Hello all. I've owned my 84 Z28 H.O for about 2 months now. Haven't driven it too much because I had to put a tranny and new carb on. I'm running hotter than I should be. I DO have an air dam in place. I know I'm running a little hotter than I should because I find that some wire loom has melted. The temp gauge never goes over 220* though. The car has a mechanical fan that is always on, I guess in an attempt to keep it cool. So I got an electric fan and a painless wiring harness. The harness includes a thermostat to turn the fan on and off. It says it screws into the intake manifold or head. Which one? I'm guessing the thermostat housing. The housing has 2 plug type things sticking out of it. What are they? Is 1 of them the ECT? There are no wires running from them and my friend who put the tranny in said this car used to be computer controlled. It certainly seems that way. And if that is true, that explains the mechanical fan that is on all the time, since there is no ECM nothing is telling the fan when to come on. Other clues that tell me this was an ECM car; smog pump bypassed, metal tubing on the exhaust manifolds (1 per cylinder) that almost look like runners for a fuel injection system. I found what looks like it could be a map sensor. And I have no EGR. So was this TPI or TBI or carbed with an ECM? Knowing that should make work easier. Anyway, I just need some insight on this. First, was this an ECM car at one time? What are those things on the thermostat housing? And where exactly do I install the thermostat for that wiring harness? . Just trying to figure this car out. The fact that this car has been modified is making that much harder Thanks in advance!

 

If there's evidence of a MAP sensor, it was computer controlled.

You can use either a port in the head or the stat housing for your switch. It can turn the fan on without the computer.