Speed Merchant Posted July 28 Report Posted July 28 I had a JPI 930 installed in my 1984 201. The left and right fuel gauges show empty when the fuel total indicator shows 18 gallons left. I determined this carefully by the amount of fuel it took to top off the tanks. The shop that did the calibration apparently did not correctly complete the calibration. I am wondering if anyone on MooneySpace who installed a 930 could share their calibration data with me. The calibration starts by draining the fuel and then filling the tanks progressively and recording data on the JPI to develop a calibration curve. Any help would be appreciated. Quote
0TreeLemur Posted July 28 Report Posted July 28 According to the instruction manual, you must do the calibration for each aircraft due to peculiarities with tank geometry and sender types and properties. The procedure is well documented in the installation instructions. I've done on two different Mooneys. Rather than remove the sump drain valve, which in my experience is asking for problems, I returned from a trip with about 10 gallons on one side and the other side ran empty. While filling the empty tank, I recorded numbers on the JPI (setup menu) for empty, 1/4, 1/2, 3/4 and full fuel levels. Then I siphoned all the fuel I could out of the tank with 10 gallons remaining, went flying, ran it dry, and repeated the procedure for that tank. It's not too bad, a fun day at the airport. If my J had a prop on it, I'd fly down and help you with it! 2 Quote
Speed Merchant Posted July 29 Author Report Posted July 29 I was hoping someone might have these readings from the setup for their bird. If there was a difference because of different sending units or floats the difference in volume would be very small. If I can't find some existing readings I will have to use a method like yours. Thank you for your post. 1 Quote
Aerodon Posted July 29 Report Posted July 29 It's not that hard to remove a drain valve. Get a couple of new ones, they tend to corrode and start leaking anyway. I'd rather have the proper amount of unusable fuel, the proper zero reading in the proper attitude. Setup a spreadsheet and plot a chart for both left and right sides. Use this for cross correlation to the fuel totalizer, and to make finer adjustments in the future. Aerodon Quote
ArtVandelay Posted July 29 Report Posted July 29 Just be careful not to over tighten the fuel drains. Quote
Pinecone Posted July 29 Report Posted July 29 To do it right, you need to level the plane also. Quote
laytonl Posted July 29 Report Posted July 29 I can send you my data when I’m back home. However, you really need to do your own calibration and it’s a simple process. After draining the tanks and reinstalling the drain sumps, It only took about 30 minutes to do the calibration. Lee Quote
Speed Merchant Posted July 30 Author Report Posted July 30 21 hours ago, Aerodon said: It's not that hard to remove a drain valve. Get a couple of new ones, they tend to corrode and start leaking anyway. I'd rather have the proper amount of unusable fuel, the proper zero reading in the proper attitude. Setup a spreadsheet and plot a chart for both left and right sides. Use this for cross correlation to the fuel totalizer, and to make finer adjustments in the future. Aerodon Thanks for the suggestion and your post. Quote
Speed Merchant Posted July 30 Author Report Posted July 30 17 hours ago, ArtVandelay said: Just be careful not to over tighten the fuel drains. Thanks I will be careful. Quote
Speed Merchant Posted July 30 Author Report Posted July 30 12 hours ago, Pinecone said: To do it right, you need to level the plane also. Thank you for the suggestion. I appreciate it. Quote
wombat Posted July 30 Report Posted July 30 Funny, I was just about to make a post asking if fuel tank calibration should be done in wheels-level or aircraft-level attitude but decided to search first! Quote
Speed Merchant Posted July 30 Author Report Posted July 30 17 hours ago, ArtVandelay said: Just be careful not to over tighten the fuel drains. Any idea what the part number for the fuel drain? Quote
laytonl Posted July 30 Report Posted July 30 This is what I use, F391-53-S https://www.aircraftspruce.com/catalog/appages/f391.php lee Quote
mhrivnak Posted July 30 Report Posted July 30 When calibrating the 900 with my factory senders, I recall taking measurements at 8 gallon increments. On one side, the number barely moved after adding the first 8 gallons, but a little shake of the wing got it to read appropriately. I don't know if that's common, but maybe your senders didn't get the encouragement they needed to move off of the empty position. Quote
0TreeLemur Posted July 30 Report Posted July 30 On 7/28/2024 at 10:28 PM, Aerodon said: It's not that hard to remove a drain valve. Normally, it is not hard to remove a drain valve. That said, removing them can create unanticipated problems that one might wish to avoid. For instance, unbeknownst to me the steel bracket inside the left tank that retained the sump valve on my C was corroded. Removing that valve caused that bracket to fail. That was a time consuming repair. In the spirit of risk mitigation I'd suggest that if there is a way to do the calibration without removing the valve, do that. Particularly in an older Mooney... It's easy to run a tank dry too. Plus you get to fly while doing it. Quote
Pinecone Posted July 30 Report Posted July 30 10 hours ago, wombat said: Funny, I was just about to make a post asking if fuel tank calibration should be done in wheels-level or aircraft-level attitude but decided to search first! For the fuel gauges, I calibrated level. For my fuel sticks, I calibrated in wheels level (ground attitude). There is a difference in the readings. Quote
Carl Everitt Posted July 30 Report Posted July 30 Can somebody point me in the right direction for a procedure for leveling the aircraft, we have CIES probes coming and the POH is pretty vague (and of course no leveling screws). According to the POH the M20E carries 52 gallons, is there unusable fuel ? Thanks, Carl Quote
Speed Merchant Posted July 31 Author Report Posted July 31 23 hours ago, laytonl said: This is what I use, F391-53-S https://www.aircraftspruce.com/catalog/appages/f391.php lee 23 hours ago, laytonl said: This is what I use, F391-53-S https://www.aircraftspruce.com/catalog/appages/f391.php lee Thanks Lee I appreciate your help. Quote
LANCECASPER Posted July 31 Report Posted July 31 10 hours ago, Carl Everitt said: Can somebody point me in the right direction for a procedure for leveling the aircraft, we have CIES probes coming and the POH is pretty vague (and of course no leveling screws). According to the POH the M20E carries 52 gallons, is there unusable fuel ? Thanks, Carl Section 2-10 of the Maintenance Manual will spell it out for you. If you don't have one - go to the downloads section above. Quote
ArtVandelay Posted July 31 Report Posted July 31 This is what I use, F391-53-S https://www.aircraftspruce.com/catalog/appages/f391.php leeThese have a stiff spring, enough I thought it could break the plastic on the gnats jar, there’s another brand (Curtis?) the spring is not so stiff. Quote
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