REVS PROBLEM

Andreas290

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Your Mercedes
E200, W124, 1994, petrol
I have an E200, petrol, automatic, W124, built in 1994. Recently I encountered a problem with the revs of the car. The revs are not stable. The car might start and switch off or start at low revs and when the engine is loaded with e.g. with the ac or power steering and the gear the car will switch off. When started again it might do the same or start at high revs of 1500. When at 1500 it will not adjust and is pretty dangerous to stop as it will behave like the petrol is pressed at the same time that the brakes are applied. When switched off and on sometimes it resets to normal revs but still does not behave normally. My mechanic suggested a throttle replacement. Is there anything else that might cause that? like a wiring problem or vacuum tubes? Can the throttle be repaired ? Thanks for spending time reading about my problem.
 

kid-jensen

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Ml320CDI 2007
Uneven idling and stalling can often be air leaks in the inlet manifold, either by dodgy gaskets or vacuum lines letting air in.

Start by blocking-off all the vacuum lines and see if things improve.

Don't drive it with the servo line disconnected though!
 
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Andreas290

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Thanks a lot PaulG......I will check it out
 

DREAMER NO2

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Your Mercedes
W124 2.6E M103 1989
As Paul said in his post above .Also remove the idle control valve and clean it out with white spirits .The engine temperature sensor might be faulty it causes lots of problems like you have . The other is the large rubber type gasket under the fuel distributor they split over time .. I would go along the lines of replacing distributor cap,, rotor arm ,,ht leads ,,and plugs ,,,thats if you have not done so .Check all the fuses,remove one at a time spray the ends only with wd40 lightly wipe the ends of the fuse and then refit them .. ,clean and grease all the earth leads to body. Then go from there on to other fixes if no change ..
 
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Andreas290

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E200, W124, 1994, petrol
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As Paul said in his post above .Also remove the idle control valve and clean it out with white spirits .The engine temperature sensor might be faulty it causes lots of problems like you have . The other is the large rubber type gasket under the fuel distributor they split over time .. I would go along the lines of replacing distributor cap,, rotor arm ,,ht leads ,,and plugs ,,,thats if you have not done so .Check all the fuses,remove one at a time spray the ends only with wd40 lightly wipe the ends of the fuse and then refit them .. ,clean and grease all the earth leads to body. Then go from there on to other fixes if no change ..


Thanks a million I will check all these out
 

DREAMER NO2

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W124 2.6E M103 1989
The idle control valve will have two or three hoses from the rear mind you put them back in the righ place after removal .You will be looking for splits in said hoses ,if there is replace them . Another check is start the car up in the dark than look in the engine for blue flashing from one item to another .
 
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Andreas290

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E200, W124, 1994, petrol
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The idle control valve will have two or three hoses from the rear mind you put them back in the righ place after removal .You will be looking for splits in said hoses ,if there is replace them . Another check is start the car up in the dark than look in the engine for blue flashing from one item to another .


Thanks I will give it a check too
 
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Andreas290

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E200, W124, 1994, petrol
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Finally the problem was solved but I waited for some time before posting just to make sure that all is ok and running.

The problem was at the connection plug of the throttle. One of the pins of the plug was broken (earthing wire) and we had to make some modification in order to bypass the plug and reconnect the wire. All is good and running now, even the AC (climate control) is operating much better now. Before, with the problem of the throttle, the AC was coming on and off at will, but now with that earthing wire reconnected it runs smoothly.

Thank you for your support
 

EmilysDad

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Your Mercedes
ML350
Finally the problem was solved but I waited for some time before posting just to make sure that all is ok and running.

The problem was at the connection plug of the throttle. One of the pins of the plug was broken (earthing wire) and we had to make some modification in order to bypass the plug and reconnect the wire. All is good and running now, even the AC (climate control) is operating much better now. Before, with the problem of the throttle, the AC was coming on and off at will, but now with that earthing wire reconnected it runs smoothly.

Thank you for your support
Glad you're sorted. Not an obvious fault.
 

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