Mechanics

THROTTLE BODY PROBLEM

1994 Mercedes Benz 200e • 259,433 miles

I bought this car 4 years ago from a friend. The Local Garage (Car Maintenance shop) told me that I need to change the Throttle Body because the idle was not good and I bought one from a friend who was keeping it for replacement. When they installed it, it was doing great but when I start the car in the morning it start up but would not hold the idle so I took the car to the mechanic and he told me that it (the throttle body) has to much carbon deposit and he cleaned it and the car was doing fine except the RPM is always at 11K. So I took it again to the same guy and told him to minimize the idle and he open the throttle black cover and tune it. Since that day, In the morning the car cannot hold the idle and also if I park the car and went for something for about 1 and half hour and starts the car it cannot hold the idle. As a solution, I have to put my foot into the fuel pedal for about 2min to warm up the engine then it (the Throttle body) will hold the idle and warm up the car.

My question is, is there a solution for my problem? Was the mechanic correct to open the black cover of the throttle body to adjust the idle? Can it be tuned back? Please help?
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Lusieth
June 14, 2012.



What is the idling speed after warming up?


KHLow2008
Jun 14, 2012.
The idling speed after warming up i.E. After the temperature reach 80c is 800. However, my problem is not after the engine warms up it has no problem during that time. The only problem I have is in the morning and day time if I stopped the car for 30min or 1hr. During that time it does not hold the idle (the car starts perfectly and the rpm goes to 1K and then immediately drops down and the engine will shutdown, to avoid this I need to step on the gas pedal a little bit for 2min and so).

I hope you understand my problem and thank you very much for your fast response.


Tiny
Lusieth
Jun 16, 2012.
Our database does not have any information for your vehicle so I hope what I have for you is applicable.

I don't know what the mechanic adjusted but if it is for air fuel mixture adjustment, it is not as simple as tweaking around. You would need a 4 gas analyser to do that to be accurate.

I need to know the idling speed as it could be related to your problem and since you are having correct idling speed, the problem lies with the cold (fast) idle system which is actually computer contyrolled and you cannot make any adjustment to it. The component likely to cause this problem would be with the by-pass air valve. It could be clogged or not functioning correctly.

Have you checked for trouble codes?


KHLow2008
Jun 16, 2012.
I think he did air fuel mixture adjustment. I attached the picture that he opened and done the adjustment. By yhe way what is a 4 gas analyser? Thank you so much gor your cooperation.


Tiny
Lusieth
Jun 21, 2012.
4 gas analyser is a tool that is plugged into the end pipe of the exhaust to test the gas content and perform adjustment accordingly to get it correct.


KHLow2008
Jun 21, 2012.