Engine Monitor upgrade VM1000 -> G3X: Experience?

[Dan 57]

Hi all
About to start on the replacement of my dying (LCD screen) VM1000 engine monitor with a G3X (GDU470).

I've drawn the Garmin interconnects to my GNX375 and the 2 G5s, but wonder about the GEA24 EIS to the individual probes, wiring and compatibility.

Would appreciate feedback from anyone out there having done the VM1000 to G3X upgrade, thanks.

 

[rickrv8]

Dan,

I made the exact change a couple years ago. Of all the sensors, only the original fuel capacitance sensors and fuel flow transducer were the ones I was able to reuse. I had to replace the oil temp, oil pressure, manifold pressure, CHT, EGT and ammeter sensors. RPM comes from my electronic ignition which worked with the G3X. All that being said, I’m very happy with the results.

 

[mburch]

There is a guide to sensor compatibility in section 21.2.6 of the current installation manual (revision AU), which you should find helpful.

I have been involved in quite a few retrofit installations of this type. I would say that it's typical to replace the oil temperature sensor, and possibly pressure sensors - especially if they are of the old VDO "can" type. Fuel flow and fuel quantity sensors can usually be reused. Any Type J or K CHT or EGT thermocouple sensor will be compatible, so these should not need to be replaced. And, any reasonable ammeter shunt will probably work, as long as you know its mV/A specification.

 

[rickrv8]

Matt,

I wish it were that simple but that was not my experience. My VM1000 was an early model and many of the sensors they used were simply not compatible. I worked with Stein and Garmin on the retrofit and had to replace a number of sensors and I did try to reuse as much as possible.

 

[mburch]

I wish it were that simple but that was not my experience. My VM1000 was an early model and many of the sensors they used were simply not compatible. I worked with Stein and Garmin on the retrofit and had to replace a number of sensors and I did try to reuse as much as possible.

I'm curious what specific sensors you had... thermocouples especially are very generic and can easily be reused.

 

[rickrv8]

It was a couple of years ago and the sensors that weren’t compatible found their way to the trash. I originally installed the unit twenty some years ago. But I know for a fact that the CHT and EGT sensors did not work, because I did try. Same for the oil temp sensor. I also wanted to reuse the amp sensor. However, the Vision sensor was a Hall Effect style unit that was either a three or four wire unit. I spoke to the G3expert folks who verified it wasn’t compatible. I ended up using their simple shunt. And I can’t recall exactly the details why, but I do remember replacing the manifold and fuel pressure sensors after discussing with Stein.

As I mentioned, the FlowScan (fuel flow) sensor is compatible. It just requires a simple calibration. The Vision capacitance fuel level sensors also worked fine. I worked with EI to verify their compatibility. And like fuel flow, I had to recalibrate. I was particularly glad those sensors worked given the difficulty of replacement had that been necessary. RPM and voltage were also easy to hook up.

I really did want to retain as many sensors as possible not so much due to the cost but for difficulty of installation. It was extra work but in retrospect, not nearly as big of a chore as I had anticipated. Today, everything works great.

 

[Dan 57]

Thanks Rick & Matt, great infos

Luckily I had anticipated that not all the sensors would work, so also ordered the 4cyl sensor kit. But I want to replace as few sensors as possible since I have a new TB engine on order, and wanted the new sensors on the new engine. OTOH no clue about how and when that engine will turn up...

So basically the way to do it is

• check compatibility according to the table, exchange sensor if necessary
• hook up and try sensor if unsure

Just hope, my CHT/EGT and fuel sensors (using an E.I. gage right now) will work...

 

[Southern Pete]

I'm about to embark on the same journey because several sensors are unreliable, and other reasons, so I am going to replace all of the sensors. The worm drive clamps holding the EGT sensors are breaking, the FP sender works only occasionally, the MP sender is unreliable and the tach signal from the P-mags is not compatible. Luckily I don't have fuel quantity in the VM. I don't really want to continue with 25 year old hardware when it is not expensive to fit replacements. I am also taking the opportunity to replace the fuel hoses, improve and shorten the routing and to better mount the pressure senders. The G3X system is expensive so no point in continuing with potentially unreliable parts for a few additional $$ and hours.

 

[g3xpert]

Sensor Compatibility

Thanks Rick & Matt, great infos

Luckily I had anticipated that not all the sensors would work, so also ordered the 4cyl sensor kit. But I want to replace as few sensors as possible since I have a new TB engine on order, and wanted the new sensors on the new engine. OTOH no clue about how and when that engine will turn up...

So basically the way to do it is

• check compatibility according to the table, exchange sensor if necessary
• hook up and try sensor if unsure

Just hope, my CHT/EGT and fuel sensors (using an E.I. gage right now) will work...

Hey Dan,

You will find Rev. AU of the Installation Manual at this link. Page 21-1 is where the sensor compatibility table begins. You can cross reference the sensors that you currently have installed, with the information in this table to identify which ones will work and which will not. You can always call or email us along the way, for help in this process. Our email address is [email protected], and phone number is 1-866-854-8433.

Thanks,

Justin

 

[Dan 57]

All copied Justin, that compatibility list looks good, and willco.
Thanks to your gang for the already performed troubleshooting of my schematics

 

[IO390]

I recently installed EGT and CHT probes from another manufacturer and am putting a G3X in now, but a K type thermocouple should all work the same so you shouldn't need to replace these.

For the pressure sensors I've bought UMA items specified in the G3X install manual as they are cheaper than the Garmin ones, and the temperature sensors I will get Garmin ones to avoid calibration problems.

 

[Dan 57]

Ok guys, some feedback on my progress... sure is a good thing I'm retired since the upgrade is taking, as expected, quite longer than scheduled

I have yet to run the engine, but can report on the following:

Matt is correct...

I would say that it's typical to replace the oil temperature sensor, and possibly pressure sensors

Though the EGT and CHT seem to work (I just had to replace the pins, work the grounds, etc, etc), the old P & T sensors are not working. The most surprising was the oil T sensor, a 2 wire thing which did not work... Replaced with the one provided in the kit.

Regarding the fuel quantity, my VM1000 did not have them, but a E.I. dual gage (FL-2CA) was used, as the sensors are the Van's capacitance plates.
It now seems to work, but I still have to perform the calibration procedure. More details in this thread: https://vansairforce.net/community/showthread.php?t=165654
Again, thanks to Matt for his guidance, and yes, I now used the "Fuel Quantity (Digital)" configuration.

Keeping the dual G5 set-up, linked to that GNX375, and having that GDU470 mainly for engine monitoring duties, complicates matters somewhat. I'm having to change all my previous configurations, and luckily do get some very good guidance for the g3xpert (thanks to Savannah & Katie for their patience), so all bugs should be ironed out soon

 

[Dan 57]

And since I don't want to crowd VAF with yet another G3X thread...
I'm not sure if the VM hall ammeter will work (see pic below), and don't know which way to connect it to the GEA24.

The unit itself is a CSLA2GE, which normally only has 3 wires, +, -, and o. Now the VM has 4 wires, black, white, green, red... how come?

 

[Dan 57]

I was able to run the engine a few days ago, also calibrated the fuel gages. All sensors, but for that ammeter mentioned above, working good.

The install is now complete, and not really a surprise, took twice as long as anticipated.
Skipping Stein and doing one's own wiring, removing the E.I fuel gages, rewiring some of the stuff, configuring and programming, all of it very satisfying, but somewhat time consuming.

The finished product below...

 

[Dan 57]

A few final notes re this upgrade, now that all works

The nice sensor compatibility list from Garmin is basically useless if one doesn't know which sensors are installed, which was my case. Identifying those is not always easy...

Eventually I had to replaced the oil pressure, oil temperature, fuel pressure, MP, and ammeter (hall, now Ampac KEY100) sensors.

The configuration and programming is quite time consuming, using an external power supply a requirement.

On my first take-off all CHTs shot thru the 500°F limit, and sure enough I later found out that the VM CHT probes are of J type, whilst the EGT are of K type.
My old Floscan 264 works, but obviously indicates way too high, and will be replaced at the next opportunity with a standard red cube, part of the sensor kit.

The fuel calibration takes some time to perform, the more so if smaller increments are used (I used 5L), which improves accuracy. On a taildragger to be done in flight attitude first, and later in ground attitude.
Better be sure to have an uninterrupted access to the pump

 

[Dad's RV-10]

Don't agree. I had the dual G5 already installed, and the costs of the G3X as engine monitor upgrade were as follows, all in US$:

• 175.75 GEA24 connector kit
• 115.00 GA26X GPS antenna
• 73.75 GDU470 install kit
• 1083.00 Lycoming 4 cal probe kit
• 3345.00 GDU470 7" portrait display
• 795.00 GEA24 engine interface unit

Totals $5569.50

I didn't want to to derail the other thread but I'm curious what other functionality your GDU-470 provides in this fairly uncommon configuration?

Does it receive ADAHRS information from the G5 over the CAN bus, allowing it to provide attitude info? What about the myriad of other pages normally available on an MFD (map, chart, weather, etc)?

 

[Dan 57]

Does it receive ADAHRS information from the G5 over the CAN bus, allowing it to provide attitude info?

Yes it does, if wanted. But since the attitude info is derived from one or the other G5, and the GDU470 not in front of me, I disabled the input.
Typically all the other MFD functions are available (but for WX and Cht), see the screenshot examples below. All in all very happy with the upgrade.