W124 starting issues...

MB-tex

Active Member
Joined
May 5, 2010
Messages
104
Location
Brighton UK
Car
1996 E280 estate.
Hi all

w124 estate 2.8, 5 speed, 252000 miles. It has a new starter motor and alternator and the battery is good. Twice recently the car would not start. All dash lights lit but no cranking whatsoever. On both occasions I shifted the gearlever to and fro and then back into park and it started perfectly. I am wondering if the thing that stops the car starting when it is in drive is beginning to fail. Any ideas? Would like to get to the bottom of it early so it doesn't leave me stranded...

Thanks

Tom


IMG_6490.jpeg
 

BlackC55

Authorised Forum Sponsor
SUPPORTER
Joined
Feb 8, 2007
Messages
19,957
Location
Portsmouth, Hampshire.
Car
E55K SL500 E250X2 Smart44 Brabus Track car E450Cabriolet X350 Pick up
We have just had a 124 in with a similar issue. I am not hugely technical so cant be exact but the guys replaced a switch that goes on the side of the gearbox, that tells the car which gear its in. this one we had here didn't know that it was in park so wouldn't start intermittently. Could it be the selector on yours playing up?

Natacha
 
OP
OP
MB-tex

MB-tex

Active Member
Joined
May 5, 2010
Messages
104
Location
Brighton UK
Car
1996 E280 estate.
Thanks Natacha.

I suspect you're right. If you get the chance, could you ask the guys who replaced the switch what the part is? Any further info greatly appreciated. Would like to get to the bottom of this...

Tom
 

Trickythemerc

MB Enthusiast
SUPPORTER
Joined
Feb 1, 2015
Messages
2,637
Location
South Manchester
Car
CLK 220 CDI Sport 2009
Most likely culprit would be the inhibitor switch, not sure where it is on you car but it will either be screwed into the box or be part of the selector mechanism.
 

BlackC55

Authorised Forum Sponsor
SUPPORTER
Joined
Feb 8, 2007
Messages
19,957
Location
Portsmouth, Hampshire.
Car
E55K SL500 E250X2 Smart44 Brabus Track car E450Cabriolet X350 Pick up
I have his invoice here actually as the car hasn't been collected yet. Its called a starter lock out switch on the invoice (probably goes by other names too!), it was £47.70+ vat from Merc
Natacha
 
Last edited:

markjay

MB Master
SUPPORTER
Joined
Jun 24, 2008
Messages
38,476
Location
London
Car
W204 C180 Executive SE 2013 Automatic / COMAND NTG4.7 and Morel speakers fitted by www.comand.co.uk
I believe it is called the Inhibitor Switch.

When it goes, the car thinks it's in P.

So you have all the lights on the dash but no starter.

Incidentally, and don't try this at home, but you can still start the car by briefly feeding the srarter solenoid with 12v directly from the battery and then drive the car normally (don't ask me how I know ;) ). Obvoisly you have to make sure beforehand that car is actually in P!! Bypassing failsafe features is never a good idea... ahm. But it does pin-point the issue.
 

optimusprime

MB Enthusiast
SUPPORTER
Joined
Dec 29, 2013
Messages
4,989
Location
Kidderminster Worcestershire UK
Car
Mercedes W124 260E M103
I used to think they were on the selector lever itself but apparently not .See picture its the round item to the left with the brass pins showing .And the read up is , that the part is very hard to remove room is restricted . maxresdefault.jpg
 

grober

MB Master
Joined
Jun 22, 2003
Messages
30,687
Location
Perth, Scotland
Car
W204 ESTATE
Neutral Safety Switch - Wrench Log - How I Did It
This is for the earlier type. Notice its important when mounting the switch that the gear lever is in neutral and the switch position is in the neutral [allow start position] also.
Irrc later models had a slightly different design?? just one example always best to reference your chassis no.
Mercedes R107 W123 W124 R129 W140 W210 Neutral Safety Switch OEM NEW | eBay

DECLUTCHING-START/BACK-UP-LIGHT SWITCHES,CENTRIFUGAL GOVERNOR MERCEDES W 5 A 030 (722504)
item 339

getImage.php
 
OP
OP
MB-tex

MB-tex

Active Member
Joined
May 5, 2010
Messages
104
Location
Brighton UK
Car
1996 E280 estate.
Thanks for all the replies and advice. There is a specialised automatic gearbox centre just around the corner from me. Maybe I'll have a word with them though was hoping it was one of those jobs I could do myself! But Optimusprime's words "the part is very hard to remove room is restricted" puts me off. I've almost had enough of crawling under my car (50 this year!). The 5 speed gearbox has been flakey recently - not always in the right gear and slow to change down. The automatic gearbox centre gave me a quote of £1700 for a full rebuild including new torque converter. I am at crunch point with this car...do I invest (head gasket, gearbox, rust) over the next couple of years or do I just let it go. Just passed MOT with no problems and still runs beautifully...
 

grober

MB Master
Joined
Jun 22, 2003
Messages
30,687
Location
Perth, Scotland
Car
W204 ESTATE
Transmission shifting is often dependent control inputs ----cable from throttle assembly or vacuum from manifold. thus cable adjustment or checking vacuum integrity may help resort smooth changes. What's the appearance of the fluid like. If its dark or has a burnt smell it may be a sign there's a major gearbox problem-usually its translucent red in colour.
http://www.w124performance.com/docs/mb/other/tranny_722_Mitchell.pdf
 
OP
OP
MB-tex

MB-tex

Active Member
Joined
May 5, 2010
Messages
104
Location
Brighton UK
Car
1996 E280 estate.
Thanks Graeme!

That is a great document on the 722 gearbox.

The fluid looks ok - it was changed 3 years ago. Yes, I wonder if a full overhaul of the gearbox is necessary. But it is finding someone who knows about these particular subtleties. The auto gearbox centre said their 722 expert had just retired...But these cars aren't that old and I'm sure they are not too hard to diagnose and fix?

The gearbox no longer inspires confidence and sometimes feels like it no longer knows what it is doing! Works fine most of the time though.
 

horatio

MB Enthusiast
Joined
Apr 11, 2011
Messages
1,021
Location
herts
Car
CLK, 190E
Tried john haynes in worthing? They adjusted a few bits n bobs on our 190's gearbox when I lived down that way. The early 5spd isn't quite as strong as the others (by old Merc standards - its only lasted 250,000!).
 

Users who are viewing this thread

Top Bottom