Fuel Pressure & vacuum question

[cobra11182]

I just installed an adjustable fuel pressure regulator, and noticed that when I set the pressure with the engine running and no vac line, it read 40. Then I hooked up the vaccum line, and it still read 40. The car runs ok, but then when I take it out, the pressure stays right at 40, no matter how hard I hit it. Does this mean that I have no vaccum? SHouldnt that vacuum line adjust the fuel pressure with the RPM's of the engine? Also, since the vaccum line comes straight out of the intake, wouldnt the leak have to be in the line itself? THanks for any input

 

[eagle87]

When you took off your regular and replaced it, Now you might have air in the system. At any rate you should have vaccum on that line constant. Start the car blead some fuel from the scrader valve and go from their good Luck

 

[ss93cobra]

Make sure you haven't accidently forgotten to reinstall the vaccuum line at the intake, it's been done before by others and overlooked. If it is on, remove the tube and put a rubber hose on it or take your air line and blow through the factory plastic tubing/vac line to make sure it isn't restricted. Should be simple enough to fix a vac leak too. Good luck

 

[cobra11182]

but the fuel pressure should definetly change with rpm's right? and it should definetly drop when the vacuum line is conected right?

 

[Idwitheld-1`]

but the fuel pressure should definetly change with rpm's right? and it should definetly drop when the vacuum line is conected right?

If you have adequate vacuum on that line you should be able to get the line to suck and "stick" to your finger....plus you should be able to hear the sucking sound from that hose.

Increase in vacuum = decrease in FP
Decrease in vacuum = increase in FP