w202 c200 engine cut out followed by misfire

[montur]

w202 c200 engine cut out followed by misfire

Please anyone have any idea's on getting this problem sorted. I have a 1998 facelift model and it was driving perfectly untill today. I drove home and as i was about to park up the engine cut out. I tried to fire it up again but it misfires for 2 seconds and then cuts out. now it turns but doesnt fire up.

I have changed the plugs, cleaned the MAF and throttle body and idle speed control valve and still not firing as normal. I had a friend of a friend come with his diagnostic equipment. He rigged it up to the 38 pin connector and couldn't get a fault code off it. He suggested the fuel pump relay as i have spark. I have ordered one from the stealer and it should be here on Tuesday will post details of outcome then inc. cost.

 

[montur]

Update

I got the relay. They didn't need to order it so i could have got in on friday (liars) fitted it. Still the same problem. I now think immobiliser related fault so I am getting the car towed to Pentagon mercedes in Portsmouth on Thursday to get it checked out. Ouch!

 

[nickmann]

I would have gone for the fuel pump relay too. The missfire pointed to fuel.

 

[jgevers]

Common causes of missfires on w202:

Wiring from ecu
ecu failure
coil failure

first thing to do is check for switching signal from ecu at both coils with a scope.

If switching signal is there, it will be faulty coil.

Cheers

 

[montur]

Hooray, Problem solved

RAC came and had a look at car before towing it. He tested the fuel pump in situ to see if power and signal was being received. That was OK. So all he did was get some fuel and filled it up about 4 litres and rocked the car. The car started on 2nd go. :bannana:

Now i am no fool the tank has over a quarter unleaded in it. Our conclusion is that there was an air trap at the pick up in the fuel tank. Adding the fuel and rocking the car released the bubble and allowed fuel to pass through.

The moral of the story is you should always try the cheapest options first and don't dismiss the most daft scenario, as in the end all it probably is, is a simple fix.

 

[montur]

Broke down again

Broke down again

Yesterday i was happily coasting on the motorway and the car lost power (not stalled) so i pulled over onto hard shoulder when i came to a stop the engine cut out. Called RAC and the guy said it sounds like there is no fuel, but i know there is over a 1/4 tank in there. He went and got some fuel and car started straight away. So this time i am not thinking air lock. I got home and had a look under the car. The tank seems saddle shaped so there are 2 sides to the tank so i think there is a blockage somewhere between the 2 sides so the fuel isn't allowed to pass between each side. I am going to put some Slick 50 fuel treatment in next time i fill up to see if that clears it. If not i also have some Prolong fuel treatment.

Does anyone else know of aggressive fuel treatments so that i can clear the blockage without removing the tank???????