for breaks & shorts)
4. Smoke-check for intake leaks
5. Replaced intake boots (small crack)
6. Replaced DISA valve (broken)
7. Cleaned ICV
8. Plugs (replaced, all looked good)
9. CVV checked OK

There is probably more, but I can't think of it right now. I thought more and more the condition was oil related due to the temperature and re-start cure. I knew the lifters in these motors could be troublesome, and several experienced BMW techs confirmed that.

Well, when the lifters go bad in these motors, the lifter collapses and doesn't lift the valve all the way; meaning the cylinder isn't getting a complete air/fuel charge. The lifters scour the lifter bore in the cam ledge, creating escape passageways for the oil to travel instead of pumping up the lifter. Why a hardened iron lifter and riding in an aluminum bore is beyond me - but I know many manufacturers do this.

Moving to last week, I finally disassemble the top end of the engine. Sure enough, about 4 lifters had significant scouring, and 12 others were lightly damaged. The intake cam ledge was needing replacement, but the exhaust looked acceptable. That leaves me with one good cam ledge and 8 good lifters. I purchased a good used ledge ($200 vs. $460 new) and replaced the 16 bad lifters. Using the proper tools, the job took about 10 hours, which is on par with dealer quotes ($3500 parts & labor).

Parts total:
Lifters - $272
Cam ledge - $200
VC Gasket - $20?
Cam-lock tool - $60
Cam timing tool kit - $225

Total of about $800. From a difficulty scale 1 to 10, I'd give this a 6 only because of the time involved. If you know how engines work and can follow the TIS instructions, you can do this job.

Good news is, engine runs great in the morning. Not a hint of misfire and absolutely no lifter tick. If you have a troublesome cold misfire that you can't seem to figure out, the lifters are a good possibility.

Wow, nice find, Bluebee. It was interesting to read about how the lifters fail, and it wouldn't have occurred to me that they could induce a misfire. With the recent advent of all the electronic technology, more and more systems are interrelated in mysterious ways.

Originally Posted by bluebee

Interestingly, the sudden and severe cold-engine misfire with resulting fuel shutoff still has not occurred again since that fateful first day when this thread was started. ..

bluebee, how it could be the lifter if the rough idle problem does not appear on daily basis, or wintertime only.

If we have lifter damaged, it should cause rough idle every start, or every cold day.

In my personal case I had at least 10 rough idles in 2008-2009 winter, but in 2010-2011 winter only one rough idle was reported by my wife. Does this mean my lifter gets better?

The only difference I see is the weather (humidity), and I changed motor oil from unknown to thin 0w40 Arctic.

Originally Posted by nkulinich

bluebee, how it could be the lifter if the rough idle problem does not appear on daily basis, or wintertime only.

I have no idea. You'd have to ask the guy that posted that diagnosis. I gave the link already so you should ask him!

Originally Posted by bluebee

I have no idea. You'd have to ask the guy that posted that diagnosis. I gave the link already so you should ask him!

At the beginning the guy who was doing rebuild on lifter system mentioned that the problem happened when the weather is colder than 40F/4C.

This is a perfect temperature to build a condensate early in the morning. Humidity will do the job.

This winter I opened oil changing cap on the engine in the morning and was surprized with WATER condensate (ice) under the cap. I also see some water (melted ice) coming out of exhaust side when I start my car in the morning.

The rough idle cold start problem could be related to condensed water somewhere in the car: inside the engine -vanos, outside - coils, or even ice chocked exhaust.

Regarding cold-start problems ...

Pay attention to the little vacuum hose in the middle of the CCV, based on these warnings from PhilH on another forum today (thanks Doru for pointing this out):
- Cold start issues, Indie VS. You

Read post #15 where PhilH says:

[The DISA] was a big problem, but not likely the cold start issue.

The Crankcase Vent Valve was apparently changed by the previous owner/ mechanic, they did not change the associated hoses with it, although the hoses were not the culprit here I did have them replaced. When they replaced the ccv they did not realize that some of these engines have a small vacuum hose attached, and some get that nipple plugged, mine gets the nipple plugged but they did not do it.

It caused one of the connections to overheat and melted the connection point, causing the small leak which wasn't enough to turn on the check engine light, into a big leak which did.

And that is why the cold start issue progressively got worse, every time I drove it melted a little more. So for all four hoses, the ccv valve and the intake runner valve it ran me $676, not terrible I think. Indie told me the check engine light was out as soon as he started it, he didn't even have to clear it.

Here is the pic of different version of CCV (w. small vacuum nipple plugged)

I know this has been a while and this is my first post, but being from the UK I normally use a different forum.

Since I bought the car I have had a problem whereby when starting the engine from cold there is a definite miss, although it never used to trigger any warning lights. Then it started triggering the exhaust emissions light and scanning the car using INPA revealed that it is:

242 cylinder 5 burning failed

Therefore it only affects one cylinder and also, once the engine has been running for around 30 seconds and the revs lower the miss stops. I believe this is all similar to previous examples shown on this thread.

However, I wish to diagnose this so that my car is working properly. I have added to the following quote in colour.

Originally Posted by bluebee

Never one to shirk my duty (and stick my neck out) ... I'll make the first pass at what below satisfies BOTH requirements of being (probably electrically) reset with the next ignition cycle and affecting a single cylinder #4.

1--bad fuel (no on both counts) (no on both counts)
2==trash or gunk in fuel (no on both counts) (no on both counts, although this is the definition of bad fuel)
3---spark plug valve cover seals (yes on only one count, no on the other) (could affect a single cylinder, but would not likely reset with ignition cycle)
4---head gasket leak, or cracked block (yes on one count, no on the other) (this would not likely reset and would more than likely cause misfires in multiple cylinders)
5---bad plugs (yes on one count, no on the other) (could affect single cylinder, would not reset)
6==coil pack or boot (yes on one count, maybe on the other) (affects its own cylinder, unlikely that a reset would magically allow this to work again)
7---bad 02 sensors (no on both counts) (these are not used on startup, the fact that the car operates normally following startup almost proves that these work)
8---bad maf (no on both counts) (would definitely affect ALL cylinders)
9---bad injector (maybe yes on only one count, maybe no on the other) (depends on what bad means, if the injector is passing then the theory that fuel is deposited into the cylinder overnight which then presents an incombustible mixture later on might be a good one. Once this mixture has been flushed out by the air being compressed within the normal ignition cycle is resumed)
10---crack ring (yes on one count, but certainly no on the other) (this would only affect one cylinder and could expand sufficiently to cause less of a problem when the engine is up to temperature)
11---cam shaft sensor (hmmm... if there is only 1 sensor, then no on both counts) (there are two of these, and they work over ALL cylinders, doubtful that these could cause this problem)
12==crank sensor (hmmm... same answer as cam sensor) (I would say that this works as once the engine is back to normal operation there are no problems)
13---bad ground wires (yes on one count, probably no on the other) (bad ground wires for what? coils? mine has ONE ground wire and would affect ALL cylinders)
14--- bad fuse or relay (no on both counts) (there is no way this would reset itself)
15---bad wireing (yes on one count, probably no on the other) (wiring for what? this doesnt reset)
16--- dme, or ecu (yes on one count, maybe on the other) (it is possible that this is throwing the initial fault and forgetting about it, although unlikely.)
17--intake manifold gasket leak (yes on one count, no on the other) (this should have an affect on more than one cylinder and shouldnt reset)
18--ccv--aka pcv (hmmm ... methinks no on both counts) (should cause problems for ALL cylinders)
19--icv--idle control valve (hmmm... don't know enough to say) (this would cause a permanent idle issue)
20--tps==throttle position sensor (seems to be no on both counts) (not sure what this has to do with anything)
21--Vanos== (this would affect ALL cylinders)
22--Carbon deposits on valves and seats== (this would not be reset)

So far I have tested the coils/spark plugs and the problem is still apparent. I think I will go down the fuel injector route next as that seems probable.

Mike

NOTE
I am aware that I own a 320Ci, however, it has a 2.2l M54 engine.

Here in Russia, some people like to do "Wynns" chemical or "ultrasound" mechanical injector cleaning at yearly basis.. As for "wynns" injector cleaning, this is simple. Mechanic has to plug a hose with wynns cleanout fluid somewhere in fuel supply line, start the enginge and keep it running idle for a while. $50 procedure, but you have to change dirty spark plugs after it.

It is believed injector could be clogged and shape of the jet could be affected, (instead of spray, you get drops) which could lead in misfire, loss of power and starting problems.

You can try wynns. or you can get injector out of the engine and visually check if it creates spray in cyl 5. But, if it was me, I would start with check of compression in cyl 5.

Well started the car this morning, although it didn't register a misfire or cause any misfire symptoms the INPA showed that cylinder 5 was running very 'rough'. The readings climbed progressively to quite a reasonable peak, and the dropped as the car dropped its idle speed.

I also tested the injectors using the screwdriver method, all were ticking away happily.

So this doesnt rule out the injectors leaking, however, it is still working. We knew that anyway as the car performs perfectly once warm.

Originally Posted by hontoir

this doesnt rule out the injectors leaking

This brand new DIY today from Doru:
- E39 (1997 - 2003) > Injectors replacement and/or servicing DIY

... mentions a particular cold-weather injector o-ring problem known to BMW ...

Originally Posted by doru

1.) Over time, the injector O-rings just like almost any rubber, will deform, loose elasticity, change some its properties. Some effects are deteriorated mpg (for some), or fuel leak for others. The lower mpg (I experienced it too) is due air getting sucked in - just like a vacuum leak. This can be tested with a COLD running engine (in the morning, first key) and some carb cleaner - spray it around the fuel rail, and if there is a rpm surge, you found it. Very simple. When the O-rings are gone, one is responsible for a lean condition, the other one will leak fuel (I thought I had the latter, but it wasn't true). If fuel leaks, or if you lose mpg due to injectors absorbing air (lean situation), new O-rings are the cure.
2.) For the M54B30 (applies to e39 530, e46 330, X5 3 liter, z3/z4 3liter)engines manufactured I believe up to 2006, there is another issue. It's the injector himself. It seems that the batch of Siemens VDO injectors for this particular engine will deform over time (ever so slightly), allowing the fuel to mist under the hood through the fuel rail, when the car is started in cold weather. The condition is a cold engine and temperatures below -20°C (the car does not need to be parked outside, it's enough if the garage has the temp around 0°C - 2°C). Raw fuel smell will waft into the cabin a few minutes after starting to drive under these conditions. I witnessed myself the fuel mist/vapours coming out of the fuel rail. It's scary, because the engine has all kinds of electrical gizmos, and a small spark can be the end of the car's life (and maybe the driver too). I tried changing the O-rings, but it did not do the trick - I still had the raw fuel smell at cold starts and cold ambient temps. The mpg started to get back to normal though. Then I found out that BMW had an internal bulletin concerning those injectors, and there is a new batch of Siemens VDO injectors that apparently do not exhibit the deforming issue. This happens only when it's real cold, and the z series is driven mostly in warm weather, and until not too long ago, even the e39 were stored during winter (not me). More 330 had this issue, and lately the X5 with the i6 engine.

So here we go:

If you have a lean situation (mpg will start going down ever so slightly, but steady), you will need O-rings:

Vibration on a cold M54 engine with a misfire on one or two cylinders and a fuel shutoff is due to Hydraulic valve lifters wear / weak valve springs
On a cold start where there is not enough oil and valve can NOT be fully closed ( due to oil build-up in engine as result of bad oil /15k miles oil change ) DME shutoff this cylinder to prevent gas to drop on catalizators
When the engine is warmed up Hydraulic valve lifters start to work normally so no fuel shutoff and no misfire
The problem is, - this is a huge job and not a common procedure here in US

This is a common issue and replacement on euro forums if your car has more than 100k miles and all the rest of repairs like plugs/ejectors/CVV/Vanos/Air leaks etc do not help

Originally Posted by champaign777

Vibration on a cold M54 engine with a misfire on one or two cylinders and a fuel shutoff is due to Hydraulic valve lifters wear / weak valve springs
On a cold start where there is not enough oil and valve can NOT be fully closed ( due to oil build-up in engine as result of bad oil /15k miles oil change ) DME shutoff this cylinder to prevent gas to drop on catalizators
When the engine is warmed up Hydraulic valve lifters start to work normally so no fuel shutoff and no misfire
The problem is, - this is a huge job and not a common procedure here in US

This is a common issue and replacement on euro forums if your car has more than 100k miles and all the rest of repairs like plugs/ejectors/CVV/Vanos/Air leaks etc do not help

What a POS engine. Seriously it's been making me more and more angry everyday. BMW really failed with this one.

/rant

My small update is that:

My car has only done 55k, and compression test hot and cold show everything to be in order. This should rule out the lifters as the reason for causing misfire is that they do not CLOSE the valve, which would have been seen in the compression test.

I swapped two of the fuel injectors around and the problem did not migrate. Not the fuel injector then.

Car has gone into the indy today to have the ECU updated and to have the electronic signals for the coils/injectors scoped.

Help-at point of no return. Cut hose to dipstick :-) I'm actually flying along and doing great! However, there appears to be a non-OEM electrical connection that doesn't have the spring clip? I can't figure out how to get it off. I got all the other ones off no problem (other than someone going crazy with zip ties in crazy places to reach). I'm ready to remove throttle bottle. but electrical box is in the way. I could probably do it with it like it is but it will be a royal pain. as an FYI, I haven't found any of that mayo yet. dipstick looks clean. Did notice that there was no dipstick gasket in place. Dipstick came out no problem and no mess at all.

The problem with the connector is that it looks like either the smaller end could come out of the bigger plastic piece, or the whole things comes out. The plastic clips are very rigid and can't tell if the push in, or you have to open them outwards. Either way is very very hard as the plastic is very hard. Once I get this connect off, I'll be flying along again. Notice the yellow circle with the normal metal clip. All the others have that and came right off. Do I remove piece in the red circle from teh piece in the blue circle? or remove the blue circle (which takes the red one with it)? and how hard/far to I squeeze or open that connector? I've tried but no luck either way. But also not sure which piece(s) come out.

Another note. While I cleaned the MAF a month ago, I did not inspect it well enough. there are major cracks in the both boots. Guess it's always good to replace if old, or you do not know the vehicle history. CCV hoses look better than boots. CCV so far looks good from outside. Will check for mayo as I get more things out--once I get this flipping connector off. :-)

You can take it out on the red connector. There are two squeeze tabs on it. It's probably brittle from the heat so it hardened up.

Thanks George16.

I'm dissapointed in the ECS tuning non-vented hose, in the the winterized kit (really). I knew it was non-oem, but they told me it was a winter kit. Guess winter mostly :-) that aside, it was not as flexible as the OEM hose. It was almost as bad the the 90 degree turn hose! serious.

Also noticed that the valve in the throttle body used to go about 2 or 3mm further than it does now. it's not vacuum I think as i had to push hard to get it close the rest of the way. Pics later. But open to ideas on what it is, if ok, and what it does not closing 100% of the way. Also there was a post about needing a T27, I didn't. Just the T25 and I did take my DISA off for ease and more working room. I can't say that I found any mayo in the CCV oro hoses. I'm going to clean the dipstick next but it too looks really good. I suspect my CCV was ok, but since I didn't know the history, it was a worthwhile venture. I'm not quite done, but taking my time, i'd say 4 hours for a first time. I probably spent an hour of that on the stupid electrical connection by the vanos. I also tried to take off teh air distribution to clean it but it wasn't budging and I didn't want to force it. I may get a new one anyone since I'll be doing more work next weekend when I replace the two boots that are cracked.

oh, since my last ICV cleaning a month ago, it still looks clean, but not shaking that inside roller like it should. I'll do more reaserch on that later. Most of the hoses I found in there looked ok. The short stub/stop at th eback of the engine is there. The CCV had an internal block/stop as well (new design I guess as others have reported). There is a small 1/8" ish looking hose that while not cracked that I can tell, it's very very fragile looking. pics later on that too. I can't remember the name of the metal vacuum disc on the ABS side of teh engine, above the front O2 sensor where others report just touching that vacuum hose and it breaks. Mine was fine and soft.

Well, off to close everything up, do VCG, oil change, then order some more parts (boots/air distribution). fun stuff.

Crap. Looked under car an found and extra o-ring. I'm hoping it's from the old hoses and breaking them off. I never did check the o-rings on the new hoses before putting them on. I only paid attention to the snapping of the going on. The hoses aren't looking, so I think it's from the old hoses. The little o-ring has a crack in it too. I doubt the new one if it fell off, would be cracked already. The bigger o-ring is for comparison. it's the old dipstick oring (which I did find inside where the dipstick goes. It was stuck in there pretty good). At first when I took the dipstick out, I didn't think there was an o-ring.