Results 1 to 5 of 5

Thread: MFI Microswitch - Linkage Interference

  1. #1
    Member Bahman's Avatar
    Join Date
    Jan 2021
    Location
    Greensboro NC
    Posts
    97

    MFI Microswitch - Linkage Interference

    While adjusting the MFI throttle linkage system end-to-end on my ‘72E for full opening at the butterflies, I discovered that at 90% opening, the actuating lever on LH side (in the microswitch vicinity) comes in contact with the rear wire terminal of the microswitch, stops bout ¼” short of full stroke, and tends to bend the rear wire/terminal junction of the microswitch. The microswitch, bracket, and wiring harness of my car are all original and never been tampered with.

    Regardless, I removed the microswitch and rotated the L-shaped rear tegminal 180 degrees (it is attached with a tiny screw) and reinstalled it. This rotation moved the terminal inward by about 3/16”, enough for the linkage to clear the rear terminal/wire and move freely.

    Please note that the linkage for '72-'73 cars is different on the earlier MFI cars, and my observation may not apply to the earlier MFIs.
    1972 911E Targa, Mostly Original
    2002 Porsche 996 C4 Cabriolet
    2005 Turbo-converted MINI Cooper S

  2. #2
    Sounds like your pump to throttle bar linkage is misadjusted I believe it should be 112mm c-c then adjust linkage to throttle bodies. I ran into this issue before.

  3. #3
    Member Bahman's Avatar
    Join Date
    Jan 2021
    Location
    Greensboro NC
    Posts
    97
    Quote Originally Posted by kwikt View Post
    Sounds like your pump to throttle bar linkage is misadjusted I believe it should be 112mm c-c then adjust linkage to throttle bodies. I ran into this issue before.
    Thank you for your suggestion. That linkage is already at 113mm c-c (I believe specs are 112 +/- 0.2mm). I have already worked around this problem and was merely letting others know in case they experience a similar problem. As a whole, my MFI system is running very well; it was just not opening the butterflies 100%. It does now.
    Last edited by Bahman; 04-03-2023 at 05:53 AM.
    1972 911E Targa, Mostly Original
    2002 Porsche 996 C4 Cabriolet
    2005 Turbo-converted MINI Cooper S

  4. #4
    Senior Member 2.5MFI's Avatar
    Join Date
    Sep 2006
    Location
    Bend, Oregon
    Posts
    436
    [QUOTE=Bahman;1149981 That linkage is already at 113mm c-c (I believe specs are 112 +/- 2mm).[/QUOTE]

    The pump throttle rod should be 114mm.
    Mark Jung
    MFI Werks
    Early 911S Registry #972
    Carrera T w/LWB, MT, RWS, PCCB
    72 T 66 x 100 MFI Twin Plug Coupe
    R Gruppe #686

  5. #5
    Member Bahman's Avatar
    Join Date
    Jan 2021
    Location
    Greensboro NC
    Posts
    97
    Quote Originally Posted by 2.5MFI View Post
    The pump throttle rod should be 114mm.
    I have now adjusted that link to exactly 114mm c-c, but it does not solve the interference I reported in my original post (i.e., interference of the linkage with the rear microswitch terminal/wire at full throttle.)
    1972 911E Targa, Mostly Original
    2002 Porsche 996 C4 Cabriolet
    2005 Turbo-converted MINI Cooper S

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Message Board Disclaimer and Terms of Use
This is a public forum. Messages posted here can be viewed by the public. The Early 911S Registry is not responsible for messages posted in its online forums, and any message will express the views of the author and not the Early 911S Registry. Use of online forums shall constitute the agreement of the user not to post anything of religious or political content, false and defamatory, inaccurate, abusive, vulgar, hateful, harassing, obscene, profane, sexually oriented, threatening, invasive of a person's privacy, or otherwise to violate the law and the further agreement of the user to be solely responsible for and hold the Early 911S Registry harmless in the event of any claim based on their message. Any viewer who finds a message objectionable should contact us immediately by email. The Early 911S Registry has the ability to remove objectionable messages and we will make every effort to do so, within a reasonable time frame, if we determine that removal is necessary.