I'm swapping from a TBI to a TPI system on a 1993 Caprice Wagon. I'm a little bit confused on the coolant hoses to make sure all the return lines are correct. On the Caprice TBI, a line went directly to the heater core inlet to supply it from the back on the block. On the TPI system it would seem possible to take the outlet from the Throttle Body to the inlet of the core simply enough. But... if I route it directly, wouldn't I be stopping the flow thorugh the throttle body unless the heater is on? Did F-bodies use some sort of diverter or valve to allow the throttle body coolant to return to the radiator but bypass the heater until needed? I'm at a loss for routing and could use some help here.

most people bypass the throttle body coolant line on tpis,atleast i did and most people i know.All it does is heat up the throttle body in turn heating up the air going through it.Iwas told it was for colder climates so the throttle blades dont get stuck or frozen shut.I live in mississippi where it rarely gets below freezing and ive had no problems.

I live in New York. At this point I am not considering bypassing the TB.

As I stated clearly in the original questrion, I 'd simply like to know what existed on the original systems.

The question was "Did F-bodies use some sort of diverter or valve to allow the throttle body coolant to return to the radiator but bypass the heater until needed?"

Thank you for the idea, but the original question remains unanswered.

You are correct they do use a diverter valve to redirect hot water around the heater core when the A/C is on. The stock path is from intake nipple to driver side throttle-body, out passenger side of throttle body to diverter valve, and the diverter has hoses going to the heater core and return on the radiator. If you will look at my post from last week, http://www.thirdgen.org/techboard/co...le-bypass.html (Diverter delete, throttle bypass mod) ,you'll see how I intend to prevent hot water from going thru the thottle-body and heater core with one shut-off valve (during the summer time).

So if I understand it correctly, when the A/C is turned on, then there was some sort of solenoid or small motor attached to the diverter which would activate, switching the valve, bypassing the core and returning the coolant directly to the radiator.

My worry was that the coolant would not flow though the heater core at all. I can see that having The "Summer Bypass" couls also be handy, but my TBI motor/pump never had that outlet on the top of the pump that you've mentioned.

Yes the diverter returns it to the radiator, but I think that is vacuum operated.
Why would you worry that coolant will not flow thru the heater core? do you mean at all times?
About the water pump outlet, you could just send it back to your radiator or use a different pump (mine is a Flowkooler).