MFI Micro Switch question

[Gearbox]

Quick question about the micro switch mounted on the throttle body that controls the RPM Transducer. When the throttle is closed, is the micro switch "on" (closed connection) or should it be off? Thanks.

[Zeke]

I believe it's closed as opposed to open.

[dogslovetrucks]

Not to be dumb but what does the micro switch really do and can you live without it?

[jeff m]

The speed switch (transducer) detects the RPM and sends a signal to the micro switch. If your foot is off the gas (butterflys closed) this is passed on to the fuel shut off solonoid which ops to prevent unnessassary fuel on overun.

Yes, you can live w/o it.

[Gearbox]

Thanks for the help, does anyone know where I can source a new one? Thanks again.

[Early_S_Man]

These are standard, full-size, microswitches that have plunger overtravel, and date back to the 1950s. Here is a datasheet:

http://www.alliedelec.com/Images/Products/Datasheets/BM/C_K_ITT_CANNON/CandKITTCannon_Industrial-Control_6764196.pdf

Pelican can get the 901.613.106.00 microswitch, but $124 seems a bit steep. A suitable replacement is available from Allied Electronics:

http://www.alliedelec.com/Search/ProductDetail.asp?SKU=676-4199&SEARCH=&MPN=ASKHC2J04AC&DESC=ASKHC2J04AC&R=676%2D4199&sid=46859D0011B0617F

There is also an ITT/Canon HB-series heavy duty switch rated 20 Amps available from Digikey, section 'I', p. 1811, Digikey pn CKN1419-ND, for $14.11 @ qty 1, ITT #HBS2KCB4SJ055C. Also, same exact switch available from Allied for $14.86 ... here are the Allied pages and spec sheet:

http://www.alliedelec.com/Search/ProductDetail.asp?SKU=676-4184&SEARCH=&MPN=HBS2KCB4SJ055C&DESC=HBS2KCB4SJ055C&R=676%2D4184&sid=46859D001692617F

http://www.alliedelec.com/catalog/pf.asp?FN=991.pdf

http://www.alliedelec.com/Images/Products/Datasheets/BM/C_K_ITT_CANNON/CandK-ITT-Cannon_Industrial-Control_6764184.pdf

[Gearbox]

God do I love this forum, THANKS Allan

[justacoupe]

I found a replacement microswitch and have a wiring question ('73E MFI 2.4). The new switch has three wire connectors: common, norm open and norm closed.



The original only had two connections. Looking at other posts, I believe I should wire up to the common and the "norm closed" but want to confirm that. Also, the wiring diagram shows two different colored wires connected to the microswitch. However, our car has original harness (one owner) and both spaded connectors are red/gray striped wires. I marked the wires before removing them, so I know which one was mounted to the terminal below the actual "plunger" on the original switch. But I guess it doesn't matter?



Thanks in advance... and Happy New Year.

[Flieger]

I think you want it norm open. You want it to close when the switch is depressed.

[cooklook]

I ordered some switches here, the price is relatively cheap. https://www.allicdata.com/list.html?category_id=2291