Persistent misfires on Cylinders 1, 2, and 4. Help plz :(

Maziata · 08-31-2016, 11:19 PM

(2007 335i 6MT Sedan, DCI, FMIC, CatlessDP, Procede)

Short and sweet: The other day I did a short pull onto the highway, cruised a mile or two, and all of a sudden BAM the car starts shuddering/sputtering, and just generally not being it's normal happy self. CEL came on, it idled rough, it sputtered, even occasionally revved itself up. I pulled the codes while waiting for the tow truck:

P0300 - Random/ multiple missfires
P0301 - misfire cylinder 1
P0302 - misfire cylinder 2
P0303 - misfire cylinder 3
p2414 - O2 Sensor sample error (Bank 1)
P323F - ?

So long story short, I found out the coil pack on cylinder number 2 had gone bad. I ordered all new plugs and coils as it's been about 20k since the tune up (plugs, walnut shell blasting etc). While pulling the old plugs, 1,2,3 were white/grey-ish while 4,5,6 were black. Odd. I put in the new plugs and coils, same results!

I can disconnect the first 3 coils while it idles and it has no effect on it what so ever, so obviously nothing is happening on 1,2,3. Next step, I swapped the plugs for the O2 sensors to see if the problem went to the second bank...NOPE, still nothing on 1,2,3.

I pulled the plugs from the first 3 cylinders and they appeared dry as a bone (not sure if they should be actually visibly wet from fuel), but I'm not sure where to go from here....any help is appreciated! DME Mosfets? Fuel Injectors? Seems odd that one whole bank fails at once

LQQKOUT · 09-01-2016, 05:35 AM

Do a search for burnt MOSFETS, I think that's your issue.

Maziata · 09-01-2016, 09:22 AM

Quote:

Originally Posted by LQQKOUT

Do a search for burnt MOSFETS, I think that's your issue.

What are the chances that would effect all 3 cylinders on bank 1?

feuer · 09-01-2016, 10:42 AM

Quote:

Originally Posted by Maziata

What are the chances that would effect all 3 cylinders on bank 1?

It could be all from bad O2 Sensor

V8bait · 09-01-2016, 10:49 AM

It's obviously an O2 issue, you can't just swap plugs like that. But it could be in wiring there who knows but that's the issue. You replaced everything else and when you were replacing the plugs it was obviously running lean in bank 1 and you even have a code for bank 1 O2. If it was an injector one of the plugs on 1-3 would have been significantly different than the other 2. Mosfet has about 4 more codes that throw. Jesus.

techwhiz · 09-01-2016, 01:24 PM

Quote:

Originally Posted by feuer

It could be all from bad O2 Sensor

Yep,

I had a problem like that.
O2 sensor was toast.
Replaced them both.

Illicit · 09-01-2016, 06:40 PM

The fact that it's happening on just one bank suggests to me that it's your injectors. You can replace injectors one bank at a time so if you look you probably have later series injectors in the other bank and older ones causing your misfire.

alpin3d3vil335 · 09-02-2016, 07:30 AM

02 Sensor!

Easiest way to test this is by swapping your sensors to see if the misfire moves to bank 2.

The 02 leads are a different length so you will have to re-route the shorter one in order for you to make the connection.

jwebb335xi · 09-02-2016, 08:22 AM

Quote:

Originally Posted by techwhiz

Quote:

Originally Posted by feuer

It could be all from bad O2 Sensor

Yep,

I had a problem like that.
O2 sensor was toast.
Replaced them both.

The replacement looks simple enough; why not start there!!

feuer · 09-02-2016, 08:27 AM

Quote:

Originally Posted by Illicit

The fact that it's happening on just one bank suggests to me that it's your injectors. You can replace injectors one bank at a time so if you look you probably have later series injectors in the other bank and older ones causing your misfire.

uh...no! injectors CAN be mixed and matched.

bruno-dsm · 01-09-2020, 11:01 PM

Same issue, with an P105A error...
I already checked the burned mosfet on ECU... in the next week I pretend to replace it, but I'm not sure if will be enough, maybe the O2 sensor has gone..

magsmagsmags · 01-10-2020, 03:49 AM

Exact same codes and issues for me previously was caused by pre-cat O2 sensors. I replaced them both - issue gone.

Do you have MHD or INPA to get some logs? When i was trouble shooting mine i could see the readings for one bank all over the place

FYI you can use the longer rear one for both banks, its the same sensor with a longer cable and for reasons no one understands, cheaper.

I bought mine from a Bosch dealer on eBay for £75 a pop

bruno-dsm · 01-10-2020, 11:57 AM

Quote:

Originally Posted by magsmagsmags

Exact same codes and issues for me previously was caused by pre-cat O2 sensors. I replaced them both - issue gone.

Do you have MHD or INPA to get some logs? When i was trouble shooting mine i could see the readings for one bank all over the place

FYI you can use the longer rear one for both banks, its the same sensor with a longer cable and for reasons no one understands, cheaper.

I bought mine from a Bosch dealer on eBay for £75 a pop

I did an customized map to my car, so I don't have MHD nor INPA, JB4...

I can't imagine how can you re-route the harness! Considering that the pre-cat sensor has almost the double lenght of harness (according http://www.bmw-etk.info/parts-catalog/prd/BMW/VT/P/E90/Lim/335i/ECE/L/N/2008/01/49544/18/18_0686)

What about the chinese O2 sensors on Ebay? anybody has already tested it? (~40$)

08-31-2016, 11:19 PM	#1
Maziata New Member 2 Rep 17 Posts Drives: 2007 335i 6MT Sedan Join Date: May 2015 Location: United States iTrader: (0)	Persistent misfires on Cylinders 1, 2, and 4. Help plz :( (2007 335i 6MT Sedan, DCI, FMIC, CatlessDP, Procede) Short and sweet: The other day I did a short pull onto the highway, cruised a mile or two, and all of a sudden BAM the car starts shuddering/sputtering, and just generally not being it's normal happy self. CEL came on, it idled rough, it sputtered, even occasionally revved itself up. I pulled the codes while waiting for the tow truck: P0300 - Random/ multiple missfires P0301 - misfire cylinder 1 P0302 - misfire cylinder 2 P0303 - misfire cylinder 3 p2414 - O2 Sensor sample error (Bank 1) P323F - ? So long story short, I found out the coil pack on cylinder number 2 had gone bad. I ordered all new plugs and coils as it's been about 20k since the tune up (plugs, walnut shell blasting etc). While pulling the old plugs, 1,2,3 were white/grey-ish while 4,5,6 were black. Odd. I put in the new plugs and coils, same results! I can disconnect the first 3 coils while it idles and it has no effect on it what so ever, so obviously nothing is happening on 1,2,3. Next step, I swapped the plugs for the O2 sensors to see if the problem went to the second bank...NOPE, still nothing on 1,2,3. I pulled the plugs from the first 3 cylinders and they appeared dry as a bone (not sure if they should be actually visibly wet from fuel), but I'm not sure where to go from here....any help is appreciated! DME Mosfets? Fuel Injectors? Seems odd that one whole bank fails at once
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09-01-2016, 05:35 AM	#2
LQQKOUT Lieutenant 102 Rep 416 Posts Drives: 335XI Join Date: Jul 2011 Location: United States iTrader: (4)	Do a search for burnt MOSFETS, I think that's your issue.
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09-01-2016, 10:49 AM	#5
V8bait Lieutenant 406 Rep 574 Posts Drives: e92 335i 6mt Join Date: Oct 2011 Location: Houston iTrader: (1)	It's obviously an O2 issue, you can't just swap plugs like that. But it could be in wiring there who knows but that's the issue. You replaced everything else and when you were replacing the plugs it was obviously running lean in bank 1 and you even have a code for bank 1 O2. If it was an injector one of the plugs on 1-3 would have been significantly different than the other 2. Mosfet has about 4 more codes that throw. Jesus.
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09-01-2016, 06:40 PM	#7
Illicit Private 11 Rep 57 Posts Drives: 335i Join Date: Jul 2013 Location: Kentucky iTrader: (0)	The fact that it's happening on just one bank suggests to me that it's your injectors. You can replace injectors one bank at a time so if you look you probably have later series injectors in the other bank and older ones causing your misfire.
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09-02-2016, 07:30 AM	#8
alpin3d3vil335 ST 5 Rep 23 Posts Drives: 09 335 sedan Join Date: Dec 2014 Location: Downey, Ca iTrader: (0)	02 Sensor! Easiest way to test this is by swapping your sensors to see if the misfire moves to bank 2. The 02 leads are a different length so you will have to re-route the shorter one in order for you to make the connection.
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01-09-2020, 11:01 PM	#11
bruno-dsm Registered 0 Rep 4 Posts Drives: 335i 2008 stg1 Join Date: Jan 2020 Location: Brazil iTrader: (0)	Same issue, with an P105A error... I already checked the burned mosfet on ECU... in the next week I pretend to replace it, but I'm not sure if will be enough, maybe the O2 sensor has gone..
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01-10-2020, 03:49 AM	#12
magsmagsmags Enlisted Member 13 Rep 47 Posts Drives: F10 M5 LCI Join Date: Jun 2019 Location: UK iTrader: (0)	Exact same codes and issues for me previously was caused by pre-cat O2 sensors. I replaced them both - issue gone. Do you have MHD or INPA to get some logs? When i was trouble shooting mine i could see the readings for one bank all over the place FYI you can use the longer rear one for both banks, its the same sensor with a longer cable and for reasons no one understands, cheaper. I bought mine from a Bosch dealer on eBay for £75 a pop
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