Engine Judder when warm BMW330i
Discussion
Specifically:
BMW330i. engine juddering - only after 7/8 miles (engine warm). Mpg goes through floor when Juddering and high petrol use. Intermittent even when warm.
Just around the first time I noticed the problem I got faults "Catalytic convertor at bank1 and bank2 below threshold". However I'm thinking this was a symptom rather than cause as the code was cleared and has not returned with over 600 miles driving + 2 cats going simultaneously. Now no codes are being thrown up, The car as 247k miles and have now bough a new car so I'm not looking to spend £1000s trying to sort this,
I'm going to check my ignition coils but I'm doubtful as no misfire codes
I'm going to replace the MAF sensor albeit with a used bosch one - yes I know, but figured better then cheap chinese effort and generally find used parts to be okay. + it's £18 and not £300
Already changed one upstream lamda sensor, but again no codes anyway
Considering a fuel filter change
Any other likely causes? please consider the specifics of the problem?
Many thanks
BMW330i. engine juddering - only after 7/8 miles (engine warm). Mpg goes through floor when Juddering and high petrol use. Intermittent even when warm.
Just around the first time I noticed the problem I got faults "Catalytic convertor at bank1 and bank2 below threshold". However I'm thinking this was a symptom rather than cause as the code was cleared and has not returned with over 600 miles driving + 2 cats going simultaneously. Now no codes are being thrown up, The car as 247k miles and have now bough a new car so I'm not looking to spend £1000s trying to sort this,
I'm going to check my ignition coils but I'm doubtful as no misfire codes
I'm going to replace the MAF sensor albeit with a used bosch one - yes I know, but figured better then cheap chinese effort and generally find used parts to be okay. + it's £18 and not £300
Already changed one upstream lamda sensor, but again no codes anyway
Considering a fuel filter change
Any other likely causes? please consider the specifics of the problem?
Many thanks
If that was me, I'd try to work out whether the amount of fuel going in was changing when the problem happens. Fuel pressure and injector duration are the easiest ways to check that - both relatively simple to monitor with inexpensive equipment.
If you aren't up for that type of investigation then the alternative is likely to be paying somebody else to do it - which seems unlikely to be cost effective under the circumstances.
If you aren't up for that type of investigation then the alternative is likely to be paying somebody else to do it - which seems unlikely to be cost effective under the circumstances.
When my 530i did this it was the camshaft position sensors breaking down. did the same thing, juddering/stumbling when warm, no codes. Assuming yours is an E46 it's the same engine (M54b30). I got lucky and found a pair of new BMW ones on ebay but supposedly the Febi ones are OEM Seimens sensors with the logos ground off. Easy job to change as they are right on the front of the engine at the top.
Edited by lufbramatt on Wednesday 26th February 09:11
Might have been done before my ownership. No open recalls on my car. It was recalled for the wiring issue couple years back. A problem that could lead to failure of the aircon fan. My aircon fan had just failed but of course they decided it was unrelated and wanted £120 just to "have a look". Changed it myself £17 and 15 mins work.
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