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Topic-icon fuel pressure, higher

  • BILL CHISHOLM
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1 month 4 days ago #1780

All of a sudden, my last few flight I've had a higher than normal fuel pressure reading in cruise, landing and final taxi than historically. The first time I thought it was due to 1.5 hours in -35F air, but it's the same now. Since 2010 it was historically ~1/3 into the green of the fuel pressure gauge and would ever so slightly bump up if the electric boost pump was engaged when flying and drop into lower green zone in idle, but back to 1/3 green with the boost pump taxiing; as per the POH instructions boost on taxi and TO/Land.
Now it read 2/3 to 3/4 in the green when flying and landing and taxiing and jumps to 40 (upper green/red line) if engaging the boost pump. So I resisted the use of the boost pump landing & taxi. Electric boost pump seems to be operating normally.
Engine runs normally, no power loss. Fuel flow is normal. JPI EGTs/CHTs normal.

Any ideas were to look?

PA32-300 1971
IO-540 KIA5
Gami injectors
Shadin fuel flow
Romec fuel pump RG 17028D/m s/n B-9480, overhauled 03/2017
Fuel pressure gauge is marked as 0-18 yellow, 18-40 green & 40+ red

I'm in the process of converting the right mag to the Electroair system with my AME. So haven't yet hooked up an auxiliary gauge to test the actual fuel pressure.


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1 month 1 day ago #1781

One thing that can cause higher FP indications is a partially blocked fuel injection nozzle. Makes sense; pump is putting out same pressure but there's a restriction in the delivery line.
Suggest you remove and clean injectors; making sure that they all get back in the correct cylinders.
I know there should be an indication of less fuel flow on the EGT and CHT but, the initial Troubleshooting fix is clean injectors.
If you're reluctant to do that, put a direct reading guage on the FP line to see what the fuel pressure is.
Have you contacted Shadin??
Let me know what you find.
Steve

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