D10 EMS RPM and Fuel Pressure problem

[Bud_Keil]

I purchased a flying RV-7 built in 2005 with 500 hrs TTSN and a D10 EMS. Today, when I started the engine after a short flight, my EMS started acting up. My MAP and TACH graphics swapped positions (usually the Tach is far left, now the MAP is), the tach is reading only 1/2 speed, the fuel pressure is reading 1/2 the normal pressure, my carb temp bar disappeared as did my LOP percent bar. All other readings appear normal. Any ideas? :-?

Bud

 

[Dynon]

That sounds like for some reason, the settings on your EMS were lost. They're stored in non-volotile flash memory, so that shouldn't happen, but, if there were an anomoly that caused that memory to become corrupt, factory defaults may have been restored. Each of those symptoms you've described relate to a particular setting (option to swap map/tach, pulses/rev for the tach, and the "wrong" fuel pressure sensor setting for your engine, respectively). The installation guide should be your first step (available from http://docs.dynonavionics.com) - literally go through the entire setup chapter. Our technical support can help you with some of the questions you'll probably have too. Based on what you've said so far, you'll need to at least: flip the tach position via SETUP > SENSORS > TACH, change the fuel pressure sensor needs to be set to either type 1 (older VDO style sensor) or 6 (kavlico) depending on which physical sensor is connected (assuming that your engine is carbureted). Your pulses/rev setting needs to be set to halved, and the other things are a little more complex but are covered in the manual.

 

[Bud_Keil]

Thanks for the feedback. I am running a older version of firmware (5.2) when 5.5 is available, so I will be updating that. My tach and Hobbs also reset to 0 so I will have to reset that (fortunately, I have paper back-up). I bought the plane from a second owner who also does not have a soft back-up file. I will be backing up my settings when I get things sorted out.

 

[Bud_Keil]

I have changed the config settings for the above issues and that fixed those issues. Then my Carb and OAT temp settings went away. I changed GP inputs and fixed those as well. Now the only thing that is still a little wacky is that my %Power is not functioning, my True Airspeed on my EFIS is not working. Is there something else that I should be looking at?

My plan is to get everything working properly again, backing up the settings, then upgrade the firmware.

 

[Dynon]

That means that neither your EFIS nor EMS are seeing OAT. The carb temp is on some (any of the 3)GP inputs, and needs to be re-configured as such. Going back to the OAT - do you know where it is physically connected? The reconfiguration instructions are different for EFIS (via the magnetomer) vs the EMS (via a GP input)

 

[Bud_Keil]

The OAT probe is physically located beneath the left wing, near the Aileron bellcrank. Where the OAT is electrically connected, however, I don't know. I will look at both the EFIS and EMS installation and owners manuals and play around with that.

 

[Dynon]

So - IF it's hooked up at the EDC, make sure that EFIS>SETUP>OAT is set to type 2, and that none of the GP inputs under EMS>SETUP>SENSORS is set to OAT.

If it's hooked up to the EMS, it's the reverse: make sure that the GP input that the OAT is connected to is set to OAT under EMS>SETUP>SENSORS , and make sure that EFIS>SETUP>OAT is set to N.

Then, after you've gotten the correct configuration, from your EFIS, perform a DSAB configuration.

 

[Bud_Keil]

Ah, I think that I may see what I did wrong. I checked my hardcopy of the EFIS installation and there are many hand written annotations indicating that the OAT was connected to the EFIS. When I reset my EMS GP settings, I indeed added the OAT to that. So, if a go into my EMS and set it to 'N', my OAT (and True Airspeed/%Power) should be restored. I'll try that this weekend. Thanks.

 

[Jiscold]

EMS-D10 Global Parameters Setup

I am owner off na EMS-D10. In Installation Guide manual page 5-3 (EMS Configuration), on item Global Parameters Setup, what is Set Hobbs Time?

 

[Dynon]

It lets you pre-set the hobbs time (total engine running time) recorded for the engine. This is useful if you install an engine in your aircraft that has more than 0 hours on it already.

 

[Bud_Keil]

It lets you pre-set the hobbs time (total engine running time) recorded for the engine. This is useful if you install an engine in your aircraft that has more than 0 hours on it already.

Or, in my case, resetting the D10 Hobbs to your actual Hobbs time when the D10 gets an attitude. :

 

[Bud_Keil]

I finally got an opportunity to work on my D10 EMS this weekend. Everything seems to be working fine now. I had to reset my total fuel tank capacity (it reset to 0), had to turn on my fuel gage display (it reset to off), reset my EMS GP setting for the OAT to "N" (my EFIS reads my OAT), and did a DSAB config.

Life is good, except for a amp meter reading and a variable fuel pressure reading. Flying around, my amp meter is showing I am charging 20+ amps (11+ amps at idle) and my fuel pressure (carb engine) reads anywhere from 2.5 to 6 psi (it does not change between engine and boost pump). Any possibility that this is all related to my initial problems? I haven't ruled out that I may external voltage regulator may be causing a problem.

 

[dynonsupport]

That amps reading sounds reasonable in a lot of cases. You may actually be charging a battery, but you may also have an install where the amps shunt is not reading battery current, but panel current. Do you actually know where the shunt is electrically installed in the system?

It seems unlikely that the fuel pressure issue has to do with any lost settings. There's no user adjustable filtering, so if the value is changing, there's no setting to adjust that. You could have the wrong sensor selected, but that would make it read 30 to 70 PSI as it varied instead of 2.5 to 6, but it would still vary.

One thing you can do with the fuel pressure sensor is to go to the sender and "replace" the sender electrically with a 47 ohm resistor. This should read 6 PSI all the time. This will tell you if you have a wiring issue, or a sender issue.

 

[Bud_Keil]

I don't know for sure how the ammeter shunt is wired, however, I think that it's in Position A (flow into and out of the battery). When I switch the field off, it shows that I am pulling -3 amps for the radios, GPS, and other things that are on. When I switch on landing lights, nav lights,... I am pulling around -7 amps. So it seems to be measuring both into and out of the battery.

I like that 47 ohm resistor check for the fuel pressure sender. Nice diagnostic check to have in my back pocket.

 

[Bud_Keil]

I found the cause of my high charging current. I have a defective, internally regulated, alternator. The high current issue seems to be concurrent with the start my EMS issues. Could they be related? I haven't checked out the fuel pressure sender check. The plane's down for it's Service Condition inspection.

 

[Dynon]

Possibly. Best course of action is to get your charging system taken care of first, and then see if any issues remain.