1992 300E cutting out

[Martin-Jundiaí]

Hello there,
A strange thing has started to happen with my 1992 300E, a few minutes after starting her up she cuts out in motion or stopped at lights, this quirky behaviour is indifferent. However, it doesn't always happen. The air cleaner filter does need changing although I don't see a strong connection there though.

At first, I thought it was the radio controlled immobiliser I had fitted but as I had that professionally checked it was excluded. The batteries for the controller are also new.

The car does have the usual warm starting problem, although she starts from cold without any problems. Once she has started up the motor runs smoothly and the car pulls away well. The mileage is +/- 125,000KMs, around 80,000 miles.

I'd gratefully appreciate any suggestions.

Martin in Brazil

 

[Xtractorfan]

The CPS crank shaft position sensor immediately comes to mind..worth a check

 

[TELF]

I don't know how similar this might be but my 1999 SLK used to cut out after exactly 40 mins (bit of an issue at 80 in fast lane!). I could even stop the car after 35 mins and restart and it would be fine all day. Turned out to be voltage regulator/relay base. wasn't dear to replace and been fine ever since. Another symptom was alarm going off sponmtaneously when car was stood.

 

[television]

The fuel pump relay could be dry soldered on the PCB where the relay is soldered on

 

[Martin-Jundiaí]

The fuel pump relay could be dry soldered on the PCB where the relay is soldered on

I'm not quite sure what you mean. Could you explain a bit more. Thanks, Martin

 

[television]

Its the hardest of all to find out why a engine just stops.


If always only when hot then as Xtractorfan said the CPS is a known issue.

The fuel pump relays can get bad connections on the soldered joints, this is also a known problem, and easy to remove the cover and re solder the relay its self where it is soldered onto the board

 

[Martin-Jundiaí]

Malcolm, I'll look into the CPS and the fuel pump sensors. But my guess is they are not for the home mechanic to do! There are NO MB garages, authorised or indie, where I live and mechnics have the swap out policy in a lot of garages.

I'm used to working on older MBs so the W124 is a bit modern for me! However, one can but learn too. I do have the Haynes manual, which is not as good as they used to be, so it should help guide me through.

 

[Martin-Jundiaí]

Since I posted this thread the car has not cut out again! It could have been some dirt on the sensor or the suchlike?

I've heard that the M103 motor has as many small quirks as it does ways to fix them, so maybe I'll just have to live with it! TBH, I don't think the W124 is all that it's cracked up to be and would much rather have another older model! Pity, cars not that easy to sell over here at the moment.

My W116 doesn't have these personality crises, she's just has a good old-fashioned carb, points and simple engineering!