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Fuel Flow indication not working G3X (GEA24 + FT-60 Red Cube)

Estevanb

Estevanb

Well Known Member
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Hi all,

Last week I did my fuel flow test and I realized that G3X was always showing 0 GPH for fuel flow. I use a GEA24 with red cube FT-60 as fuel flow sensor.

Troubleshooting the issue I confirmed continuity of all wires from red cube to the GEA24 connector, tried to move the connection to another connector (J244/J243) and made sure that software configuration was correct for EI FT-60 fuel flow sensor. I tested the voltages and ground on the 3 sensor wires and even bought a brand new sensor and re did all the tests.

G3X still showing zero gallons per hour. At this point, I can’t think of any other thing other than a failed GEA24 unit.

Has anyone ever had similar issue?

Appreciate any feedback.

Thanks!
 
Estevanb said:
Hi all,

Last week I did my fuel flow test and I realized that G3X was always showing 0 GPH for fuel flow. I use a GEA24 with red cube FT-60 as fuel flow sensor.

Troubleshooting the issue I confirmed continuity of all wires from red cube to the GEA24 connector, tried to move the connection to another connector (J244/J243) and made sure that software configuration was correct for EI FT-60 fuel flow sensor. I tested the voltages and ground on the 3 sensor wires and even bought a brand new sensor and re did all the tests.

G3X still showing zero gallons per hour. At this point, I can’t think of any other thing other than a failed GEA24 unit.

Has anyone ever had similar issue?

Appreciate any feedback.

Thanks!
Click to expand...
Installation manual rev: AW pg 26-3 wiring ?. Checked front/ back side of D-sub connector correct pin ?. Flashing green led on GEA 24 yes ?
Contact Garmin for advice. [email protected]

Good luck
 
When my FF stopped showing on my G3X it was a bad red cube. A new one fixed the issue. They will rebuild the red cube for you cheaper than a new one. I just got a new one to save the time.
 
Avanza said:
Installation manual rev: AW pg 26-3 wiring ?. Checked front/ back side of D-sub connector correct pin ?. Flashing green led on GEA 24 yes ?
Contact Garmin for advice. [email protected]

Good luck
Click to expand...
Hi, yes pins triple checked and also tried to move connections to alternate position in J244
J243.21 FUEL RETURN (shared w/Pin 37, J244 connector) In

J243.23 FUEL FLOW (shared with Pin 36, J244 connector) In

Still no joy.. GEA flashing green, all LRUs fully functional. no CANBUS issues.

Contacted Garmin for the troubleshooting and now I have a replacement GEA24 on the way.

Thanks for the comments
 
rockwoodrv9 said:
When my FF stopped showing on my G3X it was a bad red cube. A new one fixed the issue. They will rebuild the red cube for you cheaper than a new one. I just got a new one to save the time.
Click to expand...
Took the same approach. bought a new red cube and replaced mine. no joy. still no fuel flow indication. G3X support recommended replacing GEA24 now..
 
Inspect the wiring coming from the red cube. Years ago, an experimental was brought into the shop I was working for with a "no fuel flow" indication squawk. Wiring was very thin and found to be frayed due to improper support. (The wiring was not secured and was vibrating until it broke.) The break was far enough from the red cube that I could splice it.
 
I want to chime-in here.
I also have a problem with the fuel flow indication on GEA24.
In my case I have EFII system32 installed. Fuel flow indicates on the Controller but not on the G3X.
I have checked (quadruple checked) all wiring, so it is time to start doubting the GEA24 itself.
 
JoopSJ said:
I want to chime-in here.
I also have a problem with the fuel flow indication on GEA24.
In my case I have EFII system32 installed. Fuel flow indicates on the Controller but not on the G3X.
I have checked (quadruple checked) all wiring, so it is time to start doubting the GEA24 itself.
Click to expand...
Did you reach out to Garmin? Solved the issue on your case already? Lets keep in touch I will update you once I get the new GEA24.
 
JoopSJ said:
I want to chime-in here.
I also have a problem with the fuel flow indication on GEA24.
In my case I have EFII system32 installed. Fuel flow indicates on the Controller but not on the G3X.
I have checked (quadruple checked) all wiring, so it is time to start doubting the GEA24 itself.
Click to expand...
Assume you are not using a red cube. As long as the blue wire is connected and configured should work.
 
Last edited:
If you don't know who's miss-behaving in this situation, the gold standard is to find somebody who has an oscilloscope and look at the signal going back into the GEA 24. You should see pulses when there is fuel flow. To be most effective, the closer to the GEA 24 to look the better to reduce the possibility of the red cube putting out fine pulses but there's a wiring issue on the way to the GEA 24. Could even be a GEA 24 connector pin not properly seated. I would take the shell off P243 and push a thin wire or very thin dental pick into the pin 23 contacting the pin inside (fuel flow pulse signal here) and look for the pulses (with respect to ground). Pulses there? Bad GEA 24. No pulse? Check at the red cube. Pulses there? It's a wiring issue. No pulses? It's a bad red cube. Don't need to run the engine - just disconnect at the flow divider and run a hose into a jar and run the electric fuel pump. This way not taking pot shots at the red cube and GEA 24 with a chance of it still ending up wiring!
 
N49ex said:
If you don't know who's miss-behaving in this situation, the gold standard is to find somebody who has an oscilloscope and look at the signal going back into the GEA 24. You should see pulses when there is fuel flow. To be most effective, the closer to the GEA 24 to look the better to reduce the possibility of the red cube putting out fine pulses but there's a wiring issue on the way to the GEA 24. Could even be a GEA 24 connector pin not properly seated. I would take the shell off P243 and push a thin wire or very thin dental pick into the pin 23 contacting the pin inside (fuel flow pulse signal here) and look for the pulses (with respect to ground). Pulses there? Bad GEA 24. No pulse? Check at the red cube. Pulses there? It's a wiring issue. No pulses? It's a bad red cube. Don't need to run the engine - just disconnect at the flow divider and run a hose into a jar and run the electric fuel pump. This way not taking pot shots at the red cube and GEA 24 with a chance of it still ending up wiring!
Click to expand...
I don't have an oscilloscope handy but I did confirm that there is an oscillatory signal at the signal wire when fuel flows. When no fuel is flowing the signal wire is steady 10v. Same behavior on 2 different sensors.

I have a replacement GEA on the way but I haven't tried re doing the pins on the wires. But I think this is not the issue as I have clearly continuity in all 3 wires.

Thanks for the thoughts. if the new GEA does not solve the issue I will definitely have to find an oscilloscope.
 
rockwoodrv9 said:
When my FF stopped showing on my G3X it was a bad red cube. A new one fixed the issue. They will rebuild the red cube for you cheaper than a new one. I just got a new one to save the time.
Click to expand...
EI flow transducers cannot be rebuilt. If verified to be inop, the transducer must be replaced.
 
Do you by chance have the GEA “RPM 2” input wired and configured as a discrete input? I know it sounds like a random question, but I had the same problem and traced it to this cause after trying a replacement GEA and wiring a borrowed red cube directly to the fuel flow pins.
 
jwyatt said:
Do you by chance have the GEA “RPM 2” input wired and configured as a discrete input? I know it sounds like a random question, but I had the same problem and traced it to this cause after trying a replacement GEA and wiring a borrowed red cube directly to the fuel flow pins.
Click to expand...
I actually do! What was the solution in your case? Can’t use rpm2 as discrete input at the same time we use fuel flow?
 
jwyatt said:
Do you by chance have the GEA “RPM 2” input wired and configured as a discrete input? I know it sounds like a random question, but I had the same problem and traced it to this cause after trying a replacement GEA and wiring a borrowed red cube directly to the fuel flow pins.
Click to expand...
Joshua,

You nailed it. The issue is a software bug! The RPM2 is used as discrete alarm, fuel flow stops working. I worked on the scenarios with Garmin and they were able to replicate the issue. It will be fixed on the next G3X SW release.

Thanks @jwyatt
 
Estevanb said:
Joshua,

You nailed it. The issue is a software bug! The RPM2 is used as discrete alarm, fuel flow stops working. I worked on the scenarios with Garmin and they were able to replicate the issue. It will be fixed on the next G3X SW release.

Thanks @jwyatt
Click to expand...

Glad you got it sorted, Estevan! I found this back in the spring and had a back-and-forth with Garmin, as well. Looking forward to the software fix and being able to use the discrete I have wired into RPM2.
 
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