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Discussion Starter #1 (Edited)
Mr car has started having electrical issues recently. The fans pulse as they blow, sometimes the car sounds like it's struggling to turn over, iDrive has crashed a couple of times, and gear changes are lumpy (full gear box rebuild 2 years ago so don't think think that's the problem). Today the engine nearly stalled and the headlights went out while reversing.

From what I've read it could be the alternator/voltage regulator - any way to check which? I used Carly and the numbers seem plausible (see screenshot - taken while idling after cold start) - although the battery charge level seems low - could it just be that I need to leave the battery on charge overnight?

If I charge the battery I have a CTEK charger - is it safe to run a recondition cycle through the terminals under the bonnet with the battery connected to the car? Do I need to leave the bootlid up to vent any gasses? (I have an AGM battery).
 

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Low voltage on the battery will make the car run very bad, & get the warning message to pull over. Try & put a good charge on the battery, to rule out if it might be the battery? If the engine starts to run better, then you can focus on the battery. The tale, tale warning of a low battery is usually noted by hearing the CD/ Nav player to click during startup. If you are hearing this when starting cold, the battery is a good place to start.
 

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You can safely use a Ctek to recondition an AGM so long as it has the option, you'll need to look in your manual for it. I've never needed to lift the bootlid when charging mine, that being said I've not reconditioned my AGM which does take longer.
Here's a pic with the option from my manual but this is an MXS 5.0 and I don't know if yours is the same model.

 

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Michael
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I have the CTek msx7000, which has a snowflake setting for charging at low temps, you also use this setting to charge AGM batteries. Anyone with a low use/journey E63/64 will charge their battery once twice a month to keep the battery at optimum. You can get all kinds of connectors to go with your CTek that will make connection very easy, whether in the boot or from under the bonnet, With my F12 I have a set up under the bonnet to make connecting very easy and still close the doors etc. Actually doing it this way reduces the potential for a connection spark at the terminals.
Finally once the alternator has been stressed continuously due to poor battery strength I feel that this has a knock on effect across a number of components especially the IVM module. My conclusion from reading the thousands of posts on this problem.
 

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Discussion Starter #5
Thanks guys. Last night I did a regular (not recondition) charge with my ctek overnight, then went out for a spin today. The fan was blowing smoothly and the car seemed to run a little better (slightly less lumpy gear changes) however the voltage in Carly has dropped from 14.22 to 13.06. When shifting into reverse the blower dipped temporarily but came back.

Once or twice the voltage from AD converter fluctuated wildly (down to 8.0 at one point). This makes me think perhaps it***8217;s a bad voltage regulator. Looking at the cost I can see £125 for a voltage regulator (new, from eBay) so I might start with that.
 

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Good god they've gone up, the last time I bought one it was about £30 for a brand new valeo regulator from flea bay.
 

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Below is a link to the Valeo VR, at 38.00. The voltage regulator will cause the Dynamic Drive warning to go off after 20 minutes of driving, then the voltage will surge higher than 16 volts. At that point the modules go into self protect mode, shutting down systems on the car. If you are not seeing this, I would not think the VR is the problem. If you have some oil leaks on the drivers side of the engine, the alternator might be getting oil in it, causing the voltage to dip.

https://www.ebay.com/itm/BMW-545i-6...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649
 

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Discussion Starter #8
Thanks, although I***8217;m in the UK - useful to have a picture of the right thing. So i***8217;ve ordered the voltage regulator and for good measure a remanufactured alternator as the old one will have to come off so thought I may as well (cost £160).

The car has today started almost stalling at times, also the steering feels ***8216;weird***8217; and finally when pulling up I got an ABS error on the iDrive.
 

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Do not put a re-manufactured alternator on the car, as they are not rebuilt with the proper components. If you want to change the alternator, buy a Valeo off of EBAY for 300.00. There have been to many problems with rebuilt alternators in the past, causing all kinds of electrical problems on the car. Here is an example of a new alternator, make sure to read the fine print to make sure it is like new. There are some sellers that will do this.

https://www.ebay.com/itm/Genuine-OE...752165?hash=item51ee343e25:g:KmEAAOSwHsRYEGFr
 

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Agreed, don't go re-manufactured as the cost saving just isn't worth it in the long run, least ways, not with these cars.
 

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Seems my 2005 645Ci battery may be shot again.

What kind of life range might I expect. Car is a daily driver but only short trips
around town, under 10 miles.


Headed to the battery shop to have charging system evaluated.

Any tips or warnings since this is a battery only shop?
 

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Seems my 2005 645Ci battery may be shot again.

What kind of life range might I expect. Car is a daily driver but only short trips
around town, under 10 miles.


Headed to the battery shop to have charging system evaluated.

Any tips or warnings since this is a battery only shop?
 

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Michael
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The answer to your problem is very simple, buy a Ctek charger and trickle charge your battery once per week/fortnight. That kind of useage will never let the battery get back to full charge. There are hundreds of threads that will tell you exactly the same thing
 

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Oil on the alternator?

Have you visually checked the alternator for any signs of oil leaking onto it?

I had to replace my alternator last year after the infamous alternator bracket gasket had absolutely flooded the damn thing with oil.

Annoyingly, I may have to do the same thing again this year as the valve cover and upper timing cover gaskets have been leaking onto it (I'm in the throws of fixing them at the moment).

Anyway, I digress... The car exhibits all manner of gremlins when the alternator isn't happy. I seem to remember that there were various errors logged regarding inconsistent voltage although I can't remember the codes or the exact terminology. Active Steering, dynamic drive & ABS were the first systems to start shutting down.

Later issues were that iDrive kept rebooting and finally iDrive (and all dash lighting) would flash on and off. ...and I found myself in one of the shiny new refuge areas in the 'smart motorway' section of the M3.
 
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