335i Multiple Cylinder Misfires

stashio · 05-04-2018, 05:28 AM

*I've posted this in the general site too so apologies if posting this here also is against the rules!"*

I know this is a topic that's been talked about a lot but my symptoms are slightly different so wanted to check with you lot.

The car cranks fine and doesn't misfire after start up or under gentle/normal driving. Usually it only misfires after it's been driven hard for a while either in sport or manual mode, once it starts missing I can turn the engine off/on and drive gently/normally and it will not misfire again until I put my foot down, etc...

This started a few days ago, misfire on cylinder 1. I've just bought the car and not wanting to throw money at it just yet (I've got 30 days to return it) I replaced the spark plug in cylinder 1 and swapped the coil pack with cylinder 2 - my logic being if the fault remains at cylinder 1 it has to be the injector and if the fault moves to cylinder 2 it's the coil pack.

So I took the car out for a test drive last night and drove it hard for a good 30 mins before the EML came back on - so I did the usual routine, turned the car off/on and drove home normally without any further issues. I've scanned with INPA today which now shows multiple misfires! 3 misfire codes for cylinder 2 (which is where I moved the suspect coilpack originally in cylinder 1) but now 1 misfire code for cylinder 1 and another 1 misfire code for cylinder 6 . Could a dodgy coilpack cause this behaviour? It's clearly suspect but would it cause misfires in other cylinders - like a chain reaction or something?

Normally I'd just replace all plugs and coilpacks straight away but as I say I've only had the car a few weeks so have the option of returning it to the dealer if I'm not happy with it. I love it so don't want to hand it back but I also don't want to be buying a set of injectors either.

The only other code I have (apart from multiple misfires) is P0420 for the catalyst system, it's had that since I bought the car and as it's been tuned I assume the previous owner gutted or swapped out the cat. I doubt it's related but wanted to mention it just in case.

Any advice would be appreciated! Cheers

sirleeofroy · 05-04-2018, 06:36 AM

This sounds almost exactly like the coilpack issue I had on my old Golf VR6, different brand and car I know but it would run for a bit just like you say and then get real lumpy and start spluttering. Ignition off and back on again would get me going but it was a matter of minutes before it started acting up again. I changed all my leads and plugs before figuring out it was the coilpack!!

Worth a shot I'd say.

Jet1990 · 05-04-2018, 08:56 AM

Sounds similar to an issue i had with a misfire. I would personally put the coils back where they were and then replace the one coil. Thats your cheapest option for now. BMW replaced all 6 injectors and coils under my insured warranty even though only 1 was suspected to be at fault ( apparently thats their best practice policy)

I have an injector that i bought that hasn't even covered a 100 miles if it may be of any use to you?

stashio · 05-04-2018, 12:58 PM

Cheers Jeff, sounds like a plan I'll get one and test it out.

Potentially could be up for your injector, do you want to PM me with a price?

therealdb1 · 05-04-2018, 06:34 PM

Put your sensible head on and stop what you are doing!
If you have only had the car for a short time take it back to where you purchased it from and demonstrate what it does.
If it is a dealer, even a back street one, they have to offer you some guarantee but the more you fiddle the more likely you are to invalidate it.
If you got the car from a private sale then it is caveat emptor but then I have never known a private seller to offer to take the car back within 30 days if you are not happy.
Of course, going back to the seller does not necessarily mean that you lose the car but you stand a reasonable chance of getting the problem fixed or at least a refund to help towards the cost. Not going back means the repair is out of your pocket and if you replace the parts yourself will not be guaranteed.

therealdb1 · 05-18-2018, 10:21 AM

Any update on this, OP?
It is always useful to others to offer a follow up when you ask a question.

05-04-2018, 05:28 AM	#1
stashio New Member 5 Rep 17 Posts Drives: E93 335i Convertible Join Date: Jun 2017 Location: Lancs, UK. iTrader: (0)	335i Multiple Cylinder Misfires I've posted this in the general site too so apologies if posting this here also is against the rules!" I know this is a topic that's been talked about a lot but my symptoms are slightly different so wanted to check with you lot. The car cranks fine and doesn't misfire after start up or under gentle/normal driving. Usually it only misfires after it's been driven hard for a while either in sport or manual mode, once it starts missing I can turn the engine off/on and drive gently/normally and it will not misfire again until I put my foot down, etc... This started a few days ago, misfire on cylinder 1. I've just bought the car and not wanting to throw money at it just yet (I've got 30 days to return it) I replaced the spark plug in cylinder 1 and swapped the coil pack with cylinder 2 - my logic being if the fault remains at cylinder 1 it has to be the injector and if the fault moves to cylinder 2 it's the coil pack. So I took the car out for a test drive last night and drove it hard for a good 30 mins before the EML came back on - so I did the usual routine, turned the car off/on and drove home normally without any further issues. I've scanned with INPA today which now shows multiple misfires! 3 misfire codes for cylinder 2 (which is where I moved the suspect coilpack originally in cylinder 1) but now 1 misfire code for cylinder 1 and another 1 misfire code for cylinder 6 . Could a dodgy coilpack cause this behaviour? It's clearly suspect but would it cause misfires in other cylinders - like a chain reaction or something? Normally I'd just replace all plugs and coilpacks straight away but as I say I've only had the car a few weeks so have the option of returning it to the dealer if I'm not happy with it. I love it so don't want to hand it back but I also don't want to be buying a set of injectors either. The only other code I have (apart from multiple misfires) is P0420 for the catalyst system, it's had that since I bought the car and as it's been tuned I assume the previous owner gutted or swapped out the cat. I doubt it's related but wanted to mention it just in case. Any advice would be appreciated! Cheers
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05-04-2018, 06:36 AM	#2
sirleeofroy Captain 94 Rep 660 Posts Drives: E90 330D M-Sport LCI Join Date: Aug 2017 Location: Buckinghamshire iTrader: (0) Garage List 2009 BMW 330D M-Sport [0.00]	This sounds almost exactly like the coilpack issue I had on my old Golf VR6, different brand and car I know but it would run for a bit just like you say and then get real lumpy and start spluttering. Ignition off and back on again would get me going but it was a matter of minutes before it started acting up again. I changed all my leads and plugs before figuring out it was the coilpack!! Worth a shot I'd say.
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05-04-2018, 08:56 AM	#3
Jet1990 Private First Class 17 Rep 107 Posts Drives: 330i M Sport Join Date: Feb 2016 Location: yorkshire iTrader: (0)	Sounds similar to an issue i had with a misfire. I would personally put the coils back where they were and then replace the one coil. Thats your cheapest option for now. BMW replaced all 6 injectors and coils under my insured warranty even though only 1 was suspected to be at fault ( apparently thats their best practice policy) I have an injector that i bought that hasn't even covered a 100 miles if it may be of any use to you?
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05-04-2018, 12:58 PM	#4
stashio New Member 5 Rep 17 Posts Drives: E93 335i Convertible Join Date: Jun 2017 Location: Lancs, UK. iTrader: (0)	Cheers Jeff, sounds like a plan I'll get one and test it out. Potentially could be up for your injector, do you want to PM me with a price?
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05-04-2018, 06:34 PM	#5
therealdb1 Lieutenant 106 Rep 575 Posts Drives: Graphite E93 335i Join Date: Aug 2017 Location: Norfolk UK iTrader: (0)	Put your sensible head on and stop what you are doing! If you have only had the car for a short time take it back to where you purchased it from and demonstrate what it does. If it is a dealer, even a back street one, they have to offer you some guarantee but the more you fiddle the more likely you are to invalidate it. If you got the car from a private sale then it is caveat emptor but then I have never known a private seller to offer to take the car back within 30 days if you are not happy. Of course, going back to the seller does not necessarily mean that you lose the car but you stand a reasonable chance of getting the problem fixed or at least a refund to help towards the cost. Not going back means the repair is out of your pocket and if you replace the parts yourself will not be guaranteed.
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05-18-2018, 10:21 AM	#6
therealdb1 Lieutenant 106 Rep 575 Posts Drives: Graphite E93 335i Join Date: Aug 2017 Location: Norfolk UK iTrader: (0)	Any update on this, OP? It is always useful to others to offer a follow up when you ask a question.
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