E90 325i Misfiring

[mercur1al]

Anyone had a similar encounter?

Cylinder 4 and 5 misfired, i changed all spark plugs and ignition coil. Car was fine for 2 weeks or around 1000km.

Engine is N52B25, am using NGK Laser Iridium Plugs.

Currently encountering misfire again. Car is fine on cold starts, but develops a misfire in cylinder 6 once its hot. This takes approximately 5-10km of driving at regular speeds/acceleration. Once the misfire starts, it doesnt stop even if car is restarted. However, once engine is allowed to cool completely, no issues with misfiring.

Scanned the car with INPA and it tells me error code is 2E1D. Ignition time in cylinder 6 too low, spark duration too short.

Any ideas? I will be heading to the workshop, however my trusted mechanic is only open next monday onwards. Would like to see opinions before that.View attachment 59323

 

[mercur1al]

Re: E90 325i Misfiring

Just to add on, car is totally stock except for BMS Powerbox on setting 3.

 

[Meek]

Re: E90 325i Misfiring

You tried removing the powerbox first?

 

[mercur1al]

Re: E90 325i Misfiring

You tried removing the powerbox first?

Not yet, but might try that first.

 

[Red_Bean_Bun]

Re: E90 325i Misfiring

Like what Meek mentioned - disable powerbox.

Then have a look at the the rough idle stats ?

 

[mercur1al]

Re: E90 325i Misfiring

Will disable the powerbox first. Rough idle looks fine with the car doesn't misfire, all within the green zone, running from roughly -0.XXX to 1.XXX.

When it misfires, cylinder 6 and 5 are out of spec, though INPA only prompts a misfire on cylinder 6. Quite sure it is only cylinder 6 too, the last time i had a misfire on 2 cylinders and car felt much worse than it is now.

 

[Red_Bean_Bun]

Re: E90 325i Misfiring

Rough idle - the closer to 0 the better ...... double check all the coil connectors to the plugs ?

switch coils and plugs between 1 & 6 ... misfire follows ?

Will disable the powerbox first. Rough idle looks fine with the car doesn't misfire, all within the green zone, running from roughly -0.XXX to 1.XXX.

When it misfires, cylinder 6 and 5 are out of spec, though INPA only prompts a misfire on cylinder 6. Quite sure it is only cylinder 6 too, the last time i had a misfire on 2 cylinders and car felt much worse than it is now.

 

[mercur1al]

Re: E90 325i Misfiring

Haven't swopped the plug connectors yet, used to DIY the plugs on old jap sedan but with this car, less motivation and know how.

I wondered about the plug connectors too, however, correct me if im wrong please, if the plug connectors are not sitting properly, misfire should be there regardless of whether engine is warm or cold, correct?

 

[Red_Bean_Bun]

Re: E90 325i Misfiring

If it's not seated properly - you will get intermittent misfires etc .....

Haven't swopped the plug connectors yet, used to DIY the plugs on old jap sedan but with this car, less motivation and know how.

I wondered about the plug connectors too, however, correct me if im wrong please, if the plug connectors are not sitting properly, misfire should be there regardless of whether engine is warm or cold, correct?

 

[mercur1al]

Re: E90 325i Misfiring

If it's not seated properly - you will get intermittent misfires etc .....

Disabled the PBX to no avail. However, i got the car to misfire, then disabled the powerbox to test. Didn't disconnect, only put car into map 0.

Might do the other way round today, put powerbox into map 0 then try to get a misfire.

 

[Red_Bean_Bun]

Re: E90 325i Misfiring

Keep us posted bro .....

Disabled the PBX to no avail. However, i got the car to misfire, then disabled the powerbox to test. Didn't disconnect, only put car into map 0.

Might do the other way round today, put powerbox into map 0 then try to get a misfire.

 

[mercur1al]

Re: E90 325i Misfiring

Keep us posted bro .....

Car is at the workshop as we speak bro.

I didn't drive it for 3 days, last night started it and it misfired right from start.

Today morning misfired from start too. Waiting to get a diagnosis.

 

[redline15]

Re: E90 325i Misfiring

Hope it gets fixed soon without too much damage to the wallet

 

[mercur1al]

Re: E90 325i Misfiring

Weirdly, the workshop switched ignition coil #1 and #6, and the misfiring disappeared and didnt follow to cylinder #1.

We took the car out and whacked it hard, but unable to reproduce the fault too. When coil #6 was removed, it seemed to be seated properly, not loose and connector was plugged in securely as well. No visible damage to coil on naked eye inspection.

We decided to continue like that and monitor first.

Original fault came up when i was low on fuel and on reserve tank with about 50km range remaining, and it was half singapore petrol and half malaysian. No idea if it was due to low fuel or impure petrol. However, despite pumping half tank of V-Power right after the initial misfire, fault didn't go away till today when we switched the coils.

Rough running values are not fantastic, but within spec - probably to be expected of a 130k mileage engine.