Help! Flow Meter Connection Mystery.

[JimW]

A few months ago I purchased a Jabiru with a D1000, but the flow meter (FT60) has never worked. Investigations showed the following:-
1) Only 0.5v on the red power supply to the flowmeter.
2) Traced the wire back to the EMS D37, and it is connected to pin 1 not pin 15, and there is continuity from the pin to the flowmeter.
3) The yellow flowmeter signal wire is connected to pin 2, and again there is continuity.
4) Pins 14 and 15 appear to connect to the D1000, but I've not actually traced them. They are also yellow and red wires respectively.
5) The flow meter is mapped to pins 14 and 15.

Questions -
a) Is this simply wrong, or could there be a reason for this?
b) Is it simply a matter of swapping pin 2 and 14 and pin 1 and 15? (But I'm concerned that there appears to be virtually no voltage on pin 15)
c) If b) is the way forward, what pin removal tool do I need?
c) Alternatively, would it be easier to map the flowmeter to pins 1 and 2?

Many thanks for any help.

Jim W

 

[jakej]

Jim

It appears that there may have previously been a legacy Dynon system installed & someone didn't know what they were doing -

Pin 1= is the voltmeter input however the Fuel flow power should be on pin 15 as you pointed out.
Basically, you need the Fuel Flow on pins 14 & 15 plus 13 for the ground as well.
My guess is that one of the yellow wires is the now redundant keep alive & the other yellow may be part of the old serial update cable.

So, in your case wires at pins 2, 10, 11, 12, 19, 23, 26, 27, 28, 31, 34, 35, 36, 37 should not have wires so can all be removed however I'd check with a multimeter just where the yellow & reds do go to, just to be sure.

HTH

Jake J

 

[JimW]

Jake, thanks for your help. One thing concerns me - there is no power on pin 1, so if I connect it to the voltmeter I assume I will get a low voltage error - unless there is only power on pin 1 when the engine is actually running?
At present the yellow wire on pin 2 is definitely connected to the flow meter signal wire.
The Y and R currently connected to pins 14 and 15 disappear up behind the panel towards the EFIS screen - I guess I will have to pull the screen out to find out where they actually terminate. According to my copy of the installation manual these should be voltmeter 1 and voltmeter 2?
The plane was only built in 2010, so the kit should be relatively recent, unless the previous owner (and builder) bought used equipment.
BR
Jim W

 

[jakej]

Jim
in 2 was the 'old' keep alive (power direct from battery bus) & is not used anymore although some harnesses still have them included, that yellow you have should go to pin 14. So for Fuel Flow you have Red to 15 as well - seems like someone has confused the wiring. :-?

Jake J

 

[JimW]

Many thanks Jake - problem is now sorted - flowmeter working fine now I've swapped the wires over - I will just need to calibrate it. Is there a usual K number to enter for a 6 cylinder Jab, or just start with the 68,000 and see how it works out? I'm working in litres - does this need to be reduced by the litres/gallon factor? However, tick-over currently showing (with K factor at 68000) 3 to 4 l/h, which doesn't seem unreasonable. Fuel gauges (2 tanks) are the Jab LED type - Is there a way to link these into the Dynon system?

Thanks again
Jim W

 

[jakej]

Jim

Good to hear that's sorted. There is no aircraft/engine specific K factor, it has more to do with variables in fuel systems types & design.
I leave the Jab Fuel Tank gauge system as is & have much more trust in using a dipstick for gauging fuel then using the fuel flow system in flight as it is the most accurate (after calibration) method of determining fuel available at any time IMO.
Someone may have tried to connect the Jabby system to the Dynon but personally I don't trust gauges, IMO they're there just as a quick reference especially the float type - capacitance type are usually much better

Jake J