2003 ST4S fuel sending unit float tube 552.1.003.2a

[mario65]

I took mine out and and checked it with an ohm meter and it seems the ohm readings are parallel with the fuel gauge readings. It is full when full and as soon as it gets just below full it is reading the same as empty.

Before I get a new one just checking if someone has one.

Part #88650011A
SEAL RING
SEAL RING $13.62

Part #42540041A
FUEL FILTER(updated, order #42540041B)
FUEL FILTER(updated, order #42540041B) $25.52

Part #55210032A
CARBURETTOR LEVEL SENSOR
CARBURETTOR LEVEL SENSOR $184.11
Continue Shopping Checkout Sub-Total: $223.25

[Stick]

Mario:
It sounds like your sender is working, if you can "see" it decriment in steps. I was in messing with mine (I forget why...maybe just curiousity), and I noticed that rather than a linear function, it seemed to step down in increments of ??? hundreds of ohms. And each step would have been = to a segment on the readout.

So if you're seeing this on an ohmmeter, I think you'd be waisting your money on a new sender.

Not sure why your gauge is going to empty, when it's just of the "full" mark. Check your elect. connectors between the tank and up to the readout.

A cheap solution is to reset your trip odometer at each fill, and make sure you get fuel at 120 or 150 miles.... It's a true 5.4 gallons if the tank is dry. I've pushed it's limit more than once!

[MarkST]

Mario, any chance of some pics please ? I'm particularly interested in knowing how to get the unit out and then put it back in again.
Good luck with sorting yours out.

[Stick]

Speaking of connections... there's the obvious one under the tank. Then the next "problem-child" is the big one that connects the rear harness to the front harness. It's over near the fuses (left side---all the bodywork must come off!!!!!!!!!!!!!!)

Sounds like 11K, you's might be an over-washed garage queen? Water gets into this big connector. Check for green corrosion, and good luck.

Another weak connector is on the readout itself. I hear that these get the green/corrosion gremlins, too. Maybe even erosion as one of the gents in here has re-soldered (tinned) the edge connector to try to save the unit.

[mario65]

She is a beauty and everything I have is a garage queen. I do ride her but with other bikes she mostly is what I ride when my wife wants to ride along.

I was trying to say that I am sure its the sensor because I would think that the sensor would show incremental changes on an ohm meter as the float changed. It really doesnt it jumps to 275 ohm just below full. That exactly how the guage reads, its full until until the gas drops a bit and then it jumps to empty.

I think if I had to do it all over again Id lift the tank and see if moving the tank causing the bowl to slide in the tube would show the same reading.

Once I did pul everything I plugged it up to the bike outside the tank and i twisted the the tube back and forth and the gusge respond exactly as the ohm meter responded. Thats why i think its the sensor. I did also tke it apart ad play with the feelers inside the float and it didnt help. The stick that the feelers slide on is the issue I believe.


Steps to removal.

1. Siphoned the gas in the tank
2. lifted the tank and siphoned more
3. Unplugged the fuel lines (tank tilted back)
4. Uncrewed the screws holding the pump on the tank.
5. Slid it out a little and unscrewed 2 more fuel lines connecting the pump to the inside of the tank. also unplugged the fuel pump from the sensor(held in the tank with rubber grommets.
6. Looked in the tank with a flash light and saw the rubber grommets holding the sensor just pop out. so I pulled a little and took it out.

Pretty easy to remove.

I saw someone had a post here where they had a short in the wire providing power to the sender all the time they fixed after a headache. I dont have power when the key is off at the pump connector.

My connections are clean.

Ill update when I get the sennsor.

[mario65]

I got my sensor today and it clearly was the sensor. As the float slides in the tube it gives a different reading. When I plugged it all up outside the tank the gauge followed the float perfectly.

Ill take pics and log the readings before I put it all back. Just waiting on a new o-ring.

[mario65]

I finished fixing it this weekend. I bought a sensor off of ebay and it was perfect. When it arrived I put the ohm meter on it and as the plunger slid the ohms changed slowly but consistently. Again my other one had a reading at full but once the level dropped it was the same reading down to empty.

I put a few pics up of the inside of the tank. This repair is easy. Get the filter from napa that is slightly narrower but similar and get a new o-ring and you dont be afraid you cant break anything.

[98_ST2_in_WV]

Does anyone have the actual ohm readings for full and empty? From other posts I've come across, not ST related, it appeas they should be 100 and 510. Is this correct???

Thank you
Pete

[Nashduc]

Did your gauge do this all at once or was it gradual? My '05 gets to about 1/3 to 1/2 tank and then claims empty! sometimes will come back and show some fuel after while... wonderin if mine is doin like yours?

[MrHeeltoe]

Oh lordy, this part has seen a massive price increase! I can't find it less than $440!