Hi. On my daily driver, an 85 Caprice V8, I am running a 180 thermostat instead of the stock 195.

I am wondering if the lower engine temp will affect the operation of the "air cleaner temperature sensor" which is located inside the air cleaner.

The hot air intake flap, which is controlled by the air temp sensor, is almost always closed, taking in heated air from exhaust man box, even after the engine is hot.

I am wondering if putting the 195 tstat back in will make the sensor get hotter and open the flap sooner.

Basic question : does the sensor pick up heat from the engine, or just from the air
coming in ?

Answering my own question, it seems that the answer is yes, engine temp matters, since normally the flap is open, sucking cold air, even on a cold day, after the engine is hot.

Any input appreciated.

 

Dude, the sensor is dead! My Trans Am has a 180* thermostat and have had no problems with warm-up. Come on $20 isn't that big a hit.
Or grab a new air cleaner from a local junkyard. 195* is just for emissions, since a warmer car puts out less junk into the air.
------------------
--Steve S--
1984 Trans Am 305 LG4, 5 speed
RPO codes point to Recaro version
Daily Driver, Flowmaster 80 Series

[This message has been edited by 84TransAm (edited February 02, 2001).]

 

GTA,

Is the vacuum line connected to the EFE valve actuator? The sensor (TVS) is supposed to act on incoming air temperature, and defaults to the closed (hot air) position. Some heat may be gained from the engine, but the air temperature is what should determine the valve position.

The manifold vacuum source needs to connect to one side of the TVS in the air cleaner, and the other line connects to the EFE actuator out on the end of the snorkel. On really cold days, the EFE valve might not open. If you check the vacuum at the actuator, it should be there after the engine and air temperature are higher. There should be a slight vacuum at the EFE valve. If not, the TVS may be failing or the vacuum lines might have been reversed. If the vacuum is present but the actuator doesn't open the valve for cold air, the actuator might be damaged or stuck.

------------------
Later,
Vader
------------------
"Make Me Bad..."
Adobe Acrobat Reader 4.0

 

Vader,

Sounds like you are saying the vacuum, allowed through the TVS sensor when it is heated, is what opens up the flap for cold air. But what I am observing is that vacuum CLOSES the flap, and sucks in hot air.

On a cold day, before starting the car, the flap is wide open for cold air. Obviously there is no vacuum when the car is off. When I start the car, and get some vacuum to the sensor, the flap immediatley shuts, sucking in only hot air.

My guess is that the TVS closes OFF the vac to the actuator when heated, allowing the flap to open for cold air.

I suppose I may have reversed the vac tubes, bypassing the switch, in which case there is always vac present at the actuator, making the door always shut, no more what the bypassed switch is doing. But I don't think I reversed them. I'll check.

But in the meantime, am I right thinking that vacuum to the actuator CLOSES the flap, and the pinching off of vacuum to the actuator OPENS the flap for cold air ??

 

Vader,

Sounds like you are saying the vacuum, allowed through the TVS sensor when it is heated, is what opens up the flap for cold air. But what I am observing is that vacuum CLOSES the flap, and sucks in hot air.

On a cold day, before starting the car, the flap is wide open for cold air. Obviously there is no vacuum when the car is off. When I start the car, and get some vacuum to the sensor, the flap immediatley shuts, sucking in only hot air.

My guess is that the TVS closes OFF the vac to the actuator when heated, allowing the flap to open for cold air.

I suppose I may have reversed the vac tubes, bypassing the switch, in which case there is always vac present at the actuator, making the door always shut, no more what the bypassed switch is doing. But I don't think I reversed them. I'll check.

But in the meantime, am I right thinking that vacuum to the actuator CLOSES the flap, and the pinching off of vacuum to the actuator OPENS the flap for cold air ??

 

Fixed it. Sprayed a lot of carb cleaner on the sensor, and cleaned out the little pin that is supposed to move up and down and bleed the vacuum. It was gunked up with some sort of slime, maybe gas fumes from the carb had congealed on it. Works fine now