300ce - Not driven for a while - Running lumpy/Almost cutting out

[fraz]

Hi All, As per the title started the 300ce after a 9 days or more sat. It started first time and drove fine. Stopped at shop after 10 mins driving and when re-started it was running lumpy and almost cutting out - had to give it aload of revs to pull away. Drove for while and it was again lumpy at very low speed but when i got home it seemed to be ticking over ok.

So having spoken to previous owner he infrorms me that the distributor cap is a 'weakness' and may cause this? could this be the case? how do i check? i'm not very mechanical at all!

Any other possibilities? N.B i replaced the spark plugs not very long ago.

best regards fraz

 

[kid-jensen]

Fraz,

Get your idle speed controller checked....

 

[fraz]

OK tahnsk Paul will do - in your opinion is the distributor cap defintatley not likely to be the cause? again i have no idea even what function it performs - other than to distribute something ha!

 

[kid-jensen]

Yes, the Dizzy cap could cause this, but so could dozens of other faults. The idle speed controller's job is to keep the idle speed constant (doh!), and if this isn't happening it has to be worth checking.

If you're throwing parts at the problem, it's best to start with cheap ones. The Dizzy cap is pretty cheap, so may be a good place to start.

The idle speed controller is not cheap at all, which it is why it's best to check it before chucking it.

Whilst you have your hands dirty changing the Dizzy cap, change the HT leads as well. I know some perple say Mercedes parts only, but I've had no problems with the Halfords silicone leads in the past.

 

[kth286]

fraz

I do not think you actually have much of a problem.

It is because you stopped the car half-way during it's warm up period.

There is a device that helps to feed extra fuel (enrichen) a cold engine, and if you stop the engine half-way through this action, and then start it up again, it will likely cough and splutter for a while.
Whilst the engine had actually stopped the half-warm engine was actually continuing to heat up from the residual heat conducting from the hottest part of the engine to the rest of the engine.
You now start your engine for the second time and it is now hotter but the enrichment device has slightly over-fuelled the engine and it will splutter for a while until matters reach equilibrium.

I would suggest most cars with mechanical fuel injection of your vintage do that.

So, do not go messing !!!!!!!!!!!!!!!!!!!!!! especially, if as you admit, you are not mechanically minded.

 

[shirubaby]

what about vacuum tubes that control the idling...cant remember if there any but it's worth checking to see if any have perished...

 

[Telegraph-Hill]

why not reading out the failure memory from the

KE ECU unit It helps sometimes. Actualy the KE has a lot of failure points.
But all right, the electric like spark plugs, distributor cabs and fingers or leads is the first point to check. If the car stands for a while it may be good to reseat the so labeled KPR Relais which is the Krafstoffpumpen Relais or fuel relais as also the overcurrent Relais which sits next to the KPR relais and is square with a fuse on top. Everything else like the ais mass sensor unit incl poti etc has to be checked from someone who knows the KE. Otherwise it can be very expensive partwise.

Good luck and greets from Exeter,
Oliver