I have a universal fuel reg with gauge with in and out and then the small vacuum pipe. All is connected except for the vacuum pipe.NOW can this cause probs or do i have to drill and fit pipe to manifold.does it cause a jerk when you put foot etc,etc. google shows a bit but there are also others that show you can leave it open. I already have a prob with petrol flowing out vac pipe so i suspect pressure was to high and i damaged the diaphragm. I also read pressure should be 40--43psi.Can anybody with know how give a bit of info. thanks

Can it cause problems if you do not connect the vacuum hose?

40-43 PSI pressure depends on which fuel injection system you are running. Some require more, some require less. Which EFI setup are you using it with?

Quote:That is cause by a cracked rubber diaphragm. Don't connect it to vacuum unless you fix it first.

More to that point, if you have fuel comming out of the vacuum fitting, that part is bad. That type of regulator uses vacuum to change fuel pressure.

DD -- ok yes i forgot to say -- it's 38mm t/bodies from zx6 kawa and zx10 injectors with the vw fuel pump and as for the use of the reg like it is well no i have not cos as i've said i suspect i have damaged the diaphragm. The second ans i got was also s/thing i heard---that the vacuum pipe reg the pressure. This is precisely why i'm asking.Why do some say fit pipe and others say you can leave it open.Is it a case of regulating on top and have the pressure lower with vacuum pipe allowing for adjustment.how you gonna know what pressure is safe to run at?Rgrinder yea i realise it's buggered now but it was new and work perfectly---pressure was prob to high-- suppose i'll have to get anew one--reckon no parts for the universals