E93 335i Issue...

bezzledon · 03-31-2023, 06:55 AM

hi guys, im after a little bit of help...

ive just brought a 335i and found out it has an issue with the running side of things. when driving normally the car will run fine with no issues, but as soon as the foot goes down the car starts to struggle/judder under load.
ive had it plugged in and the following faults showed up:
29CF - combustion misfire cylinder 3
2C7B - o2 sensor after CAT
2C7C - o2 sensor 2 after CAT
2C77 - o2 sensor after CAT

ive changed the coil pack and spark plug on cylinder 3 which seemed to have resolved the issue...or so i thought, but the issue seems to come and go now. when plugging back in still getting the o2 sensor faults, so my question is will a o2 sensor cause this juddering/misfiring or am i just being stupid?
TIA.

Chappers 71 · 04-01-2023, 08:01 AM

O2 sensors help in maintaining the correct air to fuel ratios, so yes faulty o2 sensor will result in slow acceleration, hesitancy, irregular idle & rough running.
If it were me I'd put new o2 sensors in it.
Also in my experience of 35i ownership if one coil has failed the others won't be far behind so I'd also put in a new set of coils & I'd renew the plugs whilst I was in there.

int_c0m8U$tion · 04-01-2023, 11:59 AM

Can you do a log of fuel and ignition parameter data. I’d want to see your fuel pressures, timing stability, and fuel trims to start.

If the 02’s have 100k or anywhere near it then go ahead and replace as you need to for preventative maintenance anyways. Otherwise I wouldn’t recommend throwing parts at the problem based on the limited information you have, especially when the parts are going to run you 400+ for all 4 sensors.

micdev42 · 04-17-2023, 12:40 AM

bezzledon what happened with this?

bezzledon · 04-17-2023, 06:24 AM

Turns out it was the injector in the end. whilst checking over things, i noticed cylinder 3 injector was loose (from what ive read people either use a slide hammer or use a bit of force to remove them) once i managed to get the clamp bolt out....previous owner must have had a play as it was rounded off... pulled the injector out with ease, to find the locating tab had broken off and the injector was missing the decoupler ring. New injector, new seals and E10 clamp bolt purchased and installed and now seems to be running fine.
no juddering/hesitation under load.
although i still have a engine management light up going to plug it in tonight to see what this is.

03-31-2023, 06:55 AM	#1
bezzledon New Member 3 Rep 7 Posts Drives: bmw e93 335i Join Date: Mar 2023 Location: Kent (England) iTrader: (0)	E93 335i Issue... hi guys, im after a little bit of help... ive just brought a 335i and found out it has an issue with the running side of things. when driving normally the car will run fine with no issues, but as soon as the foot goes down the car starts to struggle/judder under load. ive had it plugged in and the following faults showed up: 29CF - combustion misfire cylinder 3 2C7B - o2 sensor after CAT 2C7C - o2 sensor 2 after CAT 2C77 - o2 sensor after CAT ive changed the coil pack and spark plug on cylinder 3 which seemed to have resolved the issue...or so i thought, but the issue seems to come and go now. when plugging back in still getting the o2 sensor faults, so my question is will a o2 sensor cause this juddering/misfiring or am i just being stupid? TIA.
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04-01-2023, 08:01 AM	#2
Chappers 71 Major General 5958 Rep 5,710 Posts Drives: Beige G31 540ix m sport Join Date: Feb 2016 Location: Kent, The Garden of England iTrader: (0) Garage List 2018 G31 xdrive 40i ... [7.40] 2006 E92 335i SE [9.50]	O2 sensors help in maintaining the correct air to fuel ratios, so yes faulty o2 sensor will result in slow acceleration, hesitancy, irregular idle & rough running. If it were me I'd put new o2 sensors in it. Also in my experience of 35i ownership if one coil has failed the others won't be far behind so I'd also put in a new set of coils & I'd renew the plugs whilst I was in there. __________________ G31 40ix M Sport E92 335i. E36 328is coupe E39 540i V8 6SP manual E34 3.6 M5. E34 525i sport. VW Jetta Mk2 GTI 16v. 1679cc 1967 resto-cal beetle
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04-01-2023, 11:59 AM	#3
int_c0m8U$tion New Member 6 Rep 9 Posts Drives: 2012 335is 6mt n54 Join Date: Aug 2022 Location: Virginia iTrader: (0)	Can you do a log of fuel and ignition parameter data. I’d want to see your fuel pressures, timing stability, and fuel trims to start. If the 02’s have 100k or anywhere near it then go ahead and replace as you need to for preventative maintenance anyways. Otherwise I wouldn’t recommend throwing parts at the problem based on the limited information you have, especially when the parts are going to run you 400+ for all 4 sensors.
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04-17-2023, 12:40 AM	#4
micdev42 Enlisted Member 3 Rep 38 Posts Drives: BMW E93 325i SE Join Date: Mar 2021 Location: Hereford, UK iTrader: (0)	bezzledon what happened with this?
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04-17-2023, 06:24 AM	#5
bezzledon New Member 3 Rep 7 Posts Drives: bmw e93 335i Join Date: Mar 2023 Location: Kent (England) iTrader: (0)	Turns out it was the injector in the end. whilst checking over things, i noticed cylinder 3 injector was loose (from what ive read people either use a slide hammer or use a bit of force to remove them) once i managed to get the clamp bolt out....previous owner must have had a play as it was rounded off... pulled the injector out with ease, to find the locating tab had broken off and the injector was missing the decoupler ring. New injector, new seals and E10 clamp bolt purchased and installed and now seems to be running fine. no juddering/hesitation under load. although i still have a engine management light up going to plug it in tonight to see what this is.
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