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-   -   Single misfire cylinder 5 (http://forum.e46fanatics.com/showthread.php?t=921544)

rfbmwfan 05-13-2012 09:02 PM

Single misfire cylinder 5
 
Hey guys, I'm stumped on this. Out of the blue on my way home the other night, car starts missing. Next day I switch coil packs, plugs, fuel injectors, and no matter what the miss stays on cylinder 5. So I hook up my bmw software to diagnose. Im getting DME code 1F ignition activation, along with p0305. The miss only starts when the car is warmed up and running for a while.

When I clear the code, the car runs fine for about a minute, then starts missing again.
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albarran9 05-13-2012 10:19 PM

Have you tried cleaning/checking your ICV, DISA, and MAF? Do you see any smoke? Before you go on a wild goose chase spending money trying to fix it, get a compression test done. I had a similar issue with cyl 5 a while back. My CCV was starting to go bad so it was throwing oil into the cylinder and causing misfires. Then it finally blew the diaphragm in the separator and I had it change and problem solved.

rfbmwfan 05-13-2012 11:37 PM

About 1000 miles ago, I did ccv system, intake manifold gasket, and replaced all the vacuum lines. Disa was fine, icv was as well. It just started about 30 miles ago.

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rfbmwfan 05-15-2012 11:15 PM

Bump

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jasonbimmer 05-15-2012 11:17 PM

swap coils
inspect spark plug
compression test

rfbmwfan 05-15-2012 11:31 PM

Read the post. Already done all that. Compression is 120 in all cylinders.
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jasonbimmer 05-15-2012 11:32 PM

Quote:

Originally Posted by rfbmwfan (Post 14397824)
Read the post. Already done all that. Compression is 120 in all cylinders.
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hummmm.

SeanC 05-15-2012 11:36 PM

Interestingly enough, I had a single misfire code on that same cylinder. Had to replace the fuel pump, and no more misfires.

Mango 05-15-2012 11:37 PM

someone here had the same problem on a single cylinder and swapping hardware didnt change a thing. he fixed it with the intake camshaft position sensor i believe.

rfbmwfan 05-15-2012 11:48 PM

No other obd2 codes other than p0305. When I connect my bmw dis software, it shows another code. DME 1F activation ignition cylinder 5. I've checked all fuses and relays. I am at wits end with this.

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MJLavelle 05-16-2012 12:22 AM

It is something of a longshot, but how old are your O2 sensors? Can you try swapping them around and see if the p0305 code changes to another cylinder? The 030x code indicates a misfire, and the last digit indicates the cylinder. If you already know that, then sorry for the explanation.
The fuel pump suggestion is not as crazy as it sounds. I found some other mentions of p030X codes and fuel pump issues. Strangely enough, the ones mentioned were p0305 and p0306. Maybe you can check the fuel pressure. Maybe recheck all of the vacuum lines, and see if anything has come loose.
I was helping another member with the same issue several months ago. He never posted a solution, and seems to have dropped off. I just sent him a PM, to see if he ever found a cause.

Edit - It almost seems like there is a fault somewhere in the wiring that triggers the coil or the injector. I don't know if that would throw other codes or not. That is just a guess on my part though.

MJLavelle 05-16-2012 12:30 AM

Was there any oil on the coil boot when you removed it from cylinder 5? Any chance that the spark plug tube seal is leaking?

rfbmwfan 05-16-2012 02:22 AM

csean, where there any other symptoms? Did it happen all the time or once the car was warmed up?

e46mango, I did replace the cam pos sensors, but they are not oem. Been problem free the last year and half.. but might have to go further into that.

mjlavelle, from the records I have, o2 sensors where replaced at the dealer around 30k. Car has 140k now. I will try to switch them tomorrow at work if it's slow enough.
No oil, valve cover was replaced less than a year ago. I also inspected all spark plugs and boots at least 20 times by now.. along with cleaning all the contacts on wires, and the DME relays, etc.

I replaced my fuel filter about 2 years ago, and fuel pressure regulator a year ago.

At this point, I've fixed and replaced everything that was needed and then some. When I did the ccv system, I replaced all vacuum lines while I had the intake off. Everything is connected right. I've checked and checked again just in case it wasn't.

Thanks for all the help and input so far guys. I'm going to get this fixed one way or another. I'll update when I can do some of your suggestions.

SeanC 05-16-2012 09:40 AM

Quote:

Originally Posted by rfbmwfan (Post 14398186)
csean, where there any other symptoms? Did it happen all the time or once the car was warmed up?

I believe it happened a few times towards the end of the fuel pump. Kinda trying to warn me. Not saying you have the same issue, but you should find out soon enough.

jdstrickland 05-16-2012 09:58 AM

Quote:

Originally Posted by rfbmwfan (Post 14389869)
Hey guys, I'm stumped on this. Out of the blue on my way home the other night, car starts missing. Next day I switch coil packs, plugs, fuel injectors, and no matter what the miss stays on cylinder 5. So I hook up my bmw software to diagnose. Im getting DME code 1F ignition activation, along with p0305. The miss only starts when the car is warmed up and running for a while.

When I clear the code, the car runs fine for about a minute, then starts missing again.
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You have a SINGLE CYLINDER MISFIRE, you have to concentrate on that single cylinder. All of the other stuff you are doing 1.) confuses the issue, and 2.) will cause global problems across all cylinders. You need to go back and look at stuff that is unique to the cylinder that is giving trouble. Swap the #5 coil with another coil AND NOTHING ELSE, and see if the problem follows or not, if the problem follows then continue looking at the coil. Do not introduce new parts, and ESPECIALLY do not introduce used parts, because if the new part is no better than the onen it replaces, then you will be chasing your tail. You have no misfires on the other cylinders, so all of the other coils work. Put the currrent #5 coil someplace else and put that coil on #5. If #5 remains the problem, then look to the plug on #5, and then start looking at the injector. All of the other injectors work, so swap the injector from another cylinder into 5, and put the #5 injector into that cylinder. See if the problem stays on 5 or moves.

The idea is that you are doing 4 or 5 things at the same time, and you need to do one thing and see if the problem follows that action or stays in place. If you move the external parts -- coil, injector, plugs -- from 5 to a working cylinder, and the parts from the working cylinder to 5, and the problem remains on 5 through all of this, then you have an internal problem.

Your car has already isolated the problem to a single cylinder, there is no point in looking at stuff that covers all of the cylinders that are not having a problem.

Mango 05-16-2012 10:00 AM

JD, I think he said he swapped coils and injectors already (For some reason I think he edited that out of his original post--i don't see it anymore)

jdstrickland 05-16-2012 11:20 AM

Quote:

Originally Posted by E46Mango (Post 14398846)
JD, I think he said he swapped coils and injectors already (For some reason I think he edited that out of his original post--i don't see it anymore)

He did say that, but everybody is taking him on a ride of global problems that will hit several cylinders, if not all of them, instead of just one.

And it is not clear that he is replacing stuff or swapping it. If he's replacing stuff with more stuff that is also broken, then he's not fixing anything. If he's swapping a part with a known good part and the symptom remains the same or changes, then there is a clue. The OP talks about working on his car if there is time, as if he's working in a shop and has access to used parts that don't work any better than the parts that are already on the car.

And, he said that resetting the engine code makes the car run okay for a minute or so and then it starts to misfire again. Resetting the code has nothing to do with the engine misfiring, or not. It might take a minute for the code to come back, but the misfire is present without regard to the status of the code or the resetting of the computer. The car does not say, "oh, the computer is reset, I should run okay now," and then begin misfiring anew. The condition that makes the misfire does not go away just because the codes have been reset.

Assuming the coil and injector have been swapped and the plugs are good, and the problem remains on 5, then the diagnostic efforts have to move to stuff like a valve or piston rings, or something internal. It's time for a compression test.

Mango 05-16-2012 11:30 AM

OP have you checked the simple things like plug? what plugs do you have? maybe check fuel pressure at the rail and see if within spec.

SeanC 05-16-2012 11:33 AM

Quote:

Originally Posted by jdstrickland (Post 14399067)
He did say that, but everybody is taking him on a ride of global problems that will hit several cylinders, if not all of them, instead of just one.

That's true, but you don't simultaneously get misfires on all cylinders even when something that affects all cylinders is going bad :dunno: The cylinder in the worst shape gets hits first.

rfbmwfan 05-16-2012 11:52 AM

Quote:

Originally Posted by jdstrickland (Post 14399067)
He did say that, but everybody is taking him on a ride of global problems that will hit several cylinders, if not all of them, instead of just one.

And it is not clear that he is replacing stuff or swapping it. If he's replacing stuff with more stuff that is also broken, then he's not fixing anything. If he's swapping a part with a known good part and the symptom remains the same or changes, then there is a clue. The OP talks about working on his car if there is time, as if he's working in a shop and has access to used parts that don't work any better than the parts that are already on the car.

And, he said that resetting the engine code makes the car run okay for a minute or so and then it starts to misfire again. Resetting the code has nothing to do with the engine misfiring, or not. It might take a minute for the code to come back, but the misfire is present without regard to the status of the code or the resetting of the computer. The car does not say, "oh, the computer is reset, I should run okay now," and then begin misfiring anew. The condition that makes the misfire does not go away just because the codes have been reset.

Assuming the coil and injector have been swapped and the plugs are good, and the problem remains on 5, then the diagnostic efforts have to move to stuff like a valve or piston rings, or something internal. It's time for a compression test.

I do work in a shop, however I don't put used parts on my car. I did mention that I used aftermarket cam position sensors (no trouble the last 2 years since installed though).

Coil and injector have been swapped, all plugs look good, compression test resulted in 120 across all cylinders.

The car runs perfectly fine with no misses until warmed up to normal operating temp.

I've combed through wiring to make sure there are no tears or fraying of wires, cleaned contacts, checked fuses and relays. Checked for vacuum leaks with a smoker.

e46mango, I have the bosch plugs installed, it was an oem part number I got for them. Had them installed since last year when I did my valve cover gasket.

Not sure what happened to my original post, was on my phone.. obviously I erased the whole original post and replaced it with another lol. oops.

Anyways, next on the list is a fuel pressure test.


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