Fuel Line PSI Excessive / 2015 Arctic Cat XR 550 XT (Fuel Injected)

[DonB]

Had fire start in muffler due to failing fuel pump &/or fuel pressure regulator.  Must I spend the $750+ for a new assembly from Arctic Cat?!?  Here's what I've tried so far.

• Replaced fuel pump & regulator - both from Quantum.
• PSI is 60 rather than the 42 the dealer advises it should be, so problem persists.
  •  I've now twice replaced the Quantum regulator & discussed w/ Quantum.
  • They advise that they don't have an alternative regulator that would bring PSI down to 42.
• I've tried several in-line, adjustable pressure regulators but they either didn't work or I couldn't get a constant pressure from them.
  • FYI, I've only tried the adjustable regulators for Fuel Injected engines however, it seems that they require vacuum to function properly. 

When I can temporarily get the PSI right, everything works great.  Anyone else ever dealt with this problem, and, if so how did you fix it?  Perhaps I should adapt the fuel system to include a gas tank return line?

Any insights are greatly appreciated, Don

[Mech]

If that bike has a barometric pressure sensor that calculates altitude, I'd check that sensor was communicating with the ecu properly.

The dash gauge will show you what it's reading if you put it into diagnostic mode..  I think.

I'm reading an 2016 Alterra 550 manual..

[DonB]

Thanx, Mech.  I'll take a look.