Can you tie the sensor ground to engine ground?

[Rwilner]

Hey All,
My engine is aircooled (Porsche 914 flat 4) and does not have a coolant temp sensor, it only has a cylinder head temp sensor. The CHT is a 1-wire sensor -- the ground is the body of the sensor to the engine case (similar to a spark plug ground).

If I connect the single wire to pin 25 of the ampseal, I read an open circuit because the MS sensor ground at pin 20 is isolated from the engine ground. One option for me to fix this is to tie pin 20 to pin 21/22/23, either externally or using a small jumper inside the MS ampseal connector. I verified that this will work using a test lead externally. Is it ok to tie the sensor ground to the other ground connections?

Thanks for your help!
Rich

[Matt Cramer]

It will be a bit noisier but can be done.