Some follow-up:

I tested the 4 pronged coolant temp sensor on the front of the head and it seems to be in spec. Around 0 degrees C this morning and ohms measured 5000 one way and 5500 the other, warmed up to 90 degrees C and measures 225 - 250 ohms.

But, following the Static tests according to the landiss.com page, I am getting some confusing results. If I put the black lead from my Sears 82139 into pin 2 on the X11 and the red lead in to pin 3, I get 70% - so far so good. But when I check the voltage, it reads 8.28 volts. Using the Landiss formula - 8.28/12 = .69, then 1 - .69 x 100 = 30%. HUH? (I did the same test on my '86 560 SL and it works according to the landiss specs). Going to step 2, when I deflect the air flow sensor plate, the 70% does NOT change at all. Again, on my '86 560SL, the duty cycle drops to 10% - as described in the landiss document. Back to the 300CE - the full load contact test is weird as well - if I read the 70% duty cycle (red in 3, black in 2) then the duty cycle jumps from 70% to 80% when I open the throttle completely - if I switch it around and get 30% (putting red in 2 and black in 3), the duty cycle jumps from 30% to 20%.

With me so far? Man, if anyone can sort this out - I would greatly appreciate the help!

Anyway, I think I have a bad throttle valve switch on the 300CE - but I can't find the part ANYWHERE. There is a part number on the switch that is attached to the throttle body - 201 540 42 45 - but this brings up the entire throttle body assembly - for $350!

Can you not just replace the switch? Any help?

ryan

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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE