[olddog]

I have a Mass Flow system, that is designed to look like a carb. It is very similar to the picture Aussie Mike posted. I have the fuel gauge and firewall mount as well.

In talking to Mass Flow technical support. I am told that the pressure should be set at 40 PSI with the vacuum line disconected. Also that the fuel pressure should drop 1 psi for every 2" of vacuum. Indeed the fuel pressure does drop from 40 psi to 33 psi with 14" of vacuum.

On a cold start the rpms start at 1200 and drops down to 500 rpm or less. Vacuum is 14" at 1300 rpm, 10.5" at 900 rpm, and 5" when bellow 500 rpm. So as the rpms drop the fuel pressure goes up. Cam has quite a bit of overlap. Exhaust smells very rich when cold. My theory was that a stock cam would give 18" vacuum or 31 psi fuel pressure. My cam's low vacuum is allowing more fuel pressure than the ECU map is expecting and therefore is dumping too much fuel. My plan was to pull 18" of vacuum with the hand pump and start it cold, to see if it would idle propperly at the lower fuel pressure.