I'm trying to get my low fuel circuit to work again. I have attempted this before and failed. It appears to be the low fuel circuit on my dip tube which is 29" long. This type with the fuel level sending terminal (Eagle wiring circuit #77) and low fuel terminal (Eagle wiring circuit #153) is no longer available from VDO.
I did some searches through the archives in the Eagle board and found that the replacement sender is VDO 224270.
https://www.jegs.com/i/VDO/918/224-270/10002/-1
This was also affirmed by Dan Lentz in a response post on the EI board back in 2009 that this sender was put in 1985 model 10's and 1986 Model 15's.
However, 224270 is a 27" tube and mine is a 29" tube, and the 224270 and all VDO senders no longer have the low fuel terminal.
What I am considering is installing a Centroid sender.
http://www.centroidproducts.com/
I can get it with a low alarm terminal and any length I want and set the low alarm at about 12% which will leave me 16 gallons when it begins to chime. My tank is 150 gals, but I've read somewhere only 135 gals is usable. 135x.12=16. Centroid has pretty good reliability reviews and they make a lot of senders.
My concern is the ohms of my gauge. I have the original Eagle gauge with the eagle emblem. I found a post from 2009 on the MAK board that Clifford said he thinks all Eagle gauges are 0-90 ohms, but he wasn't sure. Can anyone verify that these old VDO gauges are 0-90? I want to keep that gauge because they look so cool.
Thanks,
David
I am posting a followup with some more information.
I ohmed tested my sender and could not get any consistent or meaningful measure running the float up and down that thin piano wire. My sender has been modified by someone so it won't go to the bottom, but when it hits the home made stop it shows empty on the dash gauge and when I move the float to the top stop is shows 3/4 full which is what is shows when I fill my tank at a fuel stop.
Probably modified at Houston Metro. Must have run out of fuel a few times :o I feel like I can make a safe assumption my eagle gauge with the bird on it is 0-90 ohms and can order a centroid sender in that range. I took nearly all my fuel out of the tank this morning. I still have 3 inches of fuel from the bottom of the floor of the tank and 4 inches in the sump where the fuel line pickup tube is. I still cannot see through the liquid with a flashlight how far the pickup line is off the floor as it is still submerged in fuel. Assume 1 inch maybe??? which would put it at floor level and about 1" above the sump bottom.
It's 31" from tank top to floor, about 32.5"+/- from tank top to sump drain bottom. I can purchase a centroid sender at any length. I haven't called them yet to get their recommendation as to how far off the floor the sender should be. I started with 15.5" of fuel before I began removal and now have about 3" left. I have removed 56 measured gallons in that distance. 56/(15.5-3)=4.48 gallons per inch. 4.48x31 inches equals 138.88 gallons. The tank is has a wider berth up high which would calculate a higher volume per inch. The total tank capacity is 150 gals. Thus you have the extra gallons up high 150-138.88= 11.12 gals which looks like a good estimate when I look at the wider part of the tank.
This is a center mounted fuel tank between the bogies.
My fuel gauge sender was 29" long and modified to show empty at about 26". That is 5" off the floor.
5x4.48=22 gallons when it supposedly shows empty on the dash. 22 gallons is a good "empty tank" cushion. I fuel plan at 6.5 miles per gallon. That would be a decent place to put my low fuel alarm (4 to 5 inches from the floor.)
At my stick measured 15.5" start it showed 1/4 tank on the dash. 15.5x4.48=69.44 gallons not anywhere near close to 1/4 tank 150/4=37.5 gals. At 15 or so inches it should show 1/2 of tank on the gauge. It's wonky for sure.
In the meantime you can just use the outside broom handle and just dip the tank. You can even then dip frequently and file marks on the stick. One hundred .... 90, 80 and so forth. Dorky and somewhat silly but it works. I had the same kinda problem finding functioning sending units for my old old Stewart Mechanical gas tank gage. Finally did. Found it was a wiring continuity problem and not the sender at all. :)
I appreciate the challenge and satisfaction to return it to function.
But...
It still cannot/should not be trusted, and you will/should still be keeping track of your mileage since the last fill, in order to not run out of fuel.
The old men said it long ago:
"Only drivers with fuel gauges run out of fuel"
Whether that is a brand new coach, or one of our conversions, it still applies.
These things, for whatever reasons, just cannot be trusted in a bus.
Happy coaching!
Buswarrior
Digd you check the dash gauge and tank unit closely? Usually they are stamped with ohmage.
Quote from: chessie4905 on May 18, 2020, 03:45:11 PM
Digd you check the dash gauge and tank unit closely? Usually they are stamped with ohmage.
No markings on the gauge and you can see the embossed numbers on the sender from my picture
My GM gauge was stamped down on on the bottom.
VDO has 3 gauge resistance ranges. 0 to 90°, 3 to 180°, and 33 to 240°. Got a tank unit for my auxiliary tank and although listed as 0 to 90°, turned out it was 3 to 180°, even stamped on sender. Couldn't get satisfaction from vendor; they kept claiming it was 0 to 90°. I ended up buying a compatible VDO gauge to match. The sender actually made the 0 to 90° gauge backwards. Veryfied the issue after reading several forum posts on a boat fuel gauge forum catagory.