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Discussion Starter #1
I picked my M5 up exactly one month ago today, and it has over delivered in every way until a few days ago when it started running quite rough. SES is on, power is way down/not smooth and idle is rough. I also have what I've heard referred to as a 'blatty' exhaust note. My Peake was ordered a few weeks ago, but unfortunately I'm still waiting for ECS to ship it. Anyways, I ran up to autozone and had them pull the codes with what I believe was an Actron reader. I got the P01344 and P01345, both of which indicate a misfire on cylinder #2. My plan was to swap the #2 coil with another to see if the misfire follows it. I think my troubleshooting logic is sound, but before I get started I wanted to check with the board as you are all much more experienced than me with the S62. Am I on the right track?
 

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It makes sense based on the codes..The "blatty" exhaust with the diminished power makes me think of CPS's going south. Did the previous owner give you any idea of what had been replaced as far as plugs, etc?
 

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Just from what I learned searching, I agree that the symptoms could point to the CPS. That's what I thought it was before I got the codes. Is there any way to test the CPS? My thinking was that if I test the coils I can at least rule them out and channel efforts elsewhere; however, I'm very open to better alternatives on where to start.

Unfortunately, I don't have any records outside of the warranty work in which I see no mention of plugs, coils or a CPS. I know the records are a biggie on these cars, but it was a local one owner car in immaculate condition so I took the chance without them. I assume the local BMW dealer I purchased from just threw them all out as they do.
 

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I would replace CPS and spark plugs along with a tune up to start with a baseline of maintenance.

There is no way to know if CPS is good or bad, they gradually get bad without DME knowing it is bad unless it stopped responding within the percentage for DME.
 
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Discussion Starter #5
That sounds like a good idea. Is there a specific CPS I should be looking at, or should I just replace them all?
 

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If it was a local dealer, they should be able to tell you if there was any CPS replacement done, or at the very least scan the car for more definitive codes. A lot of guys just replace all 4 of them on a Preventative basis, the common thinking is, if 1 goes, the rest cannot be far behind
 

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Discussion Starter #7
The local dealer has printed out everything on record with BMW, so I'm guessing the PO used an indie between 65k-140k.

I ran out and picked up some spark plugs this afternoon. I'll install those tomorrow and see where it gets me. While I'm in there I'm going to go ahead and swap the #2 coil...I don't see any harm in doing it. I'll also plan on replacing all 4 CPS ASAP.

Thanks for the help, guys.
 

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The two codes specifically for #2 sound more like a coil, plug, or injector problem with that cylinder than CPS or VANOS to me. Especially as the one code indicates the misfire is so bad the DME is shutting down the injector to protect the cat. So yes, swapping coils is a good test.
As a quick supporting check, if the idle is rough, pulling the connector off the #2 coil would either have no effect on idle if the coil was bad or drop the rpm if it was good.
 

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Discussion Starter #10
That was the first thing I did. After less than 1/4 mile, the SES returned along with P01344 and P01345.
 

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before you go replacing things clear the codes and drive the car and see what codes come back. some codes might be old stored codes.
I agree except that he has "physical" symptoms already so there is certainly something going on with #2.

I suggest if you're going to replace the plugs, do that first but don't swap the coil yet. Run the car and see if it's better first. If it isn't and you get the same code(s) then swap the coil and see if it follows.
 
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DONT go out and replace a coil pack yet. My gut tells me that is wasted money. "Blatty" exhaust is a common diagnosis for Exhaust CPS and if you have the issue on cylinder #2 thats going to be the passenger side. Its a shame you dont have the Peake Reader because it would tell you EXACTLY the issue vs. random code readers.
If you cant wait for the Peake, do plugs (Can never hurt if hx is unknown) and Exhaust CPS only. If you have the extra money and want to do intake CPS, that certainly cant hurt, but definitely do both exhaust....

Good Luck
 
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I agree except that he has "physical" symptoms already so there is certainly something going on with #2.

I suggest if you're going to replace the plugs, do that first but don't swap the coil yet. Run the car and see if it's better first. If it isn't and you get the same code(s) then swap the coil and see if it follows.
I've had a misfire code in the past and gone in to limp mode. cleared the codes and everything went back to normal.

Iin the past I've chased a misfire issue with the wifes car moving coils changing plugs etc. I spent hours diagnosing and money working on it only to have it come back a year later, this time I cleared the codes and all was well.

I prefer to clear the codes and drive the car and see what happens. if it comes back right away or even a few days later then start looking at components.
 

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Just a couple of things, once the computer has shut off the fuel to cylinder 2; it will always misfire. Unplugging the #2 coil will just confirm the fuel is shut off and unless the code is cleared the fuel will remain off. Sometimes it is a very good idea to get the car warm then clear the code and start it again. If it instantly comes back it is likely the plug or coil. If it only happens on a cold start it is likely the injector.
That is all moot though because you will have to pull the plug and it will tell you what is wrong anyway. So when you do pull it take some pics of it and the others on that bank and post the pics.

When you switch the coil put it in position #4. That is the farthest away in the firing order, 1 and 2 fire next to each other so don't switch it with 1. 3 is only one away not the best but you could get away with it.
firing order:1 - 5 - 4 - 8 - 6 - 3 - 7 - 2
 

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Just a couple of things, once the computer has shut off the fuel to cylinder 2; it will always misfire. Unplugging the #2 coil will just confirm the fuel is shut off and unless the code is cleared the fuel will remain off. Sometimes it is a very good idea to get the car warm then clear the code and start it again. If it instantly comes back it is likely the plug or coil. If it only happens on a cold start it is likely the injector.
That is all moot though because you will have to pull the plug and it will tell you what is wrong anyway. So when you do pull it take some pics of it and the others on that bank and post the pics.

When you switch the coil put it in position #4. That is the farthest away in the firing order, 1 and 2 fire next to each other so don't switch it with 1. 3 is only one away not the best but you could get away with it.
firing order:1 - 5 - 4 - 8 - 6 - 3 - 7 - 2
Isn't #8 furthest away from #2? In the sequence above I count three cylinders on either side of the sequence between #2 and #8.
 

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Only if you expect him to work on both sides. That is not required for this problem. Also switching to the one that is exactly opposite is never suggested because a bad valve in 8 could appear as a misfire on 2.
 

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Discussion Starter #18
Quick update (sort of): My Peake finally arrived today and I pulled CE (Misfire during warm-up, Cyl #2) and C5 (Misfire, Cyl #2). That doesn't seem like any new information, but I thought I'd document the Peake codes on the thread for future reference. I still haven't had a chance to swap the plugs, but it will be done in the next few days. I'll report back.
 

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Discussion Starter #19
Update: I changed the plugs and there was no difference. Code cE returned very soon after I started the car. I swapped coils #2 and #4, reset the codes and fired it up. This time I got d0, Misfire during warm-up Cyl #4. At this point I'm pretty convinced that I have a bad coil. Is there any reason I should think otherwise?
 

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Update: I changed the plugs and there was no difference. Code cE returned very soon after I started the car. I swapped coils #2 and #4, reset the codes and fired it up. This time I got d0, Misfire during warm-up Cyl #4. At this point I'm pretty convinced that I have a bad coil. Is there any reason I should think otherwise?
Sounds convincing enough to me.
 
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