I am running a mallory regulator with a return line to my carb, and am still using the tbi pump. At idle i am between 6 and 7psi, if i get on it more than half throttle it drops to 4psi. The real problem is when i floor it my pressure immediately goes to 0. I have a nordskog digital fp gauge to monitor my fp. What could be causing this, what should i check? All opinions and suggestions are apreciated.

 

i'd say your filter is plugged or the pump is going. i have a carb so i'm not familar with your pump but my holley blue maintains 7 psi at wot

 

Flow test your pump to an open container. Measure the flow delivered from the pump in 15 seconds, then multiply by 240 to get the GPH delivery. If you're not getting 30 GPH, you have a pump, filter, line, or pickup issue.