QVHK

The M103 engine on my 1990 300CE has been performing very well. Recently, it stalled occasionally, once or twice every few days, at low speed (when I was slowing down and depressing the clutch prior to stopping). As I was planning to replace certain parts anyway, so I fitted a new EHA, spark plug wire set, new air filter, fuel pumps (x2), fuel filter and fuel pump relay, and tried to see if the problem would go away. Car then ran fine for five days but it stalled again, twice today, same situation as before. So it seems the new parts did not help with the stalling. OVP was replaced last year. Wonder what might be the problem?

Saijin_Naib

Cap/Rotor/ and spark plug wire set helped me with that issue.

You should have the m104 btw Just like me. Rejoice!

Durbo20vT

ever solve this issue?

QVHK

The problem eventually disappeared for no obvious reasons. In fact, before problem disappeared, the stalling was coupled with a sudden surge in idling to 1500 rpm. I did a thorough research on these symptoms, and stalling and sudden surge in rpm have several possible causes: air leak, toasted idle control valve, worn rubber seal of fuel injector, worn rubber seal in brake booster, defective OVP, EHA, Fuel Relay, etc, etc., the list goes on and on. To cure such problem would have to go through trial-and-error starting with the least expensive option. My mechanic cleaned the idle control valve, problem subsided for a few days and then returned. I was ready to order all the possible parts needed but while waiting to confirm order, the stalling problem as well as sudden surge in rpm have both disappeared.

My guess is that the equilibrium was upset after my changing of the EHA, and the engine re-adjusted by itself and has now finally re-established best-fit position. :0