KOSO fuel sender
- Thread starter PeteB
- Start date
It happened to me -- I caused it though.
I inadvertently changed the KOSO setting in the fuel setup program. Try the 100 ohm setting not the 510. It just toggles back and forth so it's easier to leave it on the wrong setting. -- Give it a whirl.
Swapped Send and Neg wires would make a high-end reading, though I'm not sure it would get all the way to F on the E100/F0 ohm range.
I inadvertently changed the KOSO setting in the fuel setup program. Try the 100 ohm setting not the 510. It just toggles back and forth so it's easier to leave it on the wrong setting. -- Give it a whirl.
Swapped Send and Neg wires would make a high-end reading, though I'm not sure it would get all the way to F on the E100/F0 ohm range.
My fuel sender went to reading FULL permanently after 7 months of faultless operation. I contacted Joel of Centroid the manufacturers. He was very helpful with prompt reply Emails.
I had my sender wired to operate only with Ignition ON. I isolate the battery when the car is not in use. The SEND signal is connected to the KOSO. I learned from Joel that the KOSO SEND port has a 5Volt pull-up and so when the KOSO is booted that signal appears at the sender. The sender is calibrated by jumping the NEGATIVE and SEND contacts and will set the fuel level it sees at that time. It seems that this is what happened at KOSO boot up, but not all the time (it's microelectronics so can be a timing or a set of cirumstances thing, believe me). I now feed the SEND signal through a relay that it powered by the POSITIVE signal to the sender so isolating the SEND at KOSO boot up. The following are the notes from my problem fixing file.
Tank level sender:
10 displayed bars = 0 ohm
9 displayed bars = 10 ohm
8 displayed bars = 22 ohm
2 displayed bars = 68 ohm
1 displayed bars = 82 ohm
2 bars = 5 gall
5 bars = 10 gall
Add 5 gall to 5 bars = 8 bars
Calibrate level Sender: (No connection to KOSO during this)
Set EMPTY: Sender out of tank, connect NEG, jumper NEG and SEND, put voltmeter on NEG and SEND. Connect POS and after 10 seconds remove jumper. Volts should toggle between high (4.7v) and low (11.2mV) to indicate it calibrated.
Set FULL: same procedure as for Empty but with sender in fuel to FULL position. In a measuring cylinder works well.
Sender consumes 14mA when powered.
During KOSO boot SEND is at 5.02V then ramps down to 3.7mV at boot end.
Relay with diode isolated coil for SEND line to isolate during KOSO boot and avoid possible calibrate.
I had my sender wired to operate only with Ignition ON. I isolate the battery when the car is not in use. The SEND signal is connected to the KOSO. I learned from Joel that the KOSO SEND port has a 5Volt pull-up and so when the KOSO is booted that signal appears at the sender. The sender is calibrated by jumping the NEGATIVE and SEND contacts and will set the fuel level it sees at that time. It seems that this is what happened at KOSO boot up, but not all the time (it's microelectronics so can be a timing or a set of cirumstances thing, believe me). I now feed the SEND signal through a relay that it powered by the POSITIVE signal to the sender so isolating the SEND at KOSO boot up. The following are the notes from my problem fixing file.
Tank level sender:
10 displayed bars = 0 ohm
9 displayed bars = 10 ohm
8 displayed bars = 22 ohm
2 displayed bars = 68 ohm
1 displayed bars = 82 ohm
2 bars = 5 gall
5 bars = 10 gall
Add 5 gall to 5 bars = 8 bars
Calibrate level Sender: (No connection to KOSO during this)
Set EMPTY: Sender out of tank, connect NEG, jumper NEG and SEND, put voltmeter on NEG and SEND. Connect POS and after 10 seconds remove jumper. Volts should toggle between high (4.7v) and low (11.2mV) to indicate it calibrated.
Set FULL: same procedure as for Empty but with sender in fuel to FULL position. In a measuring cylinder works well.
Sender consumes 14mA when powered.
During KOSO boot SEND is at 5.02V then ramps down to 3.7mV at boot end.
Relay with diode isolated coil for SEND line to isolate during KOSO boot and avoid possible calibrate.
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PeteB
GT40s Supporter
Mike, just checked and it's set to 100 ohms, so unfortunately that's not the problem.
Jerry, thanks for the info. I disconnect the battery when I park it, so that's probably my issue. I think I'll have to live with it for the rest of the driving season because I have to take the seats out to get the the sender. I'll be adding an access panel to my list of winter projects.
Jerry, thanks for the info. I disconnect the battery when I park it, so that's probably my issue. I think I'll have to live with it for the rest of the driving season because I have to take the seats out to get the the sender. I'll be adding an access panel to my list of winter projects.
:thumbsup: That is very useful info, Jerry.
PeteB, your sender is probably set at FULL when the tank is part full. If you can easily get to the SEND line from the sender, at the KOSO or elsewhere, why not fill the tank then do a calibrate as I described using a local Ground. Then put the SEND through a relay, which does not have to be right next to the sender like mine. Your EMPTY setting should still be valid. It should work for you.
Link 2 wire: http://www.centroidproducts.com/2wire.htm
Link 3 wire: http://www.centroidproducts.com/3wire.htm
A piece of leftover metal trash/debris, if bridging the centroid inner spaced "tubes", will also effect it's operation - the inner tubes must not touch each other.
Just something else that comes to mind....
Link 3 wire: http://www.centroidproducts.com/3wire.htm
A piece of leftover metal trash/debris, if bridging the centroid inner spaced "tubes", will also effect it's operation - the inner tubes must not touch each other.
Just something else that comes to mind....
Last edited:
PeteB
GT40s Supporter
Yes Pete if it is calibrating when the KOSO is powered up as I describe it will set FULL at that fuel level. Can you get access to the SEND wire easily ?
Yes I guess it probably would be. I think they call that a bummer.
PeteB
GT40s Supporter
Very annoying. The sender randomly shows totally full, then will go back to working, also quite randomly. I almost ran out of gas at the track because I had no idea how much fuel I had as the gauge was reading full. When it finally decided to work it read completely empty. When I got to the gas station I put 16 gallons in. Not sure what the SLC fuel tank capacity is, but I had to be running on fumes.
The tank holds 19.2 gallons, according to my calculations. The sender will likely read empty before the tank is literally empty as it sits above the bottom of the tank, so there's a little "reserve" built into the sender architecture.
You also probably have a swirl pot or surge tank that adds a bit more.
You also probably have a swirl pot or surge tank that adds a bit more.
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