My fuel pressure is dropping (<12 psi) approximately every 30-60 minutes in flight. I can turn the boost pump on and it returns to normal (25-30 psi). It’s not just a bad sensor, because the engine has stumbled before when this happens. This is a fuel injected Aerosport Power IO-375 with 400 hrs.
I have done the following troubleshooting:
1. Checked every fuel fitting dozens of times. No loose fittings or fuel leaks observed.
2. I talked to Tempest at OSH and they said, “Our pumps done fail like that. They work or they don’t.”
3. Cleaned and inspected the fuel servo filter. No issues found.
4. Cleaned and inspected the AFP filter. No issues.
5. Talked to Don at AFP and he said, “Turn the fuel selector valve off put 10 PSI air pressure at the firewall fitting. Bubble check all connections going back to the selector valve.” No leaks found.
6. Both tank vents are clear and working.
This seems to only happen when the tanks are full. But it also happens on both R and L tanks making me think the issue is somewhere from the fuel selector forward.
Before I start replacing parts, what else can cause this?
Thanks,
Chris
I have done the following troubleshooting:
1. Checked every fuel fitting dozens of times. No loose fittings or fuel leaks observed.
2. I talked to Tempest at OSH and they said, “Our pumps done fail like that. They work or they don’t.”
3. Cleaned and inspected the fuel servo filter. No issues found.
4. Cleaned and inspected the AFP filter. No issues.
5. Talked to Don at AFP and he said, “Turn the fuel selector valve off put 10 PSI air pressure at the firewall fitting. Bubble check all connections going back to the selector valve.” No leaks found.
6. Both tank vents are clear and working.
This seems to only happen when the tanks are full. But it also happens on both R and L tanks making me think the issue is somewhere from the fuel selector forward.
Before I start replacing parts, what else can cause this?
Thanks,
Chris