vaccum valve?

[deportes]

0015407097
Mercedes (OE)
Vacuum Valve; 3-Way Switchover Valve with 3 Vacuum and 2 Electrical Connections
Multiple use relay for EGR, fast idle, transmission control, shift-point, starting booster, manifold pressure compensator, air pump, etc.

1992 500SL

How do you test this valves? there are 4 valves under the left hand cover next to the engine.

Trying to find the vac problem that causes the erratic rough idle,for example today coming back from lunch, at the stop light with air cond OFF the car was idling fine, I wasn't driving very constant without pushing it prior to that stop, 2 minutes later, after arriving home when I set it on Park the rough idle came back.

[duxthe1]

On this car I would start diagnosis by first ckecking the basics, fuel and spark before suspecting probelms with the valves mentioned. They are for control of ancillary devices and do not affect the idling of the engine without a seriously oddball failure. The most likely culprit of an intermittent rough running at idle is the fuel distributor, which just happens to be a very expensive part. Ignition problems are common as well. The way to spend the least money on repairing it is to have a competent technician diagnose it.

[deportes]

I agrre, after searching for idle problems on M119's, took apart the Distirbutor cap's and cleaned them as well as the rotors until I order new ones.
The price for theses beauties is incredible, I used to buy caps and rotoe for old VW that cost a few bucks, these suckers will set you back a couple hundred bucks.

Will post my findings as soon as I test drive it.

[deportes]

Took the beast for a test drive and to my surprise it idles a lot better, just a little miss. Now I need to replace the caps and rotors with some new ones.
cough cough. Maybe wires as well cough again