There are 2 censors on the back of the Actual Tpi manifold not the plenum and i know one of them is the coolant temp But the is a Big one right next to it and i was woundering if any of you could tell me what it is.

 

u must mean the FRONT of the base correct? yes,1 is the CTS (coolant temp. sensor) and the other is IAT (intake air temp.) i THINK...im sure some1else will come in and clear this up.

 

CTS is up front near the TB. At the rear....... I can only think of one sensor back that far- the oil pressure switch which actually screws into the BLOCK just a tiny fraction of an inch behind the back of the intake manifold, just to the driver's side of the distributor.

Intake Air Temp sensor is screwed into the bottom of the intake plenum.

 

on the front of a 86 base is the CTS and the cold start injector switch

 

That right Thanx man its the cold start switch the only thing i didnt think of Ill be danged. Than alot guys