ossman

I have a '99 bird and the fuel reserve sensor is busted. Replacing the entire thing costs a few bucks, so I was hoping it could be fixed. Has anyone here been able to do so?

I've determined it's the sensor by measuring it (it always indicates 2.2kOhm) and by shorting the leads to the dash to make sure the light there still works.

smurf211

It's the fuel sending unit in the tank. I think the total cost was ~$50. I have one but I haven't put it in yet. there is a remove / replace procedure in the service manual. It can be done by lifting the front of the tank (almost empty) and supporting it. // -sm

ossman

Yeah, I had determined as much. But a new unit costs ~$160 over here so I was hoping that were some way of fixing it.

Has anyone ripped one of these apart and determined how it works? My guesses would be conductivity through the gasoline or a chemical reaction that changes the resistivity of the element. Either way one could hope that it's a matter of cleaning it.

jonscott

What the...Wow, that'd be expensive, complicated, and dangerous.

It's a standard float sender (on my 97).

You could start with pulling it down and seeing if it sticks at a lower point, and you could try cleaning it, but it's prolly better/easier/more time and cost effective to just replace the fuel level sender set.

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DeathWish01

conductivity = electical current through something... i don't think you want electricity going through your gasoline LOL.... but yeah its usually a float

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bullet

Its a variable resistor changing its ohm output while the floater moves...

Have the service manual in hand ..then with an ohmmeter check the shown resistance by moving the floater top up and bottom down...if the values shown are out of manual specs then it is faulty and needs to be replaced...

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smurf211

I was thinking about this today. When I first got my bike I thought my sending unit was bad also. I found that the calibration of the meter is out of sorts. I was on empty and went to the station and to top off and it only allowed 4 gallons, meaning I had 2 gallons left (~72 miles). My fuel warning light finally came on after a long trip and I was close to home (many gas stations). I was relying on the trip meter to keep me in the ball park. So now I just time myself. I still have the FSU down stairs and will probably put it in over the winter and test the old one and post the results. Probably just needs to be cleaned. Just haven't gotten to it because it's riding season and haven't had the time. Depending on the rain I may get to it sooner. Get that thing down to almost empty and see when the light comes on. You'll have about 40 miles to go so have a station within reach.

*********
It is a variable resistor and the specs for full and low are in the book.
pg 19-17 Resistance (20C/68F) Full 4-10 ohms Empty 81-91 Ohms.

You can measure the resistance on the plug to see if it is varying proportionally to your gauge reading. Try this and see if we can save some money.

The 99 and 00 (which I have) are grouped together regularly for parts and procedures.


Just some thoughts. // sm

smurf211

Sorry, didn't read all of your post. I go by the trip meter as rule anyway. It may just require removal, clean and reinstall. How much to order one for you in Sweden? // smurf

ossman

Gasoline requires quite a bit of effort to ignite, so a few milliamps going through it in liquid form is not going to get me concerned at least.

ossman

This is a '99 so it has two sensors. The float works just fine, it's the reserve sensor that's busted. And that things is not mechanical but a small epoxy sealed capsule.

ossman

My English might be lacking here, but I read this as you asking what a new unit costs over here, which I wrote earlier was $160.

I'll probably end up a buying a new one next winter if I can't fix it, but I'd be much happier if I could spend those $160 on other toys.

Uglystick

If I remember correctly gasoline isnt actually flamable unitll its in vapour form..

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Uglystick

To be honest I dont think that my birds low fuel light works either. I usually fill up at about 300 - 320 klm's but I have had it all the way up to 383 on one tank and the light still hadnt come on and she was starving for fuel when travelling uphill.

Mine is a 99 also, so this may be a common problem.

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ossman

It might be a Honda issue as my VFR suffers from the same broken sensor. Might also be why the removed the sensor for the '02:s and went with just the floater.

Poundstretcher

My light seems unreliable seems to be on a lot of the time but brighter as the fuel goes down. I make sure I keep the tank topped up.

smurf211

That's what I get when I'm half asleep trying to respond to theses things, sorry. // smurf

smurf211

Air filter, plugs, PC III USB, Pipes:

smurf211

Ossman, I pulled my old FSU and have it in a box. I don't know how much shipping is but if you want it let me know. // smurf

ossman

Sure. I can make an attempt at cleaning and reviving it. USPS with their "show up some time between next christmas and never" service isn't that expensive ($11 according to their web site). I'll send you my details in a PM.

smurf211

Oss, it works I just don't know how accurate it is. At least it will give you some indication. I'll clean it up a little with some WD-40 and see about getting it to you. -sm

smurf211

Oss, fuel sending unit mailed Thursday. Send me $20 worth of Kronor s (SP?) in return. It wold be cool to have some Swedish currency. // smurf

ossman

Sure. I'll try to get some different bills and coins for you.

ossman

The fuel sensor arrived here today, so it was pretty speedy considering it was their cheapest option.

Unfortunately I cannot decipher your handwriting for your address so if you could send me your contact info in a PM that would be helpful.

smurf211

NP, I didn't clean it. I figured I'd leave it because it was working. I was going to spray it down with WD40 and wipe it off but decided against. I'll send you an address shortly. Hope it works out for you. I can get you a new one for ~$50 and send it over if ti continues to be a problem. I don't know if that's legal but whatever. // -sm

ossman

Was the reserve sensor working when you sent it? 'Cause it was dead when it arrived. I was expecting a dead sensor, but still.

The short summary is that I was unable to fix the sensor, and I believe it is impossible to repair a broken unit. Images of my adventure can be found here:

Ossman's photo gallery :: Laga bränslegivare 2009-06-19

I started experimenting with getting it running again. It showed ~1 kOhm at first, which is roughly the same as my (also broken) sensor. Through some testing I determined that the bike expects the sensor to dip below ~100 Ohm, so our sensors are way off.

My first theory was that the sensor internals were covered in the same kind of residue that was on the outside of the unit and that this was causing it to malfunction. So I started dipping it in all kinds of solvents (as I couldn't scrub the inside). Nothing had any real effect on the residue, except acetic acid. The acid managed to remove the crud off the device. Unfortunately it also played a number on the sensor itself, shifting it up to 3 kOhm instead of 1.

At this point I figured the thing was beyond repair anyway, so I started prying open the case to figure out what was in there. It's not really clear from the pictures, but the sensor consist of a small black block with connecting plates on either side. So it would seem that it works through some chemical reaction with whatever that black thing is made out of. That also means that getting it back to its original condition might not be possible, and if it is it will most likely require some exact chemicals to counteract the effect the gasoline and air has had on it over the years.

So in summary, I need a brand new unit to fix this and I'd really appreciate if you could send me one, smurf. Your prices are less than half of the ones over here after all.

Just give me some info on how you want me to send over the money.

ossman

Hey, smurf! Still with us?

smurf211

Oss,

That unit was working my bike when I took it out, just not all that accurate. Altitude ?? Kind of a stretch. Let me price out one from Ron Ayers and I will send you a PM. Let's get this fixed so you can move on to other things. I am cautious though. Are you sure the rest of the circuitry is functional. I wouldn't want to spend anymore only to find out there may be a problem elsewhere. Take it easy, from the looks of things you have probably checked all of this but we might want to double check everything. PM on the way. Sorry for the delay, I've either been working on the bike or riding. Lot's of free time lately. --smurf

smurf211

Parts found with Part Number: 37080-MAT-E00 Description FUEL UNIT SET Price $57.09

Verified from parts manual. // smurf

ossman

I'm sorry, but I don't quite follow. What about altitude?

I'm fairly sure the rest of the circuitry is fine, although you can never be 100% sure. The service manual states that you test the light by shorting the pins (which does light up the instrumentation), so it seems reasonable that a 1kOhm sensor is a broken one. To be sure though, could you measure your sensor when the tank is below reserve? It's the outermost pins for the reserve sensor.

It's been a lot of rain over here so I have a lot of time of just sitting around and coming up with new projects for the bike.

smurf211

I don't think it got there by boat or it would still be on the way. Let me know if you want me to order one for you. // smurf