engine dying 300TE
 

Can anyone help with the weirdest problem. My recently purchased 300TE is a stunner, but.... it has a problem where the engine simply dies. There are no prevailing conditions, and it does it under load, on the over-run, uphill, downhill, slow, fast, hot, cold, if you get the picture? It simply dies, and then fires up again and runs normal. It sometimes will stall completely, if you are going slowly, and that's scarey, (no P/S, brakes etc.) then you turn the key and it acts like there is no problem.
My local garage found water in my tank, and drained and disposed of £60 of fuel (That HURTS) but it does not seem to have made any difference. They have changed the fuel filter but it is no different. Can anyone throw any light...

I had the same problem with my TE with the exception of the water in the tank. My idle speed control valve was sticking. It's located under the air cleaner with a couple of vacuum hoses attached. The pivot point on the back of it had rust on it therefore was not springing closed or open (don't know which) and the car would die but only when approaching a stop. This would not affect the car off of idle. It may be something to check if it does stall when approaching a stop.

What year is your car and what engine do you have?

I was going to suggest replacing your OVP, but on the older KE fuel injection systems, the engines will run fine with a failing OVP or even w/o the OVP.

1993 and newer 300TE's have the newer electronic HFM system, and could exhibit your problem with a bad OVP.

Bad fuel pump relay is a common fault that would cause these symptoms.

OVP relay problems will bring up the ABS light.

Dirty idle speed control valve would not affect high speed or on-load uphill operation.

Sorry, the car is 1988-9 2.9L does this help?

103 motor?


I'd be looking at the seconday ignition and the crank sensor.



Joe

Not likely OVP, very likely Fuel Pump relay - as Mick J says - it's a common problem.

If you're inclined, do a little searching on this forum and you'll find out where the fuel pump relay is and what it looks like, and you can open it up yourself to check for broken joints, which are usually the problem. I did around a year ago, resoldered them (easy job), and my random stopping problems disappeared.

Or buy a new one, they're not tooo expensive.

I'd put money on it fixing your problem.

Had my local people fit a new fuel pump relay, but the car still has the same symptoms and problem. Any other suggestions please?

Joe is a Mercedes Benz Service and Repair facility shop owner, so his advice is probably worth looking into. The rest of us are just knuckleheads...:D

check the...
 

...Hall effect sensor. It sets the idle speed based upon some math formula (don't ask me to explain it any further). When it is defective, the sensor can cause symptoms similar to the ones that you have described.

It is a tiny part that attaches to the back of the speedo in your car. Has anyone pulled the instruments out recently? Sometimes the sensor becomes disconnected when the instrument cluster is pulled out.

Good luck, those are marvelous wagons!