When I unplug the vacuum line from my AFPR should the pressure go up or down? I thought go up, however mine goes down. My brothers goes up when you unplug vacuum.
I think I found an area in my service manual that says when you apply 10 inches of vacuum to the pressure regulator the pressure should drop 3 to 10 psi. So by hooking the vacuum line up to the regualator the pressure should drop. Am I reading this right???
Well, since the "goal" of the VAFPR is to prevent a drop in pressure under heavy engine load...and vacuum goes down as load increases...then fuel pressure should increase with a drop in vacuum (removing the vacuum line), which means that when you add vacuum (replacing the vacuum line) I would expect a slight drop in fuel pressure.
The regulator/s function is to maintain a constant pressure differential across the injectors at all times. The pressure regulator compensates for engine load by increasing fuel preassure as the engine vacuum drops.
Okay just so that I am on the right page with everyone. When I plug the vacuum line into my pressure regulator the pressure drops. I gathered from the service manual that for 10" of vacuum the pressure may drop from 3 to 10 psi. As engine load increases the vacuum goes down and the pressure will rise. Is this correct?
The pressure is set at like 43 on my car with it plugged in and without it plugged in it goes to something like 40 or a little lower, I can recheck tomorrow.
I don't know other then it has done that since I have put it on. My car runs fine other then it seems kind of lazy, a little hesitant off the line.
Well I don't know then. I guess there is something wrong with my car, but im not going to worry to much it runs good. Now I don't know what Craig is going to do because everybody says that his AFPR is functioning correctly, but his car still runs like pooh.
The correct operation is the fuel pressure should rise when the line is taken off and drop when reattched.
On my 87 GN my FP was set at 43 psi line off. With line on it dropped to about 35.
I wold get a new regulator. You don't wanna have a fuel delivery problem and have it hurt the engine.
My buddy fried a piston in his 86 Buick TR because he leaned it out. His was a bad fuel pump but I never take chances when it comes to the fuel system.
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