Bosch MFI excessively high idle
Folks,
My first entry and am in need of help.
I have a '69 911E with mechanical fuel injection.
It starts readily and runs great at speed, but after initial warm-up, the idle speed goes to 2000 and wont come down. I must admit I have fiddled with everything and had a Porsche mechanic (not familiar with MFI) look at it and we are stumped.
What I think I know is that the RPM sensor that powers the fuel shut-off solenoid by way of the micro switch, doesn't appear to be doing its job. I can hot wire the solenoid at the microswitch and the engine shuts down immediately. Is this enough to be my headache? Does the engine actually need the shut-off solenoid to get out of the mid-range and down to the idle control. The thermo - switch seems to be OK, at least it is clean and moved and has plenty of heat coming out the exit side.
The RPM sensor was working at one point because I got into a loop once with a high idle speed. The rpm sensor just played ping-pong between its two settings. I blew the fuse that powers the rpm sensor and after that nothing (clue).
I think I have two problems: (1) the rpm sensor and (2) tough time adjusting idle speed.
All help appreciated
McClellr
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