Mercedes E230 Ecu trouble

Jankoria

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Hello All . I need a second oipnion on my Mercedes E230, 1996 Auto
Went for Mot, the Mechanic said failing Emmission test he Firstly thought
the Mass air flow meter faulty, changed, still failing, so second guess Lambda
sensor replaced it passed. Before it went for MOT the engine would idle very
rough, hunting is the term i think. Still the same problem exist. I have been adviced it is the ECU failing. Whoooh when he told me how much severe pain somewhere. Any experts in the forum can hopefully guide me in the correct direction. In the older type of cars this would be a standard symptom of
vaccum tube dislodged or leaky on the distributor diaphragm.
Any Help on the matter most appreciated.:confused:
jan
 

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Hello and welcome to the forum,,it is not an easy question.

First hunting, that is revs going up and down are more to do with air leaks around the inlet somewhere,,I cannot see this as being ECU related, a petrol engine needs air in order to speed up, OK to much fuel and the engine speed will fall below the standard RPM as it would be choking.

I cant recall an ECU ever causing the fault.

Most of these cars will pass the emission test by giving the car an Italian tune up
 
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Jankoria

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Hello Malcom
Thanks for the reply, what is an Italian tune up ( excuse the Ignorance )
I'll have a look around the Inlet manifold and the Throttle body. I can see
the Butterfly linkage jerking, makes me think it may be the Throttle potentiometer
There is a sensor on the top housing of the throttle assembly, any Idea what does it's
function.
Thanks Regds Jan
 

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An Italian tune up is where you lock the car into 2nd gear and take it for a hard drive,,that is the way many have to pass the test.

Re the hunting,,one needs to take the correct idle for the car, if it is say 750 rpm, then if the car hunts above this speed then it is air leaking in,if it is below then the fueling is too rich.

Wait till some of the other experts come on,, you have temp sensors and other things that could cause the fault
 

Alex Crow

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for the hunting idle i suggest cleaning the throttle butterfly, carburettor cleaner works very well.
 

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Try cleaning throtle venturi and then boot strap it.
 

Cole@MBS

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Wait for it Ian!!

Boot strapping????

Its a thing of the past now mate!!

Last time i did that was on a SLK after fitting a new battery and lost the throttle!!
 

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I've been caught out before, then you get one that wont run right and needed doing :)
 
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What is boot strapping
 

Cole@MBS

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Its a program that reset the throttle body/throttle stop, common with the older stuff Malc,

Common with the 170!!!!!
 

Alex Crow

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also resets the fuelling self adaptation, possibly the sensor rotor adaptation too but i can't remember everything!!!
 

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