1987 300se cold start problem
Thread Starter
Newbie
Joined: Dec 2007
Posts: 3
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W126 300se
1987 300se cold start problem
Hi all
I have a 1987 w126 300se think M103 engine with a cold start problem which is just getting worse and worse.
The engine just turns over and over and over and then spluters into a missing start, then runs lke a dream once started. Following that the stating improves and when hot it starts as it should do.
Is there some sort of cold start sensor? I know there is a sensor on the top of the engine block at the rear which was replaced about 1000miles ago due to the car cutting out at juctions or stalling when hot which sorted that probelm, then this one has started?
Help apprecated
I have a 1987 w126 300se think M103 engine with a cold start problem which is just getting worse and worse.
The engine just turns over and over and over and then spluters into a missing start, then runs lke a dream once started. Following that the stating improves and when hot it starts as it should do.
Is there some sort of cold start sensor? I know there is a sensor on the top of the engine block at the rear which was replaced about 1000miles ago due to the car cutting out at juctions or stalling when hot which sorted that probelm, then this one has started?
Help apprecated
Junior Member
Joined: Feb 2008
Posts: 47
Likes: 6
2001 ML320, 1998 E430
I also have a similar problem with my 89 300SEL... 
I started a thread over on Mercedes Shop forums:
http://www.mercedesshop.com/shopforu...d.php?t=213705
I started a thread over on Mercedes Shop forums: http://www.mercedesshop.com/shopforu...d.php?t=213705
MBWorld Fanatic!
Joined: Mar 2007
Posts: 2,408
Likes: 3
There is a temp sensor, mine was bad on my 560SEC, and it would cause a hard cold start since it controls the "choke" or richness.
Are all other items on the cars in order, cap& rotor, wires and plugs, O2 sensor?
Also, has/have the intake manifold and the injectors been checked for vaccum leaks? The injector seals or the injectors themselves may be the cause, although the injectors are less likely since the cars run well once warm.
One thing that may be hard to diagnose is whether this is a time or temperature sensitive issue. Time would probably be a vaccum issue, temp would be a sensor, but could also be vaccum.
Are all other items on the cars in order, cap& rotor, wires and plugs, O2 sensor?
Also, has/have the intake manifold and the injectors been checked for vaccum leaks? The injector seals or the injectors themselves may be the cause, although the injectors are less likely since the cars run well once warm.
One thing that may be hard to diagnose is whether this is a time or temperature sensitive issue. Time would probably be a vaccum issue, temp would be a sensor, but could also be vaccum.
Last edited by Untertürkheim; Feb 20, 2008 at 12:26 PM.
