[[email protected]]

My fuel flow indication from a red cube transducer to a Skyview system have just started to intermittently display a zero flow drop out. No fluctuation of the flow is observed, just an apparent complete loss of signal to zero for several minutes then back to normal.

Any similar experience or troubleshooting thoughts?

 

[miyu1975]

Have not seen this on mine..., assuming your engine didn't die when FF went to 0. I guess I would start with the wiring checking for loose ends, bad crimp..etc.

 

[[email protected]]

no erratic indication...

Have not seen this on mine..., assuming your engine didn't die when FF went to 0. I guess I would start with the wiring checking for loose ends, bad crimp..etc.

Thanks Ryan, no engine fluctuation or erratic indications typical of a connection issue... I suspect that it is a transducer failure within the red cube but will trace the wire and connection side of things.

 

[Brantel]

Had a similar failure.

It was the factory crimped connection.

 

[[email protected]]

interesting...

Had a similar failure.

It was the factory crimped connection.

Thanks Brantel, do you recall which wire you found the failure on? I replaced all of the factory ends with d-sub pins and wrapped them with heat-shrink...

Electrically, I am seeing no jump or erratic signal... simply a removal of the signal voltage to 0.0 indicated for several minutes then a return to normal function.

You did not see any erratic fluctuation in the signal or flow?

 

[Brantel]

Mine was in the signal wire. It was reading all over the place then it just stopped.

The wire was still in the connector but the wire inside the insulation was broken.

 

[pvalovich]

Red Cube

I had an issue with random fluctuating fuel flow indication (no change in engine performance). Called EIS and was told to crimp the h*ll out of the conectors. Used long nosed pliers and a lot of force on all three wires. Problem solved - although I still don't know which lead was the culprit.

 

[[email protected]]

not a fluctuating reading...

I had an issue with random fluctuating fuel flow indication (no change in engine performance). Called EIS and was told to crimp the h*ll out of the conectors. Used long nosed pliers and a lot of force on all three wires. Problem solved - although I still don't know which lead was the culprit.

Thanks pvalovich, as it turns out, I am not seeing a fluctuating or erratic reading... it is normal and regular with expected stability and function and without any power change or other flight change of any kind the signal will drop to zero volts and the indicated fuel flow will drop to zero.. a few minutes later normal function returns.

I inspected the connections and crimps and they do not appear to be the source of the observed loss of signal voltage

 

[dmaib]

Is your EIS Grand Rapids? If so, it might well be the transducer. I've had to replace one or two fuel pressure and oil pressure transducers in 5 1/2 years. Symptoms sound identical.

 

[BSwayze]

Stephen, I'm curious about how you installed it. I don't recall seeing a photo of where/how you mounted it. Is it on the engine, the firewall, or inside the cabin somewhere? I finished mounting mine on the firewall a while back, after much deliberation and research. I'm curious if this may have anything to do with it.

 

[Gash]

Had the same problem

I had the same problem. It was a bad crimp on the signal line. Fixed it and haven't had any problems since.

 

[[email protected]]

follow up FYI

Okay, I am happy to have my fuel flow reliably working again...

I suspected a faulty red cube or perhaps something with my engine monitor module given the steady state signal failure observed (normal reading that would drop to zero for minutes at a time then return to normal - NO erratic readings), however, the overwhelming failures are associated with the crimped connection where vibration can 'jiggle' all but the most robust joins.

I contacted EI and they suggested trying their new high vibration over-lap connectors that they are currently providing with their units. If that did not cure the issue, they suggested that the flow wheel could be getting hung up and I might run some cleaner through it and tap on the unit to see if any debris comes out...

The connectors are really neat and I installed them.

No fix though...

I pulled the unit and inspected the flow wheel and found it to be free and running smooth... used some cleaner (MEK) and tapped on the unit... nothing but clean MEK...

No fix...

I had an extra engine module sitting around and swapped it out...

No fix...

Pulled the D-Sub pins at the engine module and closely examined them... just fine

No fix...

Bought a replacement red cube from ACS...

FIXED

 

[Bob Axsom]

Just installing mine

I assume you have been running with yours for sometime (like when I saw you in various races last year. Thanks for sharing the failure and cause - I'll file that away for future reference. It is good to read that even though the red cube failed intermittently it did not cause the fuel supply to be interrupted.

Bob Axsom

 

[rzbill]

The flow wheel does not go all the way into the flow passage. It just picks up an edge of the fuel flow and spins accordingly. So, it is somewhere between unlikely and impossible for failure of the sensor itself to completely block the fuel flow.