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Old 12-16-2015, 09:52 AM
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Stretch Stretch is offline a shield of steel
Join Date: Sep 2009
Location: Somewhere in the Netherlands
Posts: 14,435
Originally Posted by 124126140 View Post
I want to make sure spark plugs are non resistor.
Yes the micro switch at throttle linkage.
Terminal #2 at EZL to ground to test if ECU is reading TPS. Terminal#2 is on
the four pole connector on ignition control module
near the X11.
Yes TPS is throttle position switch on front of throttle body.
Continuity at terminal #2 should be present only when return
spring is attached. Throttle plate should move slightly when spring is detached.
This was my problem, on the 92, and if you have replaced TPS I would check it's
Vacuum reading will let us know if there is a large leak.
I have a thread on Benz world 124 sedan forum (m103 high idle unless ICV disconnected)
It's on page #2 H.D. wrote in with helpful testing procedures.
Duxthe1 is correct ECU is missing a reading from a sensor.
Hope this helps
Note that there are / or can be two micro switches.

One is visible next to the accelerator wire that goes into the cabin and onto the accelerator pedal. (Remove air filter and you see it)

This one connects to the fuel pump relay and the CIS ECU

The other micro switch that is connected to pin #2 on the electronic ignition unit (left hand plug = sensors) is on the throttle valve under the air balance gubbins...

...this also goes to the CIS ECU but also goes to the ignition control unit (whereas the other just goes to the CIS ECU)

...I have a question about these two switches

Are they meant to operate at exactly the same time?

I have adjusted my throttle linkage as described in the FSM but the lower throttle valve switch operates before the top switch...
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior

Don't leave that there - I'll take it to bits!
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