When the lights go out (Battery & Engine dying)

[davidmudley12]

[ref]davidmudley12[/ref], you mentioned in another post that you've fitted a new alternator.
Has this fixed it?

With mild trepidation I fired up the girl once I’d put everything back together and stuck the alternator onto the battery and found a heathy 14v + coming through. So without wanting to speak too soon it looks like it’s fixed it, I’ll take it for a longer drive tomorrow to really test it out.

It was really fun having it in bits, though I’m pleased I’ve saved the gasket jobs for another day.

Thanks

 

[enuff_zed]

[ref]davidmudley12[/ref], you mentioned in another post that you've fitted a new alternator.
Has this fixed it?

With mild trepidation I fired up the girl once I’d put everything back together and stuck the alternator onto the battery and found a heathy 14v + coming through. So without wanting to speak too soon it looks like it’s fixed it, I’ll take it for a longer drive tomorrow to really test it out.

It was really fun having it in bits, though I’m pleased I’ve saved the gasket jobs for another day.

Thanks

Fingers crossed then. Always nice to feel you've achieved something. Start simple and work your way up and the confidence soon builds.

 

[French Connection]

281c relates to a bad alternator or the battery is not receiving a full voltage from the alternator due to a wiring issue between the alternator and the battery. Found one example of this fault on Youtube, it relates to the pyro connection + on the battery.
https://www.youtube.com/watch?v=CzNXtdP7NkQ
The connection is fired apart in the event of an accident to disconnect the main battery connection to prevent a fire starting in the event of fuel leaks, a seconday feed remains intact to maintain power to door locks so you can get out. Carry out the tests as seen in the video to see if thats the cause of your problem.

Thanks for the link Colb, I’ve found a number of videos with a number of causes so I’ve started down that general road.

Fuses check out all ok.

Checking the battery connections I find the right side of the boot area damp, water ingress from somewhere making the suspension turret wet and subsequently the carpets seem to be soaking that across a wider area.

Pulling back the carpet, the foam is wet at the bottom, and tracing the battery wiring back towards the cab I find an earth block that might be being affected by the damp. Connections look clean and grounding ok with a continuity check bug maybe the damp isn’t helping.

Looks like I’ve a few more jobs at the same time...

For the boosted battery check, by putting a battery booster in the engine bay to shortcut the wiring U.K. the boot, where do I connect the positive to? The video says alternator but I’m not so sure? And thff Ed video is too quick to see in detail. Anyone know or can provide some advice?

The weather is hampering my progress somewhat but I’ve covered the car to try and stop water ingress whilst I wait. Thanks all.

 

[French Connection]

Doh! Wrong thanks!! Thanks Enuf Zed....

 

[colb]

Use the battery cable connections under the engine bay when jump starting, the earth connection is the odd shaped bolt on top of the suspension turret, the Positive is on the engine bay bulkhead under a black plastic cover, you will see the red heavy duty cables running to it. Just lift the cover off to reveal the bolt that you put the jump start lead on. Just make sure the connections are clean and tight before jump starting. Also worth checking what voltage you are getting at that point so you can confirm the cable between the battery in the boot is ok, recent post by a member who eventually found his was damaged in the past inside the cabin area and had corroded so badl that it wasn't passing the voltage along it. He solved that by renewing the entire length.
https://www.carcarekiosk.com/video/2004_BMW_Z4_2.5i_2.5L_6_Cyl./battery/jump_start

 

[French Connection]

Thanks Colb, I found that video too. Engine off voltage front back to front is spot on, no losses. I need the engine running to determine any alternator issues or current drop in the battery cable. I have been measuring the voltage in the bay at the points you say to boost from so thanks for confirming.

 

[colb]

With engine running voltmeter on the battery terminals in the boot you should see at least 14v which will confirm the alternator is charging ok. I had an iffy alternator on my Z3 a good while back, didn't notice anything wrong for a long time only when used at night with headlights the problem showed itself as the next day battery was flat. Investigated the output from the alternator and found it was only putting out 12v, the regulator in the alternator had failed and wasn't charging the battery, use without headlights it was coping but killed it when used at night.

 

[davidmudley12]

Same story with mine, became clear that the battery wasn’t getting sufficient charge from the alternator as soon as I put a multimeter across the battery with the engine running and it was below the engine off voltage.

 

[French Connection]

David,
Have you got the NOCO GB70? People seem to either love it or hate it - seems worth one in the boot just in case?

 

[French Connection]

David,
Have you got the NOCO GB70? People seem to either love it or hate it - seems worth one in the boot just in case?

 

[French Connection]

David,
Have you got the NOCO GB70? People seem to either love it or hate it - seems worth one in the boot just in case?

I appear to be on repeat, apologies...

 

[davidmudley12]

David,
Have you got the NOCO GB70? People seem to either love it or hate it - seems worth one in the boot just in case?

I got the NOCO GB20 version, I couldn’t justify the higher price with the larger versions and the GB20 suits me well for the two times a year it will be used (and perhaps the odd camping trip to charge phones etc.).

I’m very happy with it.

 

[davidmudley12]

I gave the car a bit of a drive in the dark this evening and I’m pleased to say the lights stayed on, the engine ran beautifully and I got so overjoyed I even put he roof down.

 

[French Connection]

Excellent news for the car and thx for the info on NOCO.

 

[French Connection]

Extra oomph in the engine bay bore no fruit. Still have strong crank but no firing.
Re checking codes and I get 2737 which appears to be the key learn forgotten. Tried both keys, same.

Looks like I’ll have to get that fixed before I can get to fully diagnose the alternator charging.

 

[davidmudley12]

Extra oomph in the engine bay bore no fruit. Still have strong crank but no firing.
Re checking codes and I get 2737 which appears to be the key learn forgotten. Tried both keys, same.

I’ve heard of this before on other BMWs, it required the key and the EWS / immobiliser to be synced.

 

[colb]

It may well be that the EWS security system needs realigning with the main DME module if you have that code come up, probably due to the very low voltage your battery got to has caused it to loose its key memory details so its not recognising the keys and failing to release the starter. You need BMW Inpa or BMW Scanner diagnostics that can do the sync not at all sure any of the other readers can do that no doubt someone will be along and tell us if there are other readers that can do it.
https://www.youtube.com/watch?v=dSFvmDYvz4Y

 

[French Connection]

Agrée with you Colb that the low battery spike (whatever the cause caused it to lose the key learns.

I’m going get an Indie to do the reset and hopefully as I get a strong crank, we can get running and diagnose the one last query on alternator.

 

[French Connection]

Managed to borrow a snap on diagnosis tool rather than pay someone - it’s mega but I could never justify buying one.

I did reset the key learn, BAM, up she fired straight away.

Red light on, 12.2V at the boot, 12.3 in the engine bay. Disconnected the regulator, still 12.2/12.3V.

Conclusion, alternator’s had it. And that when you go to such a low battery voltage all sorts of weird stuff happens! At least I know what it is and can now sort it.

 

[davidmudley12]

Managed to borrow a snap on diagnosis tool rather than pay someone - it’s mega but I could never justify buying one.

I did reset the key learn, BAM, up she fired straight away.

Red light on, 12.2V at the boot, 12.3 in the engine bay. Disconnected the regulator, still 12.2/12.3V.

Conclusion, alternator’s had it. And that when you go to such a low battery voltage all sorts of weird stuff happens! At least I know what it is and can now sort it.

Pleased to hear you’ve got a way forward from here, and thankfully the alternator is an easy replacement job.