Alternator Overcharging

[bhopko]

Hi everyone, had an issue with no charging on a 2.0 cdti. Have changed the regulator and I am now getting 17v at idle. Any ideas please?

[Ducati750cc]

Originally Posted by bhopko

Hi everyone, had an issue with no charging on a 2.0 cdti. Have changed the regulator and I am now getting 17v at idle. Any ideas please?

Is that at the battery terminals ?

[bhopko]

Originally Posted by Ducati750cc

Is that at the battery terminals ?

Yeah and the abs light comes on aswell

[Ducati750cc]

Originally Posted by bhopko

Yeah and the abs light comes on aswell

It looks like you have a dodgy reg,was it a brand new one ?


It should never go over around 14.8v with a fully charged battery connected, especially at tickover speed.



Why I asked if it did this at the battery and was connected to the battery was because an output test can also be done at the alternator, but if there wasn't a battery in circuit the voltage can rise to 50v and a lot more depending on revs.


Was the reg exactly the same as the old one, everything connected correctly ??


Since rebuilding the alt, has it been jump started, if so were the leads connected reverse polarity even for a second, or the battery leads connected the wrong way round, I know you would struggle doing the latter but these are the type of things that can cook the reg almost instantly?


Whatever you do don't be tempted to run it any more, especially blipping the throttle, the battery can stand 17+v for a short while but it will eventually get cooked, the big danger with over voltage is that though all the various electronics, ECU's etc have over voltage protection to a degree it isn't 100% and anyone of them are susceptible to being damaged.


Edit, I forgot to ask, did you know there are two different regulators, a two pin one and a three pin one ?

[Lee T]

I had a similar issue a few years ago, 2 new regulators, still same problem. found a small piece of one of the cooling fins had broken away and fallen into the casing. Worth a check, plus there are 2 different regulators for the diesel alternator.

[COLVERT]

Change that regulator ASAP or you can damage other car electrics that can't take that sort of pressure.---

[bhopko]

HI everyone,

Thanks for your responses, yup brand new regulator and all hooked up correctly. Spoke with DMGRS and they are very kindly sending out another one. Hopefully just a duff one and can get her back on the road ASAP, having to drive a 307 at the minute and just want to get the MG back on the road.

[COLVERT]

Originally Posted by bhopko

HI everyone,

Thanks for your responses, yup brand new regulator and all hooked up correctly. Spoke with DMGRS and they are very kindly sending out another one. Hopefully just a duff one and can get her back on the road ASAP, having to drive a 307 at the minute and just want to get the MG back on the road.

Fixed it yet ---

[bhopko]

FINALLY

Replacement regulator on and 14v. I am now a happy man. MOT this morning aswell and she passed. All in all an absolute result.