Quote:
Originally Posted by spkunkle
Hello,
I have a 1982 380sl that I am having trouble starting, if I hold down the throttle plate just a little it starts and runs fine. I removed and cleaned the idle control valve, checked that it is getting power, it hums and clicks when the key is turned, so I am guessing it is working. does adjusting the tower screw open that throttle plate?
the previous owner said the idle was to high so he had a mechanic adjust it, when I got it it was already warmed up and running and worked fine for the 20 minute drive back.
any help would be appreciated,
thanks, Sean
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The
"throttle plate" is not the throttle plate!! It is the air flow sensor plate, and moves not via the throttle linkage, but in response to air flow into the engine. When you depressed it you also moved the fuel metering plunger in the fuel distributor (FD) in the rich direction. In the event that the PO's "mechanic" turned the tower screw in the lean direction, it may have had the effect of reducing the idle speed (due to leanness), but it also made the basic mixture so lean as to inhibit cold starting.
Have you explored how the tower screw works? The upper section is spring loaded upwards, and must be depressed and slightly turned to engage with the lower screw, which is the actual adjuster. CW is richer, and changes should be limited to 1/8 turn increments with a total of four.
After that, if starting difficulties remain, a reevaluation of more components is in order.