nightmoves

Question about fuel sending units on F model

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Hi Everyone.

I fly a '69 F with essentially no fancy stuff on the inside. Short version of the story is, I was on a 3.5hr leg recently and must have been running very rich as I had calculated I should have burned ~22 of 32 gallons in my right wing. My fuel gauge was indicating between 1/4 and 1/2 at landing. I landed, went to fill it up and I put 29.5 gallons in. Whoops..... (other wing had 15 gal available). I would have thought with 2 gallons available the gauge should have been pretty close to reading E.

I have been planning to buy an engine monitor as soon as the next JPI (or EI) rebates come out and install during January annual. I haven't been considering replacing the fuel sending units but my mechanic suggested that happen when we install the new engine monitor equipment.

Can someone tell me how to go about this without it costing a fortune? I know CieS sells units for about $450 each. I also understand that I have 4 of these suckers. Are there other options other than buying from this company? Can I somehow have mine refurbished? I will say when sealing my tanks last year the A&P said my units looked "original and very tired".

Sorry for the long winded question and thanks for the help.

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The senders can be serviced or reconditioned... but to limited effect.  I was going through this a couple of years ago myself. I finally just decided to bite the bullet so to speak and get in done once and for all.

JPI EDM-900
CiES senders all around

Fuel is no longer an issue as I know within about half a gallon of how much I have and where it is, at all times.

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Plus 1 for Paul's advice. 

I had the ACDelco senders reconditioned by Airparts of Lock Haven when I upgraded the panel including a JPI EDM 930 6 years ago. I could not/would not depend on the fuel level info but I did have very accurate fuel flow accumulator so it was not great but okay.

Earlier this year I expanded the fuel bladders to 32 per side and I took the occasion to go to CiES digital senders. One of the best things I've done. Precision is almost unbelievable.

If you want to stick with what you have contact George:

George McKinney - gmckinney@airpartsoflockhaven.com

http://www.airpartsoflockhaven.com/

 

 

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The  Ye-Olde system of fuel level leaves the pilot with a lot of responsibility to not run out of fuel...

1) book values for FF, combined with a clock, is one rough way of doing it... confirm that the book values apply to your plane.  At least... climb FF and cruise FF should be known(s) for your ship....

2) The back-up is confirming the fuel level with the fuel gauges.... (hard to do when not working properly)

3) The first step in modernization added a FF gauge with totalizer skills... (early 90s technology)

4) Cies is the next step towards digitalization...

5) integrating the engine monitor, FF, and GPS... is the ultimate of fuel situational awareness.  

6) The Cies devices add another level of awareness... you have a second method of knowing the fuel used. Compare the two.  If they are different... there is probably a fuel leak that is not being accounted for by the FF instrument.... :)

7) Confirm that your F really has four fuel level sensors... look for wires connected to the level sensor on the outboard side of the tank...  the C’s 52gal tank’s only have two floats, one on each side...

 

One thing the MSer can do is to see that the floats in the tank are moving smoothly through the entire arc.... it is possible that they get sticky and need to be cleaned...  when that doesn’t work, the lockhaven solution is next on the list...

After that, Adding FF in place of book numbers is really a quick step in the right direction...

Let me know if you find a way to add Cies and a JPI900 on a tight budget...  :)

@Jeev has been helpful at pricing strategies for JPI equipment.

PP thoughts only, not a mechanic...

Best regards,

-a-

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I was taught to never trust the fuel gauges in aircraft.  First thing installed in my F was a JPI FS-450.  Best investment I have put into the airplane.  I would love a full new engine monitor system with the fuel flow and levels but the FS-450 is a great first step for not much money.  It gives fuel remaining if you set it up correctly after fueling.  It will give fuel burned on the flight and hooked up to GPS it will give fuel required to next waypoint.  It give much better peace of mind than gauges.  It is nice to be 4 hours into a flight and know that I have 1.5 hours of fuel still on board (I have bladders and only 54 gallons of fuel).  It is also nice in fuel injected airplanes to be able to set the fuel flow (I fly high most of the time, so don't have to worry about leaning too much), I just pull the mixture back to 9 gph for cruise.

 

 

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In addition, if testing the movement of the floats, you should check the readings, make sure there is nice smooth continuous changes in resistance, if it jumps it will have to be reconditioned.
I had one that the AP said was good but turned out was bad because it did jump around making the calibration useless.

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Technically it only has to be accurate on "empty" but its nice to know what you have  as a "gross" check at the cardinal points on the gauge. 

1/2 may not be exactly 1/2 of what the tank holds. I empty the tank and refill with gas cans to check what I have at 1/4  1/2 and 3/4. One needs to level the airplane how ever first. Not just sitting on the wheels. Flight attitude. Repaired original floats work ( I had mine done years ago) and have for half a century in Mooneys BUT one needs to be cautious as they are not "exact" indicators. Where's that VFR min extra fuel? 

BTW, they are IIRC 1956 Cadillac fuel senders. 

Not knocking the new stuff but the old stuff still works. I know what I burn (10, 9, 8, 8, 8 per hour) and if I see a tank going down faster than I expect maybe its time to land and take a look?  I also have a EI FF system that is accurate to 1/2 gallon on every flight. Never to be relied on whole heartedly however. 

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I also have a JPI and the sensors and it is wonderful knowing with pretty good precision how many gallons and how many hours and minutes of fuel are on board.  I am not one to run fuel very low, but confidently knowing how much fuel is on board is great peace of mind.

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Being able to visually easily read the fuel QTY per TANK is very helpful (especially if 1 says and goes amber)

 

Would be nice if there was simply a fuel gauge that displayed the analogue gauges currently in AC with digital LCD numbers that look nice and pretty. (if there is one plz direct me that way)

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Remember there are four senders: two per tank. It seems they average the level sent to the gauges. I have just installed bladders and one of the recommendations was to overhaul senders and gauge bank. So I did and all the sudden it makes sense. At least the 0, 1/4, 1/2. 3/4 and full are now kind of accurate. I also have a JPI830, not fancy has Paul's but I feel way more comfortable.

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when I installed my MVP-50 I ordered new magnetic pick up senders from EI. they work great and are very accurate.

$350.00 each

Brian

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The cost to refurb appears to be about $165 each. This is likely the route I will take here in the next month or 2.

My plane almost always burns between 9-11 GPH but this was an unusual flight. I was near gross, it was hot and the clouds were in my way the whole way. Constantly climbing and descending to get around them. I had to constantly re-lean, which isn't super efficient using the single EGT gauge that came stock on the aircraft. So, with all the non-cruise maneuvers I had to make there was just no way to know how much I was burning... I just know the gauge was telling me "there's about as much as you think there should be in there".

I don't need anything that is accurate to the 10th of a gallon. I just need to know if there's 3 gallons in there or 10.

Thanks to all for the feedback!

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November 8, 1970 I did an "emergency" landing in Newberry SC when the engine quit while on a tank indicating 1/4 full. It was a rented G model out of Wilgrove NC which I had never flown before. The other side was already showing empty. Taxied to the pump and added 50.2 gallons in a 52.0 usable system. That was obviously a "never again" experience - I doubt I've ever landed with less than 15 gallons on board since.

And I really, really appreciate having a modern EDM, a precision FF transducer, and CiES fuel level sensors. The Est. REM graph is based on the FF accumulator and the FUEL QTY double graph is based on the CiES sensors. If there's a fuel remaining mismatch the EDM displays an alert/alarm.   IMG_20180310_112740240.thumb.jpg.78b74a94b192a04113bd068ba28dc70a.jpg

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I should know better.  I just installed an EDM900 in a C172 and I thought I would give the OEM transducers a try because they seemed to be working OK and I know how to calibrate.  The calibration results were very promising (nice curve) so I though everything was OK.  But the real world results suck.  I now get fuel imbalance warnings (when the fuel totalizer is more than 5G from the fuel quantity) and less than satisfactory Left / Right measurements on the way.  They may be true, but I think more likely the transducer is erratic.

I'm not going to try again, just going straight for the CiES transducers to get it right this time.  Attached is a picture of the panel, the EDM900 works well, even low down near the pilots knee (and near the engine controls).  Text is too small to go on RHS.

BTW, I have a couple of used FS450 FF and EDM700 systems that I have taken in trade.  Or contact me for the best deal on new systems, complete with CNC cut panel.

Aerodon

supercub180@gmail.com

 

 

 

 

 

 

 

 

IMG_7611.jpeg

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I now get fuel imbalance warnings (when the fuel totalizer is more than 5G from the fuel quantity) and less than satisfactory Left / Right measurements on the way.  They may be true, but I think more likely the transducer is erratic.

You can turn off the fuel errors.
Senders can appear to be working but when you closely monitor them as you rotate the arm you can see spikes in the readings. I had this problem with one of mine.
Out of 4 senders, the 2 lowest (inboard) were bad, as should be expected as they spend far more time submerged in avgas.

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2 hours ago, Aerodon said:

I should know better.  I just installed an EDM900 in a C172 and I thought I would give the OEM transducers a try because they seemed to be working OK and I know how to calibrate.  The calibration results were very promising (nice curve) so I though everything was OK.  But the real world results suck.  I now get fuel imbalance warnings (when the fuel totalizer is more than 5G from the fuel quantity) and less than satisfactory Left / Right measurements on the way.  They may be true, but I think more likely the transducer is erratic.

I'm not going to try again, just going straight for the CiES transducers to get it right this time.  Attached is a picture of the panel, the EDM900 works well, even low down near the pilots knee (and near the engine controls).  Text is too small to go on RHS.

BTW, I have a couple of used FS450 FF and EDM700 systems that I have taken in trade.  Or contact me for the best deal on new systems, complete with CNC cut panel.

Aerodon

supercub180@gmail.com

 

 

 

 

 

 

 

 

IMG_7611.jpeg

I used to be plagued with "Fuel mismatch" errors when I had the factory resistive senders. On the flight to burn down the fuel for the CiES installation, I got one that popped up when I was getting close to the 5 gallons per side level. Not very comforting to see that error. The CiES, despite some initial installation issues, have been pretty remarkable. I have never been off more than 0.5 gallons on a fill-up, this including any fuel expansion or contraction that might be going on.

 

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