[W126 Coupe] 1982 380SEC - started but won't stay charged

[Dick Spellman]

Hi Mark,

check battery resting voltage (engine off)...check battery voltage with 
engine running..then report these two readings to list

Regards,
Dick

Mark Foster wrote:

> Hi,

>

> I suspect this is an alternator issue - but I thought I better ask the

> expects in this forum. 

>

> My 380 SEC has not been running for about a year. I went out and started it

> today and after a 20 minute jump it started but I had to turn the key a

> number of times as it seemed as though it would not always catch. The

> dashboard starting lights would illuminate but there was just a click sound

> and then nothing. So I gave it a few more minutes - tried again - and this

> time it started. I gave it a few minutes running, then shut it off.

> Naturally it would not start again ( actually was surprised the old girl

> started for me in the first place) so another jump and the same scenario -

> clicks  - then finally it caught and roared to life. This time I let it run

> for half an hour  - watching all the gauges ( seemed normal ) - then went

> for a very short drive. Up and down my street - just in case ;-)

> So I finally turned it off and - guess what? Nothing! The battery seems fine

> as I had it on charge for a few days before attempting this. So, I am

> guessing the next natural trouble shooting progression would be the

> alternator? 

>

> Thoughts/comments greatly appreciated.

>

> Mark ( Vancouver - Canada )

>

>

>

> -----Original Message-----

> From: mbcoupes-bounces at mbcoupes.com [mailto:mbcoupes-bounces at mbcoupes.com]

> On Behalf Of kabed1980 at yahoo.com

> Sent: June 17, 2009 5:14 PM

> To: Mercedes Coupes Mailing Lists

> Subject: Re: [W126 Coupe] Suspect OVP relay (update)

>

> When I finally got to my 560after 7 years of sitting not running I finally

> got to u got it running bitter then new I had the run in with the alternator

> same description 

> Sent via BlackBerry from T-Mobile

>

> -----Original Message-----

> From: "Iain Gunn" <igunn at bmts.com>

>

> Date: Wed, 17 Jun 2009 19:08:54 

> To: Mercedes Coupes Mailing Lists<mbcoupes at mbcoupes.com>

> Subject: Re: [W126 Coupe] Suspect OVP relay (update)

>

>

> Here, let me tell you another one that will throw you.

> Speedometer starts bouncing all over the place, all gages start going 

> erratic, everything starts shutting down, blower motor goes on to high heat.

>

> Think you're in the "Close Encounters of the Third Kind" movie?

>

> Brushes in the alternator, or alternator.

>

> Anyone got more for the new guy?

> ----- Original Message ----- 

> From: "Afzaal Khan.M" <afzaal53 at gmail.com>

> To: "Vance Rowley" <vance.rowley at tiscali.co.uk>; "Mercedes Coupes Mailing 

> Lists" <mbcoupes at mbcoupes.com>

> Sent: Tuesday, June 16, 2009 9:04 PM

> Subject: Re: [W126 Coupe] Suspect OVP relay (update)

>

>

>   

>> Great!  fault diagnosed and  rectified.

>> mak

>>

>> On 16/06/2009, Vance Rowley <vance.rowley at tiscali.co.uk> wrote:

>>     

>>> Yes, at last, confirmed. Received my new OVP relay this morning and 

>>> before

>>> the delivery truck had driven away, I had the parcel ripped open and 

>>> fitted

>>> the relay. My thoughts as I was about to turn the ignition key was "well,

>>> here goes" But as soon as I did, I could tell that this is it, as the 

>>> engine

>>> started immediately and the ABS/ASR warning lights went out. It used to 

>>> take

>>> around 10 seconds or more of the engine turning over to start with the 

>>> old

>>> relay. The engine was very smooth and no stumble or hesitation when 

>>> revving

>>> the engine. The idle was fine also.

>>> I know that the OVP gets blamed for everything, but it looks like if you

>>> have the 4 symptoms all at the same time.

>>> 1. Takes a long time to start

>>> 2. High Idle

>>> 3. ABS/ASR warning lights remain on.

>>> 4. Rough running of the engine.

>>> Then it looks like the problem is almost certainly the OVP relay. Of 

>>> course

>>> it is possible that the fuse is just blown, but if that is OK (as mine 

>>> was)

>>> then a new OVP should be the next step.

>>>

>>> For those who want to have a go at repairing the relay, from what I have

>>> discovered along with input from this group, it looks like if you get all

>>> symptoms at the same time, then as long as the fuse, relay coil, contacts

>>> and solder joints are OK, then the most likely culprit is the diode

>>> connected between pin# 15 and the relay coil. It is unlikely that the 

>>> zener

>>> diode is the problem, as this would more likely blow the fuse if the 

>>> zener

>>> was at fault. If you get only 1 or 2 of the above symptoms, then a solder

>>> joint (or more) would be most likely.But of course when you get only 1 or

>>>       

>

>   

>>> 2

>>> of the symptoms, say for example the ABS warning light on, then it's

>>> possible the OVP is fine and that the problem could be the ABS computer

>>> itself. It's understandable that the OVP gets blamed for everything, but 

>>> is

>>> certainly the first thing to check.

>>>

>>> Thanks again to everyone who gave their input.

>>>

>>> Regards,

>>>

>>> Vance.

>>> The MB Coupes Website!

>>> W126 SEC Mailing List

>>> Postings remain property of MB Coupes, L.L.C.

>>>

>>>       

>> The MB Coupes Website!

>> W126 SEC Mailing List

>> Postings remain property of MB Coupes, L.L.C.

>>

>>     

>

> The MB Coupes Website!

> W126 SEC Mailing List

> Postings remain property of MB Coupes, L.L.C.

> The MB Coupes Website!

> W126 SEC Mailing List

> Postings remain property of MB Coupes, L.L.C.

>

> __________ NOD32 4164 (20090617) Information __________

>

> This message was checked by NOD32 antivirus system.

> http://www.eset.com

>

>

> The MB Coupes Website!

> W126 SEC Mailing List

> Postings remain property of MB Coupes, L.L.C.

>

>