I have a 2000 Ultra Classic and the manual says my supply line fuel pressure should be 43.5 psi. My supply line psi is a solid 51 psi when the bike is running. I have a power commander, big sucker intake and the baffles in my tail pipes were removed. Is 51 psi too much? When the engine is not running and I click the run button to turn on the fuel pump the fuel pressure regulator opens at 43.5 psi and the pressure goes down to 0 shortly after it opens.

FYI - I started poking around the bike because it is sometimes difficult to start and occasionally the throttle body makes a popping noise when I am trying to start the bike.

Any thoughts or suggestions would be appreciated.

 

Yes it is possible to have too much fuel pressure. If the spec is 43.5 psi and you're observing 51, something is not functioning properly. Fuel delivery has to be 100% rock solid on fuel injected vehicles because the amount of fuel injected when the injector is fired depends on that pressure being where it is supposed to be. Are your plugs fouled? Does the engine run rough, especially at idle?

 

Don't know about your bike but mine has a fuel regulator that opens up and releases excess pressure and gas back into the tank. if the pressure exceeds 50 psi or so.


Ignore this. Ronnie's parts catalog shows a regulator for my bike but not your 2000 UC

 

Yes, the plugs are what the manual calls carbon fouled. Not sure the engine runs rough at idle. It is a Harley so it vibrates at idle.

 

The fuel pressure regulator for the 2000 ultra is not in the tank like the more recent models. It’s actually on the throttle body so you have to look at the throttle body parts diagram. The one on my bike is brand new. I just replaced it last year.

 

That sounds like rich fuel mixture to me. You definitely want to get that fuel pressure condition corrected.