9A EIS 4000 Fuel Level #'s

339A · #1 09-06-2010, 11:56 AM

Looking for someone who has done the EIS 4000 tank calibration for a 9A. Getting ready to put my panel back together and was hoping to get the AuxSF and AuxOFF numbers? Would give me a starting point and something to compare to, any advice or lessons learned doing the cal would be nice also.

Thanks,

rv9av8tr · #2 09-06-2010, 05:18 PM

Not that simple. I never could calib mine that way. Ended up adding known quantities and read xmiter output, then entered that into the EFIS tank calib table. It was frustrating.. and the level indication is still erratic.

gmpaul · #3 09-06-2010, 08:40 PM

Scott--- Mike is right on this. I could never get my tank levels to calibrate in my 9. After saying this, my EIS fuel flow is dead on, also my watch still works as a backup.
G.P.

RVbySDI · #4 09-07-2010, 02:00 PM

The previous posts do not give me a "warm fuzzy"!

I am dealing with the same calibration issues with my EIS. I have started with the numbers that were given to me by Sandy at GRT. It is indeed a frustrating process. I started the process by writting down the numbers on the display when the tank was full. (Actually, it appears that although Vans states the tanks hold 18 gallons, mine are holding more like 20 gallons.) Then I emptied the tanks and wrote down the number on the display at empty.

After getting these numbers I called Sandy and gave her the numbers. She then gave me the AUXSF and AUXOFF I should set my EIS to. These were still not quite correct as they were reading incorrectly when empty. The wrong time for a fuel gauge to be inaccurate! I have adjusted them a few times already but still cannot get them to read accurately when empty.

Just a note on the numbers. Sandy informed me when she gave me the AUXSF/AUXOFF numbers to only adjust the AUXOFF numbers. She also told me to only use ODD numbers when adjusting the setting.

This fuel quantity issue is not the only fuel reading problem I am facing. I also am frustrated with calibrating the Fuel Flow on the GRT EIS/EFIS. This is done with the FloCal and, since I have a return fuel line with an additional Red Cube sensor on it, the FloCalR.

My fuel burn readings have been off by quite a bit. The instrument was reading 8.5 gal/hr during my first few flights. I have been flying several hours at a time at around 75% burning a lot of fuel while breaking in my new engine. When I return I fill up the tanks and record the gallons added. By recording the actual fuel flowing into the airplane, I am finding that my actual burn rate has been around 12 gal/hr. This 4 gal/hr difference between the instrument readout and the actual burn rate is most definitely not going to work.

One does not want to go fly, for say 3.2 hours with 36 gallons, non-stop at this rate of burn without stopping for fuel. Doing the math a person can see that 12 gal/hr X 3.2 hr = 38.4 gallons. Hmmm, good thing I had 20 gallons in those tanks instead of 18.

Relying on an instrument with this amount of error could make for a really bad day.

I am currently using trial and error and trying to measure as precisely as I can the amount of fuel I am buring on each flight to calibrate these instruments. I would welcome anyone's ideas on any better solutions. Is it just going to be a trial and error process? Or, is there a better way?

If I am going to rely on these instruments they need to be accurate!

339A · #5 09-07-2010, 02:49 PM

The calibration procedure certainly appears to be a bit of a PITA. But it can be done and has been done by others. This previous thread goes over the process and it seemed to turn out well for Bubblehead (it's a fairly long thread).

It's apparent that getting the cal done correctly is the key. I will work on this and see what kind of #'s I get.

What I was hoping for is someone who feels confident that they have done it right. The other post deals with a 8 so the #'s won't work in the 9A.

My guess here is that the resistive type floats are pretty similar across the 240 - 30 ohm range once installed in the tank, but I'll be the first to say that installation differences could really throw things off. Also the A/D conversion going on in the EIS could make a difference.

I used to have a standard fuel gauge with a switch (to select tanks), it worked great I knew where five gallons was... not enough room in the new panel for it and I wanted to eliminate some parts.

BTW, I also have the fuel flow and it took a while to get it sorted out originally. Mine is accurate to within a half gallon most of the time now. Keep at it and you should be able to see the same. I just kept adjusting the #'s till it was repeatable at fill ups. Definitely a trial and error type of calibration.

Best Regards,

Scott

Quote:

Originally Posted by RVbySDI

The previous posts do not give me a "warm fuzzy"!

I am dealing with the same calibration issues with my EIS. I have started with the numbers that were given to me by Sandy at GRT. It is indeed a frustrating process. I started the process by writting down the numbers on the display when the tank was full. (Actually, it appears that although Vans states the tanks hold 18 gallons, mine are holding more like 20 gallons.) Then I emptied the tanks and wrote down the number on the display at empty.

After getting these numbers I called Sandy and gave her the numbers. She then gave me the AUXSF and AUXOFF I should set my EIS to. These were still not quite correct as they were reading incorrectly when empty. The wrong time for a fuel gauge to be inaccurate! I have adjusted them a few times already but still cannot get them to read accurately when empty.

Just a note on the numbers. Sandy informed me when she gave me the AUXSF/AUXOFF numbers to only adjust the AUXOFF numbers. She also told me to only use ODD numbers when adjusting the setting.

This fuel quantity issue is not the only fuel reading problem I am facing. I also am frustrated with calibrating the Fuel Flow on the GRT EIS/EFIS. This is done with the FloCal and, since I have a return fuel line with an additional Red Cube sensor on it, the FloCalR.

rv9av8tr · #6 09-07-2010, 09:59 PM

Not to throw salt in a wound... but I've also found that even when "calibrated" on the ground, they don't show the same level when in the air. Basically, I've found these individual tank float level indicators to be worth about +/- 5 gal of what ever they indicate. You're best bet is to keep tabs of on-board inventory with the fuel flow transmitter totalizer.

With the GRT EIS-4000, I set OF=0 and SF=200. This resulted in doubling the scale from empty to full, essentially increasing the "distance" between each Gal of fuel, which I found to result in less variation to the Gal scale in the EFIS.

I put a couple gal of fuel in each tank, then pumped the tanks empty with the fuel boost pump, that way leaving any "unusable" fuel in the tank. Then I had the FBO gas truck fill ONE tank to the brim.... my -9A took EXACTLY 18 gal to the filler neck. These tanks are standard, so I can't remotely imagine how someone could get more in. The last 3 gal is SLOW to fill as the air works it's way out of the tank.

Then I hooked up the fuel line at the Fuel Servo inlet, to a tygon tube and ran it to the empty wing tank. Set the EIS fuel totalizer to 18 gal, then start pumping from the full tank to the empty tank. The EIS totalizer should reach "0" fuel remaining when the transfer is complete. Adjust the FloCal accordingly. By swapping the tygon tube between tanks, you can pump back and forth between the tanks until you're happy with the Cal number. I ended up with the FloCal=201. With one tank full and the other empty, you can transfer fuel and with each passing gal (one down and one up) I recorded the LT signals.

Then put those numbers directly into the GRT EFIS fuel tank calib table. It's as close as you're gonna get.
These are the values I got. But each airplane will be different:
<IMG>http://picasaweb.google.com/mikerv9a/FinalAssy#5514386075024230658</IMG>

339A · #7 09-08-2010, 02:59 PM

Boy, hope I can get better accuracy than +/- 5 gallons.

My old fuel gauge was better than that! I will go through the Cal process and see what I come up with. I'll post the #'s when I get done. I like your idea for running the tanks dry and checking the fuel flow. Seems like my FloCal # is around 180 or so. During the first fill up five years ago I know it took 18 gallons, but I want to verify that as well.

Hope to get this stuff done over the weekend as I should have everything back together. Saturday 9/11/10 will be the 5 year anniversary of 339A first flight, so I'm hoping to get back in the air on Saturday. I won't have any help as everyone from KFTG seems to be headed to the Badlands fly-in.

Thanks for the ideas.

Scott

Quote:

Originally Posted by rv9av8tr

Not to throw salt in a wound... but I've also found that even when "calibrated" on the ground, they don't show the same level when in the air. Basically, I've found these individual tank float level indicators to be worth about +/- 5 gal of what ever they indicate. You're best bet is to keep tabs of on-board inventory with the fuel flow transmitter totalizer.

With the GRT EIS-4000, I set OF=0 and SF=200. This resulted in doubling the scale from empty to full, essentially increasing the "distance" between each Gal of fuel, which I found to result in less variation to the Gal scale in the EFIS.

I put a couple gal of fuel in each tank, then pumped the tanks empty with the fuel boost pump, that way leaving any "unusable" fuel in the tank. Then I had the FBO gas truck fill ONE tank to the brim.... my -9A took EXACTLY 18 gal to the filler neck. These tanks are standard, so I can't remotely imagine how someone could get more in. The last 3 gal is SLOW to fill as the air works it's way out of the tank.

Then I hooked up the fuel line at the Fuel Servo inlet, to a tygon tube and ran it to the empty wing tank. Set the EIS fuel totalizer to 18 gal, then start pumping from the full tank to the empty tank. The EIS totalizer should reach "0" fuel remaining when the transfer is complete. Adjust the FloCal accordingly. By swapping the tygon tube between tanks, you can pump back and forth between the tanks until you're happy with the Cal number. I ended up with the FloCal=201. With one tank full and the other empty, you can transfer fuel and with each passing gal (one down and one up) I recorded the LT signals.

Then put those numbers directly into the GRT EFIS fuel tank calib table. It's as close as you're gonna get.
These are the values I got. But each airplane will be different:
<IMG>http://picasaweb.google.com/mikerv9a/FinalAssy#5514386075024230658</IMG>

DGlaeser · #8 09-08-2010, 04:27 PM

I followed the GRT instructions and my 7A fuel levels are pretty good.
One thing to remember is that the floats will reach their highest point BEFORE the tank is full. On my tanks, the floats top out at the 15 Gal point. So from 15 to 21 gal (7A remember), the EIS reports 15 gal.
I recently had to remove a tank to fix a leak. I had to cut a hole in the rear baffle and reseal a lower skin-to-baffle area, and then install a patch on the rear baffle. When I refilled the tank, I did it incrementally and checked the EIS gauge readings. They were within 1 gal at all points. That's all I expect from floats

I have the fuel injected Fuel Flow option - reads the pulse to the injectors to determine fuel flow - and it is very accurate. I would expect the carburated fuel flow sensors to give similar results.