Sensor grounds

[GTRS Fiero]

Some sensors have teflon tape applied; other sensors have some hard red stuff; still other sensors have neither.  What is that red stuff, and how do the sensors ground, if they have tape or the red stuff?

[GTRS Fiero]

Anyone?

[Fierofool]

The red coating is a conductive sealer.  Teflon tape isn't conductive and shouldn't be used on sensors that ground to the engine through their base.  If the sensor is bare, you should be able to use teflon tape. 

Single wire sensors usually ground through the engine.  Multi wire sensors may or may not.  The temp gauge sending unit grounds through the engine even though it's two wire.  That's because each wire performs a separate function.  Both the wires are actually grounds for that function.  The CTS sensor doesn't ground to the engine.  It has power in and power out to the ECM. 

[GTRS Fiero]

The fan switch comes with teflon tape.

The IAT & CTS have the red stuff.

The cold start switch and temp sensor have nothing on the threads.

[PK]

And again I am learning stuff.  Think it's the CTS I removed for access doing water pump. It had Teflon tape on but above suggests it shouldn't?

[GTRS Fiero]

The CTS can have teflon tape.

[Fierofool]

I use anti=seize compound on sensors that don't have the brown, sometimes almost black, thread sealer on them. 

It's possible to get a ground through teflon tape, but it wouldn't be the best ground possible.  I've never fooled with the cold start injector so I don't know how it's set up.  If it's a 2 wire injector, it wouldn't need a ground to the engine. 

[Raydar]

I frequently use plumber's paste or pipe joint compound for sensors. It seems to provide an adequate ground. At least I've never had to redo one.

The CS injector uses two wires. As does the CS thermal switch.

[GTRS Fiero]

If you use minimal teflon tape, it does seem to get a ground.