I got my m5 recently, and developed a misfire on cyl 3.
It only happens when cold.
It cuts out the fuel to cyl 3 to not send unburned fuel to the cat and damage it.
When Cold - engine is misfiring, you can feel it a little bit. When it warms up, it doesn't misfire anymore.
I get 002B37 fault code: Misfire with cut-out cyl 3.
I have replaced the spark plug with a new one, (i have ignition coil on order), the problem is still there, so I swapped ignition coils 3 and 4, the problem is still cyl 3. Yes only when cold - I actually let the car sit 5 hours, or the next day.
I also just got this code: 002796 Check at lower top.
So I got the compression guage out, and when i first fire it up, cyl 3 pulses up to 60 or 70 psi, then drops a little, but then pulses up to 130psi, and stays at that until I push the relief valve on the guage.
So i think the valves are being adjusted when cold and there is overlap which lets some pressure out? Any one have experience with this?
Anyway, I also swapped the ionic modules left to right. Which did not move the fault over.
I'm really starting to wonder if the wiring to the ignition coil is messed up ? I did have the ignition coil out and a spark plug in it pushed against ground and the spark was sparking, it didn't seem like a very strong spark but it was there...
It was wet, smelled with fuel. However now with the new plug, and shortly after first starting the engine(still cold/ still misfiring) the plug is dry, so the ecu cut off the fuel to the cylinder.
I find when the engine warms up, it misfires less and less, and then it runs good without any misfires.
I checked with rheingold the quality of combustion, it's not the best but there are atleast 2 other cylinders which have same readings and no misfire, or codes on those cylinders... i'm hoping it is the fuel injector, I have some on order.
Still waiting on my fuel injectors, and then finding time to replace #3...
But i fired her up today she was idling very rough, worse than usual, and i got these codes:
(CARLY)
Fault: Misfire with emissions deterioration cyl 3
Code: 2B44
Fault: Misfire with cut-out cyl 3
Code: 2B37
Fault: Motor emergency programm activated
Code: 2B57
Fault: Motor emergency programm activated
Code: 2796
After about 1 minute of this non sense I shut the engine off, and then started back up, and she was idling ok. I cleared codes and all seems well.
It's only happening for the first approx. minute when starting cold.
It's annoying me.
Anyone have any vanos valves Used but still ok that they want to sell?
I don't have any faults for vanos or vanos related components, but my values were not the best, I was thinking of trying to swap a different one in to see if this goes away. Not too happy about paying $350 for a stupid valve, x 4.
Hey Jim... So I pulled the fuel rail out like in the clip, and had my wife push start twice, i felt the fuel rail get stiff (build up pressure) and No leaking from injectors.
I'm pondering if i should put the rail back in and just give the engine a quick turn , but not allow it to start or shut off just before it does, and then see if the injector stays on then?
The rail is tight, not much slack on the fuel line, so I can't really put see thru cups under the injectors to monitor the spray...
I hooked up my laptop w/Rheigold, and I cleared codes, and went to monitor the combustion quality.
When I first fired it up, Cylinder 3 was still dropping below 0.3 (red/fail) but not all the time, randomly. I also noticed cylinder 4 do it but only a very few amount of times. Cylider 3 eventually went to 0 red and just stayed there. At this point I decided to shut the engine off, and about 15sec later I fired it up again, still monitoring and now it never went below 0.3, and the engine did not run rough anymore.
Anyway, I'm wondering if its possible my wiring to the injector or to the coil is broken, or starting to break? Or do I have a bad coil and/or injector on both cyl 3 and 4 ?
I will post a screen shot soon.
I forgot to mention, the cluster stated 6 degres celcius; much warmer than the -2deg.C or colder that i've had to start the engine in over the last few weeks.
You seemed to have checked many good things already. A thought: The secondary air injection is mounted on cylinder 3. When cold the, secondary air runs. Upon warm restart, I believe it may not. Could this be the difference? Disconnect you 2nd air hose from the injection check valve on that side and see what happens on cold start?
So i tried to fire it up this morning when cold with rheingold monitoring spark quality, i fired it up, spark quality was decent - similar to other cylinders.
It was running rough as usual.
I then went to the combustion quality and cylinder 3 was always poor and finally it got shut off and stayed at 0, ofcoarse check engine light came up.
The secondary air thing - i'm not sure where on cyl 3 it is mounted? But when i ran the car last week to do the emissions monitors setting to ready, this is the one thing that would not set as ready.
I think you are right, it only operates for the first couple of minutes when engine is cold started, after that it doesn't any longer....
anyway, i'm still not sure where the hoses are and such... i will try to do some googling.
Have you compare the compression number from other cylinders? Might be a vaccume leak somewhere. Did you see if the injecter actually pulses when first started? I had a 528 did the same thing before, I know it's not an M5, every cold start was running rough and check engine light on with #1 cyliner miss fire, and it would run fine if restarted. It turned out to be the oil separater had internal crack and cause a vaccume leak.
Oil separater is inside the intake mainifold and not changeable as it is part of the housing. Don't think secondary air injector has anything to do with the problem as it is only mounted on the outside on the cylinder3 general area. It doesn't go directly into the combustion chamber. You can try to disconect #8in the first picture to see if it helps. I would still check the gaskets around the throttle bodies, could be air leaks. And if possible, try to see if the injector actually fires when first started.
So I warmed up the car drove around town, parked it outside its warm out today around 18deg celcius.
I washed it, went in and did house work, about 5 hours later I fired it up and kept gas pedal on to keep rpms at 2000 during the "cold start", kept it there for about 30sec, I could still feel the misfiring, but not as bad and no engine light.
I then let off the gas slowly, to a idle. Did not feel any misfire at idle now.
I put her in gear and went for a drive, 15km later with mixed driving I put in the obd scanner, and she has a cyl 3 misfire registered.
On monday I will put new ignition coil on, and I will have 2 brand new injectors, I may replace that also.
However I did already swap injector with cyl 4 and coil with cyl 4 and cyl 2.
I still have this cold start misfire only on cyl 3.
Are the flaps in your throttle actuators moving in unison? The throttle body gasket check is another good one. I thought about suggesting this but you said it was a startup-only issue. And it is the idle actuator that controls this; not the throttle actuators. Move the throttle blades by hand; check for stiction and excessive resistance.
Yes its only on cold starts, and if I let it run for 30sec then shut off and restart it idles fine and no misfires.
The flaps in the throttle bodies? Yes these all move together in uniason. The throttle actuator did seem like it was tought to push on, but I took the little plunger off the throttle bodies and they moved freely.
I have not focused on throttle body gasket at all when I had the intake manifold off, maybe i should have looked for deterioration, but the individual throttle body boots comming off Intake manifold looked good and solid. I did put a small coat of oil on to help it come off next time, because it was on there really good.
I dont have ang codes for throttle bodies. I did have once on a colder morning a idle control valve code, where the engine idled rough but shortly after that went away and I havent had it happen for over 4 weeks now.
Just a quick question, just to double check... cylinder 3, which one is it? I better not have the wrong one... I did google it and as far as I know it is the 3rd from the front of car on the passenger (right) side of car. Correct?
Damn. I was hoping I was on the wring cylinder, but im not...
So I will try to disconnect the secondary air line from back pass side of Intake manifold before I fire her up.cold next. I might get a code for that but if she runs well then I will know it has something to do with that.
Otherwise I will put new injector and ignition coil on number 3, and maybe do another compression test.
Quick update; not much progress in the last two days... will get my parts on monday so i will post results after replacing some of the parts.
Anyway, Cold starts in the monring were horrible as usual, with engine light comming on, cyl 3 misfire with shut off, the usual.
However, Today I left the car in the sun and it's nice and warm out, 20 deg celcius, and after about 9 hours in the sun, i fired it up and vioala, no hesitation no rought idle, no misfire. Just loud - like its supposed to be during first couple minutes while the air pump is operational.
I feel the air pump is to blame, but why during cold starts only?
Maybe that small maf sensor on the air pump plumbing is dirty??
well, i cleaned the two MAFs and the small recirculation Maf, and no change lol
engine was already a little bit warm, when i replaced the ignition coil with a brand new one, I have to wait till the engine cools down to see if the mifire is infact solved.
Yea no luck. I swapped the coil with a brand new one. It still misfired on cyl 3, but it didn't give a engine light, code did get stored... , engine running did imrove slightly however.
I then put the other new coil i bought ( i got 2 of them) into cyl 4, and the engine warmed up a bit, and it did idle and go up in revs significantly better.
This really sounds like a stuck injector. The low compression to start is because the oil gets washed off the walls of the cyl. It then comes up as the oil is normally added to the walls. The misfire is from the cyl being flooded. Heat can play a roll in whether an injector drips.
A cheap test/maybe fix is throw a couple of bottles of injector cleaner in a tank, something like techron. At the same time use a lube in the tank also. I would use Lucas upper lube with injector cleaners at twice the rate spec'ed. A liter bottle does many tanks so don't draw a conclusion until you have put some miles on. If it works you will notice some intimidate improvement or change but it will take many liters of fuel for full results.
If there is a change just keep using the Lucas, but plan on having the injectors pulled and pro cleaned on a ultra sound cleaner. After they are cleaned you can stop using the Lucas or you can continue at half the spec'ed rate. That will prevent future problems.
I added some fuel injector cleaner a few weeks ago, not sure if techron is a substance or base of some sort, i didn't pay attention if the one i added had that or not.
I also got two new injectors, I will pull the manifold and replace #3.
I am suspicious of wiring possibly to injector?
This issue is really pissing me off....
I also pulled the oil filter last night and yea, looks like i have copper sprinkles in the oil and on filter. First thought: Great I will have to do the crank bearings.
Second thought; I did the oil change only about a month ago, not sure what kind of oil was used by previous owners, not sure if that makes a difference, but after discovering the sprinkles I put a new oil filter in and in a few weeks i will pull it off and check for sprnkles again, and if i dont' see any, then maybe i will pull the filter again a few weeks further and monitor? Or should I just buy the bearings and start preparing for the job. I will be doing it my self.
Not all injection cleaners are the same Techron is a product made by Chevron, it has a different chem structure that really works. Most products are designed for gas pre 1990. With the reduction of certain things in gas new problems were formed and take new tech to over come them. So unless you used Techron, Guaranteed to Pass by CRC or other product that contains polyetheramine you did not do much. Also with the reduction in lead and sulfur injectors really need to be lubricated when they are questionable IE the Lucas.
I am not trying to be a smarty pants here but from what you have said you have done little to help the injectors, for a problem that is bugging you it will cost you about $10 to follow my advice. Electrically failed injectors don't stick open.
If you want more proof for yourself do a fuel pressure test and see what pressure is maintained when the car is shut off. That is what I would be doing. Likely your car holds pressure when warm but as the injectors cool and all the metal shrinks they start leaking. So if you tested the pressure the next day you would have 0. You won't have full pressure even if all things are great in your car.
I have now put a brand new injector in, and a brand new ignition coil along with a 2 week old spark plug on cylinder 3.
I still have cyl 3 misfiring when cold - started it today after sitting overnight in the garage.
i was monitoring combustion quality on my rheingold software, and yes cyl 3 is below 0.3 and red. so Of coarse after a minute of idling like **** i shut it off, and restart it, and now it's fu&*ing not misfiring.
What i noticed is that cyl 8 sometimes goes into the red also - but never throws a code for misfire....
I have swapped my ionic modules already from left to right a few weeks ago, is it possible that they are Both bad ?? cyl 3 and 8 would be the same from the ionic module's point of view??
where to get a good one and not pay for it unless it solves the problem?
Ordered new ionic module... have to wait 5 days for ecs to get it, then a couple for them to ship it.
298usd... this better solve my cold start misfire on cyl 3.
Tomorrow morning on a cold engine, i will remove the ionic module, put it in the oven at 100 deg. F. and warm it up for 10min and then put it back into the car, and start the engine with a warmed up ionic module. Figured it's worth a shot.
Hopefully this resolves your issue, I've been getting a random misfire on cyl 3 as well, but it's so intermittent that I can go a week or so before the SES light comes back on. I'm starting to lean towards the ionic module too.
So while I still wait for my ionic module and hope that will solve the problem i'm having... I re -read some of the replies to my thread, and re-thinking about some engine items, i did a search about the secondary air, and came across this video showing that it can be cleaned - atleast on the v8 motor.
Is it possible to clean on our s85 motors also? perhaps i have carbon build up also?
is this where I would go about cleaning it - remove the screw (blue circle) and shove something in there to clean out carbon build up?
If i remove the whole valve, would I see anyhting in there?
I did run a test in rheingold of the recirculation system and it came up as OK., but that was already on a warm engine, I'm only having issues on a cold engine.
Also I have some screen shots of vanos and other items at idle, maybe there is something someone will notice that doesn't look right?
This is the code I keep getting in INPA:
(I have both inpa and rheingold, inpa is installed in german, so I have a hard time with it but it's quick to use)
This is the spark and combustion quality ( warm engine, didn't have a chance to capture screen shot of cold engine, i'll get it another day)
and finally, this is my vehicle. She's in really good shape for a 10 year old, has just 1 door ding, other wise she's mint.
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