BBK adjustable fuel pressure regulator

stevesLX

Member
Nov 12, 2006
373
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16
cincinnati
I went out and bought a BBK AFPR and the instructions say to disconnect the vacum line from it and plug it and adjust the fuel pressure. Well I did that and when I hook the vacum line back up the pressure drops. For instance I set it around 35 with the vacum line disconnected and when I stuck the line back on it drops the needle on my pressure guage down to around 29 - 30. Is that what is suppose to happen or what. Something else I noticed is if I rev it up the pressure goes up initially and then it goes down to around 25 or so and stays there until I let off the throttle cable. I have 24 # injectors. I am not really sure where I should have the pressure set but I am curious about the whole vacum line deal and whats right and wrong.
 
The pressure is supposed to drop when you reconnect the vacuum line, that's why they have you take it off in the first place for setting the pressure with a gauge.
 
The pressure drop into the 20's should only last a second. If it lasts longer, that indicates an issue.

Good luck.