Fuel pressure reading wrong

[Derek_Liston]

Sorry if this topic has been previously posted. My Skyview fuel pressure was reading was reading 19.5psi without engine running. Jabiru should have around 3psi but with engine running I was reading about 30psi which was clearly wrong or carburettor would have flooded. I checked and found that I had the wrong Pt No installed on Skyview. I changed it and am now reading CFG? C37 P8. I presume that means that I need to calibrate but can't figure out how. Any help on this would be appreciated, hardware calibration doesn't seem to list fuel gauge!

 

[dynonsupport]

"CFG" means the pin is not configured, not that a calibration is needed. "CAL?" would appear for that.

That message means that nothing is configured for Pin 8 on the 37 pin connector. Likely you accidentally deleted the config, not changed it. Go in there and make sure you still have a sensor on pin 8 that is a pressure sensor called FUEL.

 

[Derek_Liston]

Sorry if I appear thick, maybe it is old age, but could you possibly give me a step by step to do that?

 

[Dynon]

The best comprehensive resource is the SkyView Installation Guide, but basically, assuming you have fuel pressure on pin 8, and that you're using the newer Kavlico 3 wire 15 PSI sensor (p/n 101690-000):

-Press buttons 7/8 to enter setup
-Go to SETUP MENU > EMS SETUP > SENSOR INPUT MAPPING
-On the C37 P8 line, select PRESSURE in the first column
-Then, nudge over to the middle column, select the correct p/n (likely 101690-000)
-Then, nudge over the the right column, and select FUEL. Then press SAVE.
-Go to SCREEN LAYOUT EDITOR. Verify that the widget is now fixed and isn't showing the c37 p8 marking.

 

[Derek_Liston]

Thanks, I was just checking, did all that, my fuel pressure transducer is a small brass item with a totally different Pt No which I meant to note last time I was out at the airfield but was sidetracked by assisting someone with a Jabiru undercarriage problem and forgot! If it is Ok with you I will continue this Thurs/Fri once I've noted the number. I am suspecting I may have been supplied the wrong part.

 

[Dynon]

Could be. Note all the numbers on the sensor when you look at it next (they won't be the Dynon part numbers, even if it's the ones we sell)

 

[Derek_Liston]

Went out to the airstrip today to do weight and balance and noted fuel pressure transducer Pt Nos. Top line reads L1911, lower line reads P4055-15G (without a magnifying glass that is what it looks like but might be 19G)

 

[Dynon]

So that's the 15 PSI Kavlico sensor and should work if you've selected the one described as such in the sensor input mapping page (101690-000). If you're still seeing the issue, get a settings backup from your display (we're interested in both the .dfg and the .sfg), along with a picture of EMS page, and email them all to support at dynonavionics dot com. We'll see if we can see what's going on with your configuration.

 

[Derek_Liston]

On checking I discovered that fuel pressure was shown on P9. I changed it to P8 and am now getting a reading again albeit still too high. If it is Ok with you I'll get back to you shortly, first I want to try changing the ground/earth wire. Currently I have it grounded to th firewall which should work since my ground block for all of the black Dynon wires is also on the firewall though on the other side of the plane.

 

[Derek_Liston]

With the assistance of Jake Jansen here in Australia, problem solved. Turns out grounding to the firewall was not such a good idea. Changed the ground to one of the skyview black wires and problem resolved. Very impressed with the level of assistance from Dynon also though, thanks for your help, until next time!

 

[Imback_Again]

Mine is also reading higher than my steam gauge did. I have it set to the 101690-000 but it's still high. The number on the sensor is J1214 P4055-5025-1. Does that tell you anything. The package said it was the 101690.

 

[Dynon]

That marking is a little odd. If it was the 15psi sensor (the 101690-000), it should be marked p4055-15g (similar to as its depicted on our recent technical advisory, which you can see here). You might email a picture of the markings to our support team at support at dynonavionics dot com so that we can help you figure out what sensor it actually is.

 

[dynonsupport]

Edit: That is one of the 15PSI sensors. There was a slight change recently and that's the new manufacturer part number. This has the same output as the old one so it has the same Dynon PN.

How high is it reading?