what is the sensor behind the carb and in front of the distributor on the top of the manifold. i took it out and it looks like some sort of temperature sensor. it isnt hooked up on my car so i want to find out what it is. 5.7 L quadrajunk.

 

There shouldn't be a sensor there. Just a vacuum fitting that is typically connected to the HVAC system under the dash. All the senors that screw into the intake are usually up on the front of the manifold, screwed into the water jacket near/on the thrermostat housing.

Got a picture?

 

ill get a couple in about a day.

 

gotta bring it back from the dead...

what is this

 

Dude that looks like a fan switch or coolant temp sender. Anyway that should be a vacc. port. That does not go there.


Brian Felts

 

you lost me after sender. dont have electric fans and the coolant sender is on the driver side head. the block is a stock 305 lg4. im pretty sure the intake is stock , so why wouldnt that go there?

 

It doesn't belong there.

Looks like a classic case of, "I don't know what goes here, but this fits so that must be it".

 

damn that NPT standard!

 

Yeah you are right the temp sensor goes down by the head but that sure looks like one thats badly out of place.



Brian

 

HA HA HA!!! Yep, that's one lost little CTS (Coolant Temp Sensor)!!! It goes up in the water jacket near the thermostat housing.

You have 2 temp sensors on that engine- one is in the driver's head and runs the gague on the dash. The other is in the CTS sensor near the thermostat housing and the car's ECM uses it to monitor engine temp.

Just when you think you've seen it all..........

BTW- Do NOT reuse that sensor even if you figure out where it goes. I can't imagine it's in tip-top shape any more. It might even be a sensor from a completely different car!

 

see the chains, the engine is getting overhauled. i think i might as well as replace the sensors while im at it.

 

That looks like an electric radiator fan coolant temperature switch to me. Goes in the passenger side head of cars with electric fan. The coolant temperature sensor (CTS) in the thermostat housing is a two-terminal device. The coolant temperature sender for the gage in the driver's side head has a different type of connector.

If you don't have an electric radiator fan, then this device certainly came from a different car. As previously stated, there should be a vacuum tee fitting in that location.

Contrary to urban legend, sensors rarely go bad unless distressed in one way or another. The only one I've replaced in over 4 years of driving this car is the same electric radiator fan coolant temperature switch. The only reason I replaced it is I wanted one that turned the fan on at a lower temp when I did the engine mods in the sig. When I first did the engine swap, I replaced a vacuum temp switch on the intake manifold that got broken by the lifting sling ("distressed", as I stated above).

 

That's funny! Somebody used a fan switch as a pipe plug, probably because they couldn't find a 3/8" pipe plug laying around right at the instant they needed it.

Ignore it. It may look amazingly like a sensor, but in reality it's only plugging a vacuum leak.