I have means of adjusting my fuel pressure on my TPI and I wan't to put the correct injector constant in my bin. Should I calculate my flow rate for the fuel pressure I have with vacuum or without? It may seem like a newb question, but I haven't been able to find the right search terms to find the answer to my question, and I've never had stock equipment to do any tests with.

 

You should set the fuel pressure and use that value for the injector flow rate with the vacuum line off. I usually just leave the engine off and hot-wire the pump. Many year harnesses had a pig-tail with a fast-on to allow easy hot-wiring of the pump.

Note that increased fuel pressure decreases the available flow from the pump.

RBob.

 

RBob, I think you're gonna single handed teach me about tuning a car one question at a time. You have all the answers. Happy New Year!