TF pickups with TPI engine photos wanted.

[oossuuu754]

Originally Posted by Coupeguy2001

Ossiu,
The reason your air is going hot to cold is because your system runs on vacuum.
When you first start it up, the vacuum is high at idle. when you give it gas, the vacuum falls off, opening the heater valve. when you get up to speed, and at cruising speed, the vacuum is steady, and the heater valve closes.
Try using a coffee can with a hole poked in it to let the coffee out, then make yourself an adapter where you can solder the hole in the coffee can with a washer with a small hole in it and just on the lid, solder a 1/8" tube through it and run the vacuum from your engine to a tee type vacuum check valve mounted close to the can, and the other end of the tee to your heater/AC controls.
That way, your vacuum sucks on the can, the vacuum goes to the heater controls, and the check valve keeps the vacuum in the can from escaping back into your engine when it is shut off.
The can acts like a vacuum reservoir.
Is it possible you got a vacuum reservoir with the donor car? check it out.

I sure I can find a vac reservoir and the pick a part. Another suggestion was that I should get a old heater (petcock) valve and install it on the heater hose from the engine to the unit.

Thoughts?