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Discussion Starter · #1 ·
2003, 520iSE petrol with 50k on the clock. The I-drive reported an engine fault – drive at reduced speed to avoid damage to the catalytic converter. BMW could not look at it straight away so I removed each spark plug to check. One of the six seemed wet. After a clean it was still the same. Managed to do a OBD diagnostic on a laptop and it said cylinder 5 misfiring. I replaced the spark plugs (under £15, I can’t image what BMW would have charged!) with no difference. Next step was to change the coil pencil since 3 of the six had been replaced with Bosch equivalents at some point. Misfiring problem cured. Now looking at the rev needle it seems to sometimes drop approx 50 revs every second or so even when the engine is warm. Should I also change the remaining 2 factory fitted coil packs or is something else probably wrong? Also starting the car anytime warm or cold with the head lights on, the light dims to almost off but the battery has never lost power. Could this be an issue or is this normal? Cheers.
 

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2003, 520iSE petrol with 50k on the clock. The I-drive reported an engine fault – drive at reduced speed to avoid damage to the catalytic converter. BMW could not look at it straight away so I removed each spark plug to check. One of the six seemed wet. After a clean it was still the same. Managed to do a OBD diagnostic on a laptop and it said cylinder 5 misfiring. I replaced the spark plugs (under £15, I can’t image what BMW would have charged!) with no difference. Next step was to change the coil pencil since 3 of the six had been replaced with Bosch equivalents at some point. Misfiring problem cured. Now looking at the rev needle it seems to sometimes drop approx 50 revs every second or so even when the engine is warm. Should I also change the remaining 2 factory fitted coil packs or is something else probably wrong? Also starting the car anytime warm or cold with the head lights on, the light dims to almost off but the battery has never lost power. Could this be an issue or is this normal? Cheers.
Hi

I would replace the coil packs as a matter of course and see if that sorts the issue.
Then rescan the fault codes if the issue is still there.

Does the car start straight away even with the lights on?

Im not sure if BMW have built in a safety mechanism to dim lights to give full power to the battery, hoopefully a similar age 5 series owner will know.

If they havent, I would say to check the output at the battery with engine running and all ancilleries switched off, and then test it with all headlights on full, air con on etc

There is a recommended voltage that musty be attained in both conditions. If the battery output doesnt meet it, the alternator or battery are on their way out.
 

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Discussion Starter · #3 ·
The car starts first time but make a slight clatter when it's switched off. I have checked the indicator on the battery; it's green full of charge. Well, reading up on the web the original coils named 'bremi' are prone to failure so I will be replacing these. I will post the results. Thanks again.
 

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Discussion Starter · #5 ·
Replaced all 6 coil pencils and fault occured after 6 weeks

Brand new coil pencils fitted and 3 times in the last 6 weeks the engine mis-fired when starting from cold. This time DTC codes were obtained as follows:

P3242

Pending:
P0300
P0301
P0303
P0304
P0306

I know the 030X codes are for cylinder misfires but don't know what P3242 is. Can some one help? Also powering off the engine rattles but drives perfectly.
 

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Will be one of the ign coils if yo no which one replace it. If misfire on certain cyl DME will stop fuel to that cyl. Also when coil replaced will need to clear fault in dme, as DME will still stop fuel to that cyl untill cleared, so will still misfire until cleared.
,
 

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You will be much better getting the fault codes read using a BMW specific scanner as there may well be more codes that the EOBD scanner isn't picking up.



Also I may as well ask, have you lost any coolant?
 

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Discussion Starter · #8 ·
You will be much better getting the fault codes read using a BMW specific scanner as there may well be more codes that the EOBD scanner isn't picking up.

Also I may as well ask, have you lost any coolant?
After the codes were obtained the car was powered off. Checking the codes after afew hours with the car off seems to have cleared the fault and codes. No coolant has been lost. Seems to be running fine for the last 1000 miles. Using proscan tool + laptop and the handheld scanner always resulted in the same codes. This is doing my head in!
 
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