Mercedes-Benz 1986 420 SEL

[KRIS]

After driving from work my car stops every time I took my foot off from the accelrator. I was told it could be the overload relay so I replaced it. I still have the same issue. The car starts with no problem but would not stay on idle. I hear the fuel pump as well so I don't think the fuel relay could be the problem. I would appreciate if some one can give some clues.
thank you.

 

[television]

I will do what I can to help.

There are three parts to your injection system. the throtle posistion switch mounted off the throtle cable end tells the main computer that the engine is at idle and signals the the idle control relay-computer to work. the idle control relay signals the idle control valve the correct RPM for idle.

The main computer only controls things off idle, so you can forget that. normally the fail safe is to have a high idle, you do have vacuam lines and electrical lines on the idle control solinoid mounted on the intake manifold by the thermostat. Time is a little short at the moment for looking up exact things, you could have contacts in the bottom of the distributor (double) and these could be at fault.
I think that your idle ECU is also your fuel pump relay, its in two halves and a part of it could be faulty.
Something to think about anyway.

Malcolm

 

[KRIS]

Thank you Malcolm. So do you think I should try the fuel realy next? or could it be the idle control relay/?

 

[television]

Thank you Malcolm. So do you think I should try the fuel realy next? or could it be the idle control relay/?

I think that the idle relay and the fuel pump relay are all on one module.


Malcolm

 

[KRIS]

Ok Thanks again Malcolm. I will try that out.

 

[television]

Ok Thanks again Malcolm. I will try that out.

These boxes can be taken apart and re soldered up as dry joints give more problem than components going down, but if you are not used to soldering electronics, have a TV man or the like do it for you , should not cost more than £10.
Malcolm