[Tiara Open] 454 XLi Low voltage at electric fuel pump

[Mtgates44]

Have been troubleshooting fuel problems on my 1996 Tiara 3100 with 454 XLi s.  Measured voltage at fuel pump.  When turning key only get 10.5 volts at starboard fuel pump.  Measure 12+ volts at port fuel pump.  Anyone experienced this before?

[Mtgates44]

Problem was not anti-siphon valve.

[hiccup]

Thanks for updating the thread, it's great to hear how the problem was fixed!

[Mtgates44]

5/4/2025
Update

It was not the anti-siphon valve.  Thought it was the ignition/fuel pump relay because when I replaced the relay the engine started.  However, after running a few minutes it shut down again.  The engine would restart when reset the tripped 10-amp circuit breaker on the black box bolted to the exhaust manifold riser.  

Determined it was a faulty oil-pressure switch.  When it fails, the computer sends a code to limit voltage to the fuel pump.  That fixed the problem temporarily.  Now the engine will run fine then occasionally die.  Wait a few seconds and the engine will restart.  It will then run again for various periods of time...minutes to hours before dying again....still troubleshooting.