shams13

hi all,

have some problems with 230E M102 and if somebody has a solution is welcomed.

1) cold start problem. have to do cranking for almost 5 seconds. Checked the water temp sensor and seems fine.(it seems to be little over reading; 4.5K at 20C). Is this a problem of OVP relay. How to check it??

2) once started, tend to be very sluggish on acceleration (actually doen't accelerate on heavy throttle). once reached optimal temp it runs fine.

3) idle is fluctuating between 600-750.

4) overall i don't feel much power in acceleration but the top speed is good. i can make 195Km/h.

please advice.

Brian Felts

Try something simple first......when was the last time the fuel filter was replaced. However that would not explain it running fine at running temp. I would then guess to go back to a sensor reading wrong, a MAS if your car has one (not too down on the 102) could be a reason or is your cats clogging and not operating until they get good and hot at running temp?


Some ideas.
Brian Felts

dan0jun

The O2 sensor information comes from my dad (a certified MB tech for over 30 years). The O2 sensors tend to go bad on MB's after 120,000 miles or so. Check the O2 sensors (will need either an ohm meter or a MB tech can do this) and I'm not sure if the MB uses a typical Mass Air Flow Sensor but if it does, find the throttle body - should be located at the end of the airbox - and within the throttle body you should see a pillar that houses two tiny wires. DO NOT TOUCH THE WIRES. Take a can of brake cleaner or carb cleaner and spray down the wires, making sure that any dust or grime that comes off the sensors is also cleaned off the entire throttle body. It is recommended that you remove the throttle body assembly from the engine during this process so you don't send any contaminants into your intake manifold. These are two small steps you should take before going to take your car in to get diagnosed.

Brian Felts

That is one more idea on the O2 that changes reaction when the car reaches a certain temp.


Brian

dan0jun

If your car does not respond to any of these suggestions, and if you are in the Southern California area, I would recommend taking your car to my dad's shop. He has worked for MB North America as both a technician and manager for over 30 years. He now owns his own shop and has dealt with this problem before (mainly on our own 1988 300E). I do not know the full repairs done on our W124 to fix these problems or else I could list some other points to check. Let me know if you would like his shop phone number, he is located in Riverside off the 91 freeway.

A slight disclaimer, if your problems result from numerous sensor or part failures, the repair estimate may be a little steep.

dan0jun

Ok, so last night I learned that W124's did not use a MAS. Instead it is called a CIS [Constant Injection System]. It reads the air flow mechanically by forcing intake air to push against a circular flap. The air pushes the flap open as it flows by, where the flap is attached through a series of links to the fuel pressure sensor. The farther the flap opens, the farther the flap leverages the fuel pressure regulator open, thus allowing more fuel. Just clarifying my mistake, don't want you searching for a part not there .