The short version: 20 years ago I converted my 1987 RX-7 to a V8. At the time I installed a T5 transmission which drove the speedometer cable. This past summer I installed a T56 which does not have a cable drive, so I installed a Dakota Digital ECD-100 which drives the speedometer cable. All worked well until recently with the cold weather. The system is binding. Cables are fine. Speedometer is fine.

I discovered a speed sensor approximately 10" from the back of the speedometer which might be the point of binding when cold. It is inline with the speedometer cable and driven by the speedo cable. It is about 2 or 2.5" in diameter, black plastic, and on it is written "59D-02552-2" "4 pulses per rev".

I do not have a 1987 manual. I do have a 1988 manual. Maybe this is buried in the manual somewhere, but I have not seen it.

The car does not have ABS, and never has.

What is this speed sensor for? I am wondering if I can remove it since I do not have a Mazda engine in the car.

TIA

 

I don’t think that’s stock. Can you take a picture? I am guessing its for aftermarket cruise control.

 

It's not stock as there was nothing between the speedometer and the cable. But I also wouldn't mind seeing a picture of what you have.

 

the factory manuals are here, Foxed.ca - Mazda RX-7 Manuals