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Prior to yesterday, my vehicle was functioning properly. There are 146,00 miles on this N43 320i.
This morning when I turned it on, I noticed a lumpy ride and the engine light was on; I assumed it was due to a leaking injector, but there was an overwhelming smell of petrol and it wouldn't clear up even at higher revs.
After a brief five-minute commute to work, I noticed a lot of white? I have never experienced anything like this before; I can smell petrol when gently accelerating, the engine runs fairly rough and there is smoke coming from the exhaust.
Has the engine died? It is common practice to turn off injectors when they fail.
I can quickly take a break from my work and check it out later because I have a basic fault code reader with me.
It might be the head gasket, fuelling system, injectors, lambda sensors, or something else entirely.
Thank you for your feedback.
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Assist me! N43 320i, unexpectedly rough running, strong petrol odour, white smoke
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AndrewGuidon67
- Posts: 67
- Joined: Mon Feb 02, 2026 8:44 pm
Unburned petrol is indicated by white smoke.
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EvestineBeetle
- Posts: 46
- Joined: Mon Feb 02, 2026 9:03 pm
Much obliged.
Nothing seems to have gone wrong under the hood, and the oil filler cap is spotless.
These codes were obtained by means of my basic fault code reader:
"Misfire cylinder 4" (P0304), "Nox sensor" (P122F), and "Bank 2 post cat fuel trim too rich" (P2099) are common or previous codes.
For these engines, I know that bank 1 consists of cylinders 1 and 4. The incorrect cylinder might be assigned the misfire codes at times.
Upon reflection, I changed the injector in cylinder 4 to a new BMW/VDO unit in 2022. It was only last year that a new Vitesco injector for Cylinder 1 was installed.
This level of overfueling should make it easy to identify which cylinder is flooding by simply pulling the plugs. Usually it pours down here tonight, but I was thinking I'd grab my tools and work on the work parking lot instead.
Nothing seems to have gone wrong under the hood, and the oil filler cap is spotless.
These codes were obtained by means of my basic fault code reader:
"Misfire cylinder 4" (P0304), "Nox sensor" (P122F), and "Bank 2 post cat fuel trim too rich" (P2099) are common or previous codes.
For these engines, I know that bank 1 consists of cylinders 1 and 4. The incorrect cylinder might be assigned the misfire codes at times.
Upon reflection, I changed the injector in cylinder 4 to a new BMW/VDO unit in 2022. It was only last year that a new Vitesco injector for Cylinder 1 was installed.
This level of overfueling should make it easy to identify which cylinder is flooding by simply pulling the plugs. Usually it pours down here tonight, but I was thinking I'd grab my tools and work on the work parking lot instead.
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AndrewGuidon67
- Posts: 67
- Joined: Mon Feb 02, 2026 8:44 pm
If sniffing the plug doesn't work, try a leak off test on the injectors.
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EvestineBeetle
- Posts: 46
- Joined: Mon Feb 02, 2026 9:03 pm
Do you need a special kit or testing equipment for that?
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AndrewGuidon67
- Posts: 67
- Joined: Mon Feb 02, 2026 8:44 pm
As soon as you pull the plugs, you'll be able to tell which one is stuck open if the n43 is dumping that much fuel.
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AndrewGuidon67
- Posts: 67
- Joined: Mon Feb 02, 2026 8:44 pm
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EvestineBeetle
- Posts: 46
- Joined: Mon Feb 02, 2026 9:03 pm
Hello there.
The car was recovered and I was able to get it home.
There will be thick clouds of white smoke one second and smooth, clean revving the next.
Because it lacked power, the recovery guy was unable to drive it up the ramps and had to be winched up.
I double-checked the fault codes and they now indicate a misfire on both cylinders 2 and 4.
There was no fuel odour when I removed plugs 1 and 4, which were black and dry.
I had to put everything off until tomorrow because the weather turned bad.
The car was recovered and I was able to get it home.
There will be thick clouds of white smoke one second and smooth, clean revving the next.
Because it lacked power, the recovery guy was unable to drive it up the ramps and had to be winched up.
I double-checked the fault codes and they now indicate a misfire on both cylinders 2 and 4.
There was no fuel odour when I removed plugs 1 and 4, which were black and dry.
I had to put everything off until tomorrow because the weather turned bad.