1987 300se cold start problem

[llebyat]

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

 

[mebobster]

hi, not being cheeky, when was the car last serviced? the first thing i would do would be to change spark plugs...

 

[Myros]

M103s are good at collecting crud in the

distributor cap. That would sap your spark strength and give you poor cold starting. When warmed, it wouldn't be as noticeable.
Try the whole ignition system back from the plugs ( they are easiest)

 

[SUFU71]

Hi Behind The Battery There Is A Realy With A Red Fuse It Could Be The Fuse Or The Realy
Ps:it A Silver Realy And It Could Be With 2 Fuses

 

[llebyat]

Hi All
Thanks for your replies.

The car was last serviced @ 99k by a merc garage and has now done 102k ( has full service history)

Plugs, leads, cap, rota were all replaced at the last service as it hapens according to the invoice.

Will have a look at that relay.

Someone on another forum i listed the question on has said it could be the cold start value which is under the air filter? Anyone know about this?

Thanks

 

[Myros]

the relay is the OVP relay

part no A2015403745, and will cost you £ 63.45 at your ever-loving MB dealer. I know, I just bought one, to find out my cold start trouble was the dizzy cap , £31 at GSF. ( thanks again MJTray)

If you really want the OVP, I'll pass you mine ( used once only ) for £50.

Try searching on 300 Se start, and there are a few threads that maybe helpful

 

[Young 'Un]

I find using a good quality fuel helps with cold starting. Since using Tesco 99RON my 300se hasn't had a problem starting once.