JPI FluelFlow FS450 odd readings

[agidi]

Hello guys, one for the Gurus...

I´ve had a trusty FS450 running on my Cessna 182N for years now. Spot on readings.

Today, just after takeoff, the reading went from standard 15gph to 10, 8, 5, 0.
The engine did not stutter or loose RPM. Thank God!.

it stayed at zero for some minutes, then jumped to 16gph, then back to standard flow , then back to 0.

I thought it could be debris on the waterwheel sensor, then i remembered those are transducer types.
No moving parts?

What´s the standard troubleshooting procedure here?
Could it be debris? Electrical connections?
Please advice, all comments and suggestions are welcomed.

 

[flyingron]

I'd suspect the electrical connection. Frankly, the one thing JPI is lacking on is the connector quality on the back of the units. I keep losing my GPS feed to the 830 (periodically I lose the MPG and fuel-to-dest for a few minutes and then it comes back).

 

[Marauder]

High likelihood it is the fuel flow transducer. Mine failed this Spring and I had erratic readings. Sometimes it would show fuel flow normally and then stop completely and show a zero. Since I have two devices reading the fuel flow (a JPI 830 and an EI FP-5L) I saw this on both.

The transducer has a little wheel inside a housing that rotates as fuel flows past it. It can get stuck. If it is the transducer, you may need to redo the K factor calculation for your plane. There will be a value on the replacement transducer but you will most likely need to fine tune it.

 

[agidi]

So It does have moving parts, I thought it was an ultrasonic o touch less kind of sensor; and I'm guessing the wheel does not stop the fuel flow when it does get stuck?
It does not occupy 100% of the tubing or flow body?
I have not seen a cutout or schematic specific for the jpi.

Can it be serviced? Back washed etc, remove debris. .?

 

[Bill Faught]

Had same problem with Fuel Flow on a Bonanza IO-520. New transducer fixed it. Was told the bearings wear out and cause erratic readings. No flow interruption as the turbine doesn't restrict the flow much if at all.
Bill Faught

 

[Marauder]

So It does have moving parts, I thought it was an ultrasonic o touch less kind of sensor; and I'm guessing the wheel does not stop the fuel flow when it does get stuck?
It does not occupy 100% of the tubing or flow body?
I have not seen a cutout or schematic specific for the jpi.

Can it be serviced? Back washed etc, remove debris. .?

Flow can get by with an impeller that is frozen. I was told that it was not worth trying to clean it since they just wear out. Mine last 20 years before it died.