Hey guys. I have an 89 formula 350. Used to be a tpi car. After I put my last engine in, whenever the heat was on, the hvac controls hissed. Come to find out that I had my heat diverter valve line and hvac line mixed up. I fixed that, and my hiss stopped, and now my blend door works again. Great!

The problem I have now, is that when I put the slider to Heat, the car runs rough and its a b!tch to start off in 1st gear because it wants to stall. I don't hear any vacuum leaks, and im not sure how these lines should be properly run.

As stated, my hvac controls are working now, and my coolant diverter valve vacuum line has been blocked off, as it should be.

Where do I go now?

 

nobody is familiar with the firebirfd hvac controls?

 

nevermind me....

Apparently if you hook the heat control, and map sensor vacuum lines together, the car wont run.

When I turned on the heat, it took vacuum away from the map sensor, and the car ran like crap. Its all fixed now, car runs great. Learn from my mistakes! lol