Success – 2-wire cylinder head temp sensor

[PSJoyce]

A small job, but my first on this car. With a lot of guidance from Clark Griswald’s thread # 6578, I was able to successfully change the original 1-wire CHT for the updated 2-wire. A 2 ˝ hour job of which 1 ˝ hours were spent pulling out the upper grommet. No real trick other than prying with a screwdriver; in the end, the grommet just gave in.

I removed the heater duct in the engine compartment to gain better access to the plug.

Part number 930-606-915-00-M14 was a perfect fit in my 1985.

I did cut a slot in a 14mm deep socket to help tighten the new one in.

Fortunately, the new grommets went in easily by hand. I lubed the 3-wire with 303 Protectant, and it slid in relatively easily.

The upgrade did fix the hesitation and stutter I had at 2100 rpm when the car was cold, and it seems smoother throughout the RPM range.

All in all, a worthwhile project. Thanks for all the information here – it gave me both the knowledge and the confidence to take this project on.

Paul

[disfin]

Great job. These pesky little CHTs seem to be a recurring topic on this board. Whats the difference between the one and two wire? Is it like an O2 sensor with heat being the second (@third) wires? Ive never thought cut a socket before, very cool.

[PSJoyce]

The second wire is a ground -- the original 1-wire grounded through the socket itself, and not very reliably.

Paul