W124 300CE....Not a happy car or happy owner!

[Humair]

Hi All,

Happy new year!

Major problem, which no mechanic is giving ma straight answer on at the mo! basically the starting of the car is very poor, basically it starts only with a litle gas, and on top of that starts to choke and attempt to turn off, once it idles for a short time its fine, also the petrol conumption is getting a little high form my liking.... I have been told that this could be down to a ECU problem, and thepices that they are quoting me are a bit scary!...£400+...
So can someone please help me and put things into perspective, is this right?what problems occur with a ecu problem, and where can i get the best service to correct this... :?


Thanks

Humair
300CE '90'

 

[talbir]

Check the OVP relay - this is a small silver box (approx 2" x 3" tall), with a red or black plastic lid. Inside the lid, there is a 10A fuse - replace since it is most likely fused. This is most likely if you have jump started the car recently.

The relay is situated behind the battery - remove the black plastic cover behind the battery and you will see the OVP relay.

Hope this solves the issue - may be another problem but highly likely from the symptoms that you describe that it's the OVP relay fuse that simple needs replacing.


talbir

 

[Richard Moakes]

Find yourself someone who doesn't guess, and applies diagnostic principles.

Talk to Andy at www.mercedesservicing.com he is from the old school of servicing, not a component swapper.

If it starts poorly and petrol consumption is high, then it is *probably* a mixture issue, which can be caused by many things. I would start by having a gas analyzer put up the exhaust and see what it says about the mixture.

Then, I would start by looking at the condition of the air filter, spark plugs and rotor arm/distributor cap, and perhaps the ignition wires. Note I don't say replace them, I would check the condition of these items.

If the mixture is rich, then an person experienced in KE Jetronic is required, this system is primarily mechanical and NOT electronic and therefore it is more likely that the cause will be physical rather than electronic. In fact it is possible to run the engine without the ECU having any power, I know this for sure, as when my OVP relay gave out, I managed to get home without the assistance of the KE Jetronic ECU :wink:

Good Luck,

Richard
1989 W124 300E

 

[Humair]

Thanks alot guys, help much appreciated!

Humair
300CE '90@