M40 Died Electronically! Please Help... FIXED NOW

[Tan91]

Hi guys, Been a while only because of exams etc...

Anyways, the turd just cut out, its had a new battery this year, a BOSCH Silver and a new alternator, Drove it in the morning was fine, then a few hours later driving it back from uni, only a 5 min drive this happened:-

Stereo cuts in/out = So I turned it off and removed the face
e/w up/dwn very slowly = didnt move them

idled fine and lights where off all day except once when i just flicked them on at a red light for 2secs literally. Got home, Parked up and turned it off. Tried turning it back on...NOTHING.



My guess is that alternator has failed as it is a refurbed one from when it blew before, or maybe earth wires need replacing???

Any pointers welcomed obviously..

[Grrrmachine]

No point guessing; get a multimeter and investigate properly. They're only a fiver.

First off, confirm the battery is dead (less than 12.2V). If so, either jump or bump-start the car or use a battery charger to get it going. With the engine running, confirm that the power is now between 13.7-14.4V at idle. If it's not, it's either your alternator, the belt, or the earth terminals including the engine-to-chassis earth strap.

Run the car for 15 minutes. Stop it, check the battery level, and confirm it's around 12.6V. Leave the car for a few hours.

Come back and check the battery level. If it's dropped (12.4-12.2V) then you've either got a dying battery or a battery drain somewhere.

[Tan91]

Yeah I just finished checking all that, its the alternator, rolling around 10.95V whilst running obviously, so its a new alternator needed.

Car started fine after couple of hours, but charging was low. Just gonna get one from ECP. Was a bit funny just dieing on me like that but found the solution now...

Garage tested it for free...

Thanks though!

[bmw9818]

ive got that same issue with my m20! its intermittent though, it dies then after a few hours it starts up fine,

did you say your alternator was new?

[Tan91]

Well this is the story for the alternator....

Original up until last year then...I was installing an amp and the common mistake of letting the power cable touch the body so it surged. Got it taken in and had a refurbished model.

Now its died out, only giving 9/10V from the alternator and the batter receiving around 10.95 was the readout.

Could this have anything to do with wiring?

Also took it for a Car wash the previous time I drove it (the day before which was working fine all electrics powering up)...maybe the car wash generously cleaned the underneath and water got into the alternator?

[bmw9818]

You should have a plastic underguard, it hooks into the front valance and a couple of nylon and other bolts hold it on so the front section of the engine is sheilded from water etc,

but yeah i have a similar issue where my pipe burst and sent coolant gushing onto the alternator, prior to that it was working fine, however now seems to of come back to life, must of dried out or something!

[Tan91]

You should have a plastic underguard, it hooks into the front valance and a couple of nylon and other bolts hold it on so the front section of the engine is sheilded from water etc,

but yeah i have a similar issue where my pipe burst and sent coolant gushing onto the alternator, prior to that it was working fine, however now seems to of come back to life, must of dried out or something!

Now that dried out thing your on about made me feel better, however still could be an alternator prob as its a refurbed unit, I will see how she starts tomorrow and get it re tested and see if its up to the job, may just save my self £100, I shall resume praying

[Tan91]

Fixed! A new £130 and a new alternator sorted it out.