'89 RS - In trying to diagnose a fueling issue, I pulled the air cleaner off - and the cable/pipe shown (that attaches to the arm) came off somewhere! I have no idea what it is and where it reattaches - any help gratefully received!

 

Remove the air cleaner again and flip it upside-down

 

Yup. Attaches to the thermal sensor on the air cleaner base. The other side of the thermal sensor attaches to a vacuum nipple on the throttle body somewhere; or perhaps to a vacuum port on the manifold.

For the record, that's not a "cable" or "pipe". That's a "hose", specifically a vacuum hose. There's Genuine GM literature that has called that sort of hose a "tube", which may be technically correct, but "vacuum tube" give ENTIRELY the wrong connotation.

The thermal sensor varies the vacuum sent to the vacuum motor on the snorkel, with the general effect of keeping the incoming airstream at a somewhat stable temperature. VERY effective in eliminating/reducing throttle-body icing, somewhat effective in helping the fuel to vaporize before it gets to the cylinders. Often disabled in summer, reconnected when temperatures below 50 degrees are anticipated. Throttle-body icing is most common at 40-ish degrees F., and raining (high humidity).

Colder temps produce less icing because the air doesn't hold enough humidity. Warmer temps produce less icing because the air doesn't drop below freezing as the fuel vaporizes and absorbs heat.

 

This is awesome, thank you! Haha, yeah hose - the word was just completely escaping my brain. I'll reconnect it right now - thanks again for your help.

 

Yep......

 

.....strangest-looking IC chips I've ever seen!

 

The good ol days, , , when men were men an electrons were finally taught to behave.

Back then, a semiconductor was nothing more than a bad connection........

 

....and 400+ DC plate voltage lurked, ready to zap the unsuspecting!