1989 300SE Cuts out after a 10 min idle

[Mikesmerc]

Hello all, my 89 300SE has been unused for a month or so, I started it up the other day and left it idle, when I returned 10 min later it had cut out and refused to start. The same happed today except it did reluctantly restart but started to missfire 1 min later and cut out a minute later. The only thing I noticed was a buzzing sound coming from the ECU. Any ideas guys?

 

[malcolm E53 AMG]

Very likely condensation in the distributor cap my 88 reg 300TE suffered from this, car would restart if left for 20mins or so. The condensation leads to tracking of the spark across hairline cracks in the distributor cap - new cap and rotor arm should solve the problem. Assuming if course the car hasn’t got electronic ignition which I think came in around that time with the facelift

 

[Mikesmerc]

Very likely condensation in the distributor cap my 88 reg 300TE suffered from this, car would restart if left for 20mins or so. The condensation leads to tracking of the spark across hairline cracks in the distributor cap - new cap and rotor arm should solve the problem. Assuming if course the car hasn’t got electronic ignition which I think came in around that time with the facelift

Thanks Malcolm, pretty sure it has an electronic ignition, will whip the cap off for a look.

 

[DREAMER NO2]

Mike you have more information in your profile, than you have in your post .So what type of engine are we supposed to guess that you have ?

 

[mattkh]

Any ideas guys?

Water in the fuel?

 

[discoking]

I'll second the dizzy cap and rotor arm. Starts fine, gets lumpier as it warms up and then dies and wont start until cold again. I have had this happen on every pre-92 merc I've had. I've just replaced the dizzy cap and rotor on my new 500sel as a preventitive measure cos I know it will happen at some point( if still on the original dizzy cap and rotor).

 

[DREAMER NO2]

I tell so many that if the HT side is not up to scratch ,,to expect lots of problems.So before any other work is carried out,, it is best to replace the plugs.. distributor cap. rotor arm,,and HT leads if you have not already done so . These are not a cheap items neither is the Mercedes that you own.... 95% of all problems are electrical . And also clean the earth points and fuses .

 

[Mikesmerc]

Mike you have more information in your profile, than you have in your post .So what type of engine are we supposed to guess that you have ?

I apologise , but are there variant engine models of a 1989 300SE?

 

[Mikesmerc]

Tried removing the dizzy cap the other day, the bottom bolt tortured me , almost impossible access. will try again over the holidays. Thanks for the help guys

 

[DREAMER NO2]

So as it stand you dont know what engine you have in your car ? So now without knowing then its hard for us to help you.Is it like this one M103