Red cube readings jumped

Paul K · #1 10-14-2015, 06:15 AM

I searched and didn't see any post that are the same issue I am having. For the first 2.5 yerars of operation, the fuel flow rates have been almost exactly on the mark with usage. Last month, I started getting high fuel flow warnings, up to 30 plus gallons per hour! No way can my IO360 burn that much gas and the refills (consumption) doesn't reflect using any more gas than usual. So, I checked all the electrical connections and checked to make sure the K factor hasn't changed (83). I haven't removed the unit for inspection yet but am wondering if this is actually a Red cube failure?

Paul K · #2 10-14-2015, 05:44 PM

Did another flight tonight and the totalizer was showing. 60gph in cruse. Rechecked all the connections, no joy. Next week, the cube comes off.

Brantel · #3 10-14-2015, 06:48 PM

I know you said you checked the connections but I had my factory crimped connectors fail on mine once. The wire was broken inside the crimp somehow and it was causing wild readings. From the outside you could not tell it was a bad crimp...

Paul K · #4 10-14-2015, 06:58 PM

Brian, I pulled the connections apart and gave them the tug test, cleaned them with carb cleaner (it's all I had at the moment but really works well) and reconnected them. No change in readings. I didn't test the continuity but will go back and do it.

Brantel · #5 10-14-2015, 07:06 PM

Mine had a break in the wire inside the insulation or something. It would work most of the time but in flight it would give wild readings on the very high side.

These things are really simple inside. They just provide a stream of pulses linear to the revs of the little impeller inside. The more flow, the more pulses.

If you have a bad connection like I did, the extra pulses caused by the bad connection can trick the EMS into thinking you have higher flow.

At least that was my problem.

Paul K · #6 10-14-2015, 08:08 PM

Thanks, sounds exactly what mine is doing. Will check it out.

lr172 · #7 10-14-2015, 11:02 PM

Quote:

Originally Posted by Paul K

Brian, I pulled the connections apart and gave them the tug test, cleaned them with carb cleaner (it's all I had at the moment but really works well) and reconnected them. No change in readings. I didn't test the continuity but will go back and do it.

Be sure to verify you have a good ground connection. These are very low current senders and a bad ground will cause problems. Just put on ohmmeter on the ground's crimp connection and the firewall. It should be close to 0. I would also look for broken wires where they exit the unit. If allows to move with vibration, they can break inside the insulation.

Larry

lr172 · #8 10-14-2015, 11:05 PM

Quote:

Originally Posted by Paul K

Brian, I pulled the connections apart and gave them the tug test, cleaned them with carb cleaner (it's all I had at the moment but really works well) and reconnected them. No change in readings. I didn't test the continuity but will go back and do it.

Typical failure in a crimp, beyond looseness and fraying, is corrosion. Solvents don't remove corrosion. Better to cut and re-stripe then re-crimp.

Paul K · #9 10-15-2015, 08:39 AM

Larry,

I have three spade connectors between the EIS and the Red Cube. I used them because at the time I was building, I removed the engine from the firewall several times and this was the best way to do connections at that time. Now, I am thinking about a more perminate connection. Eliminate the spade connections all together.