W210 Alternator Woes

[Foolish]

I hate to fire into my first post with a problem, but someone may be able to help.

I have a 2001 E320CDI estate which has covered 152k. I bought it about 3 months ago and due to my work it can spend a couple of weeks at a time without use. When the cold snap occured, I left the side lights on over a weekend totally flattening the battery. I started it using a jump pack but the alternator warning light came on, the alternator was producing voltage but it wasnt charging the battery. I found a wiring diagram which shows a 200amp fuse so as a temporary measure I hard wired the alternator to the battery but when I came to use it this evening I got the alternator warning light again and the alternator wasnt producing voltage.

Any ideas? I understand the alternator is a clutched unit designed to charge on demand?

It also seemed that I have the dreaded EGR fault as I get a sluggish response plus lots of black smoke upto 2.5k rpm then boost kicks in and its fine. After a couple of minutes it goes into limp home..... Dont know if they could be related?

 

[Foolish]

Any ideas? Any help would be much appreciated.

 

[allias]

Since you hard wired your alt, there is a big chance you destroed your battery or damaged alternator. To give you some heads up alternator for 230CDI is for about £500-600 - dealer sells them at ~£1200. And yes they are about 120Amp on current.

 

[BlackC55]

What voltage are you getting?

Should be 14.4v when running

 

[MPK]

My alternator went on my E320CDI 2002 ( w210 ) last summer.

MB had no stock in country - Special order from Germany at the time.
Cant remember price...

Researched web and found this place in Luton. ( £190 exchange )
Got it same day, walk in and fitted it that evening.

All went well - No complaints.

e-mail [email protected]
website Abbco Auto Electrics

 

[Foolish]

The battery is fine and whilst it was hard wired I tried to minimise the current draw - no heated screen, blowers on max etc.... the radio wouldnt power up after the battery went flat intially either.

How does the alternator clutch operate, does it take a signal from the ecu? If it is knackered i'll get it reconditioned. Cheers for the link.

If it wasnt for the problems it would be a great car!

 

[BlackC55]

The clutch is a one way pulley, It turns one way but not the other. It has no electrical connection.

 

[tagnut]

You need to determine what voltage your alternator is producing. As mentioned above it should be 14.4V. You can also test whether or not your battery is holding it's charge by measuring the voltage immediately after charging and then some time after to check for voltage drop.

I recently had both alternator and battery go in my W211. Wasn't cheap to fix....

 

[Frankie]

I think this has answered my flat battery issue. Took it for a run, after and with the engine off it was showing 12.2v,with it running I got 13.7.

 

[Foolish]

The voltage was up in the 13-14v range at idle, i'll pull the alternator off and check the brushes. The only things that wear out on alternators are the brush/regulator assy and the bearings and since theres no rumbling I assume theyre fine.

The brush/regulator assy is an off the shelf part from bosch so shouldnt be too costly.

 

[Dunhamkid]

Are you sure it is a Bosch alternator, might be a Delphi? It should also be water cooled!!

 

[Foolish]

A little belated but still worth an update. The main 200amp fuse under the positive starter post in the engine bay had blown, replaced that and its sorted.

Cleaned out the egr, intake manifold and replaced the intake motor and she flies, without and soot and returns 36-44mpg.