Head Temp Sensor question

polizei · 03-18-2008, 08:43 AM

I have an '87 Carrera on which I'm performing a top-end rebuild. What is the sensor/device which shares a grommet with the Head Temp Sensor? Whatever it is, the rubber insulation on its wire is torn. Is this something that I can just "re-insulate" or does it need to be replaced?

ChrisBennet · ChrisBennet's Garage

The head temp sensor, the speed sensor and the reference sensor all share a grommet. If the speed sensor and reference sensors are original (cracked insulation) replace them. I've seen several fail once they are that old. Replace the head temp sensor if it is the single wire kind (1 pin in the connector).
-Chris

88911coupe · 03-19-2008, 06:17 AM

Chris, what are your thoughts on using the BMW equivalent for the speed/reference sensors? Also, aren't they identical to each other?
I know several on the board have used these with no apparent problems and I plan to do the same thing on the rebuild I'm doing on my '88.

ChrisBennet · ChrisBennet's Garage

Quote:

Originally Posted by 88911coupe

Chris, what are your thoughts on using the BMW equivalent for the speed/reference sensors? Also, aren't they identical to each other?
I know several on the board have used these with no apparent problems and I plan to do the same thing on the rebuild I'm doing on my '88.

I've never tried it but I don't doubt it would work.
-Chris

polizei · 03-19-2008, 11:13 AM

Where can you purchase these sensors? I can't seem to find them on Pelican.

88911coupe · 03-19-2008, 02:48 PM

I'm sure Pelican sells them, we just need to confirm the part #. It's simply a BMW speed/ref sensor but happens to work perfectly for the motronic 3.2.

safe · safe's Garage

Quote:

Originally Posted by ChrisBennet

Replace the head temp sensor if it is the single wire kind (1 pin in the connector).
-Chris

What's the problem with the single wire sensor?

polizei · 03-26-2008, 04:40 AM

Does anyone know the part number for the speed sensor?

ChrisBennet · ChrisBennet's Garage

Quote:

Originally Posted by safe

What's the problem with the single wire sensor?

It grounds through the head and for some reason this ground path fails (I guess) making it look like infinite resistance/open circuit. The "new" (probably been around 10-15years) sensor has a 2nd wire for the ground.
-Chris