problem with JPI 830 and Garmin650

[aaronk25]

Had both installed last year and reportedly the data is supposed to flow both ways between the 2 units so far I am only able to get data from the JPI to the Garmin, as the GPH shows up on the garmin under utilites.

I was really looking forward to using the Fuel Remaining at destination in the form of gallons or time and also the instant MPG that the JPI will show, that is if it receives the data. I've talked with both JPI and Garmin and they both point there fingers at the other guy.

I've used every impute/output data format possible on both units, and nothing works. Sure is nice to spend 20K on equipment just to have both companies stick their head in the mud. Any one have a new 650/750 or a 830/930 and have to deal with this?

[jlunseth]

I would go back to the installer. Were you the installer? Sounds like the connection is not right. I believe it is just an RS232 connector. I have a 430AW and a 930 and I get all that info. on the 930. Pretty seamless.

The fuel flow information is good. You do need to check it though, when you get the connection working. Instructions may be in the 830 manual. Take three trips of about 2 hours each. You fill the tanks before and after (don't have someone else do it, you need them to be exactly the same for this). Note the amount used by the fuel flow meter for the trip, and the amount used per the Avgas pump. Add up the three trips and see if you have a difference. If you have a significant difference then you need to modify the K factor (its in the manual). Mine is accurate to .1 gal. over 50 gallons, and I use it on every long trip.

Thereafter, you do need to make sure you know how much went into the tanks to start with. The JPI is "dumb" and if you reset it to Fill, it just says the tanks are full. This can be an issue on my aircraft, which has anti-siphon valves or flappers, which sometimes fool the line guys into thinking the tanks are full when they are still 5 gal. short.

[flyboy0681]

I have a JPI 700 connected to the GTN 750 and everything is working as it should. I'm wondering if your 650 is configured incorrectly. Although you shouldn't fool around with it, you can get the 650 into setup mode by pressing the HOME button while the unit powers up. This will take you to a menu where you can see all of the configuration settings. I know the fuel flow setup is found on the "RS-232 Configuration" setup page.

Looking at my installation manual I see two settings:

Fuel Flow Format 1 - ARNAV FC-10, FT-10

Fuel Flow Format 2 - Shadin 91053XM, Shadin 91204XM, JP Instruments EDM-700 or EDM-760

[larryb]

I have a GTN 650 talking to a JPI FS450.

GTN serial in 1 is set to "Fuel Format 2"

GTN serial out 1 is set to "Aviation output 1"

You should also be aware that the GTN has a serial port bug. You can only have 1 serial output set to any flavor of "Aviation output." If you have more than one serial output port configured to "Aviation output" then only the highest serial port # actually sends data. This bug is supposed to be fixed in the upcoming version 3.0 software due this quarter.

In my case, the FS450 initially did not receive data because serial output 2 is connected to my transponder, and also set to "Aviation output 1" So the transponder got data, the FS450 did not. I turned off the serial port to the transponder, it was a lower priority to me than the FS450.

Larry

[Comatose]

Mine works GTN650 to an EDM730

[aaronk25]

Thanks for the advise. I am copying my avionics shop on this thread as they may not be aware of the serial bug. I have a appointment for the 14th of this month and we will see what the deal is. I found out there isn't just 1 cable connecting the 2 there is a in and a out so I'm hopeing somthing just didn't get hooked up right. Thank you!

Aaron

[Bennett]

I have both the GTN 750 and a JPI. 830, and the combination works perfectly. I use the fuel flow as a check against my mixture settings, and while the "k" factor is spot on for remaining, fuel to destination, and the other options, (for equal topping ups), I still add a 10% conservative "adjustment" for safety

[aaronk25]

Larry you were right it was the serial port bug that was causing the error. My jpi is supposed to get its info from #1 and I have a garmin 396 on #3 and sure enough as soon as I killed the feed to the 396 the jpi 830's mpg and fuel required fields came alive.

Thanks for the heads up hopefully the software update fixes this.

[JMS]

Yes I have the same set up on a 172.Just got the fuel flow running today. I will keep an out and try to figure it out and keep you posted.