Converting from a VM-1000 to EDM-900 Engine Monitoring System (EMS)

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RMarkSampson
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Converting from a VM-1000 to EDM-900 Engine Monitoring System (EMS)

Post by RMarkSampson »

Been meaning to put fingers to keyboard on this topic for some time now. Thought it would be good to discuss a recent upgrade to my panel when I removed the VM-1000 Engine Monitoring System and mounted JPInstrument's EDM-900. A few DA-20s and many DA-40s were built with the VM-1000 as its primary engine monitoring system. My DA-20 had the VM-1000. I decided to do this last year when my fuel pressure sender became inoperative. There were a few other troubling issues popping up with my VM-1000 so I felt it was just a matter of time before it went totally NMC. Vision Microsystems that built the VM-1000 is no longer in business - JPI did "buy them out" which means they do some very limited customer support for the VM-1000. Bottom line, it was going to cost a minimum of $1000 to get the VM-1000 fuel pressure problem fixed with a very sketch future for any new problems that possibly would arise. The VM-1000 is basically a 20 year old computer and monitor. I'm not sure how many of us have 20-year old computers still in operation in our homes - so I decided to take the plunge and upgrade the entire EMS system. It had a few challenges but I am very happy with my decision and the result.
Old VM-1000
Old VM-1000
I selected JPI's EDM-900 because of its compact size. JPI also sells a EDM-930 that is about the same size as the VM-1000 so it would have fit into the existing VM-1000 area with only a small amount of modifications. However, I wanted to get the EMS on the left side of the instrument panel closer to the pilot's line of site. More importantly, I wanted to free up that space on the right side to mount my iPad. The EDM-900 fits into a standard 3 1/8" instrument hole but it has a rectangular face that is slightly offset. Thus I needed only a bit of room above the hole to install - which I had (the VM-1000 had a repeater which I also removed, along with the fuel gauge). So the EDM-900 was the solution I went with. Importantly, the EDM-830 is NOT what you want. It is a "secondary" EMS, thus it cannot be used by itself. If you want to remove all your current engine gauges (in my case the VM-1000) you must go with either the EDM-900 or EDM-930 as they are a "primary" EMS.

Installation required me to cut a new 3 1/8" instrument hole - taking my "7-pack" to an "8-pack" instrument panel. I actually moved my CDI to the new hole I cut and mounted the EDM-900 in the top hole where the CDI use to be. Aircraft Spruce has a 3 1/8" hole cutter that worked great - the important thing to do is to build a jig to ensure the big hole lines up with all the mounting screw holes (plus one hole where the OBS knob stick out slightly. Make sure your jig is perfect and then clamp it to the instrument panel and start drilling. Drill all the small holes first, then cut the big hole. It was then a simple matter to move my CDI to the new hole - no rewiring of the CDI required.
New EDM-900
New EDM-900
There are certainly a lot of wires to deal with - because there are a lot of sensors. Some of the sensors I did not actually replace - the fuel flow and EGT sensors were essentially the same and working fine - so now I have "spares" sitting in my hangar. However, all of the wiring was replaced - JPI does a really nice job of providing the wiring harness partly set up and ready to pull. Just take it one wire at a time and spend the extra time to figure out the best way to route the wires and secure them along the way. When it was time to turn on the power, I was very surprised and pleased to see all the sensors come to life.

I did have one issue that took a while to solve. It was the fuel level sender. My VM-1000 had a "capacitance type" fuel sender. It was very accurate so I was not really happy that when they told me that the EDM-900 was not currently compatible with my fuel sender. No matter, I bought the a "resistance fuel sender" from Diamond - which I could easily mount in my fuel tank by simply removing a plate that was installed in its place (it was standard in the DA-20 so the tank was already plumbed for it). The capacitance sender was mounted at a different location. However I immediately started having "outages" of the fuel level readings - it would either show a red X - or show zero fuel readings when there was plenty of fuel in the tank. I did a lot of troubleshooting with JPI but in the end, the EDM-900 simply did not like Diamond's resistance fuel sender. I ended up purchasing Diamond's analog gauge which worked perfectly fine (although not exactly accurate as all resistance fuel gauges tend to be). However, JPI had just developed the ability for their EDM-900 to use a capacitance fuel sender - so off to the factory my unit went to get the upgrade (at no charge). It took some beta testing to get it working (it required a signal booster that JPI supplied also at no charge) - and now I have two totally independent fuel level sensors to confirm fuel onboard. The JPI fuel level is very accurate as confirmed by a calibrated dip stick I have for my DA-20. With the right K-Factor in the system I also can compute to with a 1/2 gallon how much fuel is onboard. The Diamond analog gauge is located behind my iPad and I consider that a backup gauge to JPI's EMS. It is not nearly as accurate than the capacitance/EDM-900 fuel level system.

Most of the work to change out my EMS was done by myself and my A&P - an IA is needed to file the 337 with the FAA but that is straightforward. I did take my aircraft to an Avionics shop to hook up the EDM-900 to one of my Garmin 430's. The EDM-900 can log data every six seconds or so - to include GPS coordinates if hooked up. Also my GNS-430 can collect the fuel flow and fuel remaining information off the EDM-900 and push that information to the fuel planning page. Attached are pictures of the old and new panel - and a close up on the EDM-900. It was a sunny day flying when I took the pictures of the EDM-900 so the picture does has some glare - but actually the EDM-900 is very easy to read in all light conditions. It is certainly much better than my old VM-1000 with regard to readability. My iPad now sits on the right side of my instrument panel showing Foreflight including ADS-B weather and traffic (I also have a GDL-84 with Flight Stream ADS-B solution installed). I mounted a TSO'ed USB charger in the old fuel gauge location so my iPad now stays fully charged during flights (it has dual USB ports so my phone also is charged).
EDM-900 closeup
EDM-900 closeup
I still have my old VM-1000 sitting in my hangar - there probably is a market for someone who does not want to make the upgrade...
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pietromarx
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Re: Converting from a VM-1000 to EDM-900 Engine Monitoring System (EMS)

Post by pietromarx »

This is a really great piece. Thank you for writing it. How long did it take (without the factory back and forth) and roughly how much was the investment?

Peter
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Lance Murray
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Re: Converting from a VM-1000 to EDM-900 Engine Monitoring System (EMS)

Post by Lance Murray »

Thanks for you post. I can see myself doing this upgrade to my 2002 DA40 in the next couple of years. How do you like the smaller display? Are you still happy that you went with the 900 vs the 930?
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Re: Converting from a VM-1000 to EDM-900 Engine Monitoring System (EMS)

Post by Steve »

This is something all of us "Legacy" DA40 owners may have to consider. I'm happy with the VM-1000 as it is in my aircraft, but as mentioned, support and repair is problematic. I watch eBay for spares, and have a few components, but I'm sure that when mine eventually fails, it will be a part that I don't have and won't be able to get.

There is a lot of wiring to that sucker, and I don't relish having to wire a new box, no matter how great it works. (I'm already dreading the ADS-B exercise in a few years).

Steve
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Lance Murray
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Re: Converting from a VM-1000 to EDM-900 Engine Monitoring System (EMS)

Post by Lance Murray »

I will likely do the ADS-B GDL-88 along with the engine monitor at the same time. I doubt that will save any money but it is one less maintenance cycle.
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Re: Converting from a VM-1000 to EDM-900 Engine Monitoring System (EMS)

Post by Thomas »

Lance, I will be in the same situation soon, the VM1000 shows some signs of age, MP is off some times and so is one EGT. I did change the internal battery, its Ok now but I don`t think that was the real problem.
Anyway we in Europe are not urged soon to go for ADS B, but it would make sense do to it within the same GND time.
And my ADI make strange noise with cold ambient temp, probably a sign of a developing failure.
Have you checked the possibility of replacing it with the newly certified GARMIN G5? Is it a big thing?
Thomas Bienz DA40-180 40.337 D-ENMA (sold 08/2022)
Home Airport LSZC Buochs Switzerland
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Re: Converting from a VM-1000 to EDM-900 Engine Monitoring System (EMS)

Post by Antoine »

After having installed an EDM930 in my aircraft here a word of caution:
- Quality control of the cables is not good. Make sure you have every cable checked for possible shorts hidden inside the thermoretractable shields before installing. Mine had a short in there - straight from the factory.
- The device is incredibly vulnerable to external shorts: a short in ONE cable to ONE sensor brought down the whole interface module which included half of my PRIMARY gauges.
I am amazed that such a huge design weakness passed FAA certification. The FAA did require them to add an additional display of RPM and MP but both displays are driven by the same module which includes a number of other probes and fails if one of these is shorted.

I think they need to redesign the device to properly shield from external shorts.
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Re: Converting from a VM-1000 to EDM-900 Engine Monitoring System (EMS)

Post by RMarkSampson »

To reply to your questions, still happy. The EDM-900 has lots of versatility and I am still discovering a few hidden programming tips to customize the warnings and other display features. It is a very nice system. Having said that I would not like the EDM-900 if it were installed where the old VM-1000 was installed - the small font size would require a lot of forward-right leaning to see the actual values. But right in front of my line of sight the font size is not a problem. So if you can't mount the EDM-900 high and tight in your panel, then I would go with the larger EDM-930.

I bought my EDM-900 through Aircraft Spruce so look at their prices for the unit - I did get their $500 rebate incentive so their marketing skills worked on me. The time to install was "one week" for my A&P and myself - but probably only about three days of actual work. I also turn the time into an early annual refresh so the job list was a bit more extensive than simply removing the VM-1000 and installing the EDM-900. I did have several other sets of helpful hands show up and contribute. It did turn into an impromptu social event. Anyway, I can't exactly equate my "cost to install" A&P to actual $$'s but I would 'guess-timate" double the price of the unit if you had a shop install.

Not included in that week of work was cutting the new hole in the instrument panel - I did that several weeks in advance without needing to "down the aircraft." I used small pieces of aluminum painted black to cover the hole in the panel and kept flying. Once it was time to pull the VM-1000 that the "down time" clock starting ticking.

I had no problems experienced by Antoine - the wiring was spot on. I cannot speak to the internal modules of JPI's EDM design. Maybe because I was converting from the VM1000, I did not need any new firewall penetrations. I bought a bunch of extra shrink wrap and heat shield for the wiring - fairly inexpensive on Aircraft Spruce. The ground wire is suppose to ground to the engine block but that will take a single wire too close to the exhaust and damaging heat (in my opinion). I grounded my EDM-900 to the starter block which is bolted directly to the engine block. It kept that little wire well-away from the worst of the heat sources of the mighty IO-240B.

On the down side, some of their documentation was below par, confusing or down-right wrong. JPI's customer service was helpful to sort out questions I had. However, the customer service reps tend to press you to find wiring mistakes and/or send you software updates before they start looking at a problem with their unit. For my fuel level sender issue - I needed to graduate from their customer service to one of their engineers (that was also a pilot). I spent a lot of time looking for a "ground loop" and/or other airplane problems before they started looking at their unit. Once again the EDM-900 never liked Diamond's Resistance Fuel Level sensor - but it now loves my old capacitance sensor that the VM-1000 used. Meanwhile, the analog Diamond gauge work great the newly installed Diamond resistance fuel level sender. Now I have two totally independent fuel gauges telling me how much is left in the tank. Overly redundant (especially considering the fuel flow monitoring also installed) - but that is not a bad thing...
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