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Possible fix for older fuel gauges.

102K views 114 replies 67 participants last post by  michael morgan 
#1 ·
Gas float fix

Well, this is as good a place as any to post this. Here's the problem IMO:

The gas gauge (pre-07 at least) is a long resistor strip with a float. The float has two contacts - one on each side - that run along the resistor strip, thus changing the resitance reading which is interpreted as your fuel level. In the past, peopl have tried to fix erratic reading by taking Scotch-brite to the resistor strip, with the theory being that the strip was getting 'gummed up'. This helped at times - but sometimes not, and not for long. We were barking up the wrong tree.

If you pop the bottom off the float (it is glued or plastic-welded) you will find that the two contacts are separate pieces - one for each side. Now this is the important part: THE TWO PIECES ONLY LAY ON TOP OF EACH OTHER UNDER THE FOLAT BOTTOM (see pic with my hand in it) In other words, the circuit depends on thos two piece of metal laying on top of each other (!!!!!) There is NO connector or screw to secure the plates and ensure they stay in contact (double !!!!!!!!!!).



When I took my float apart, I found that the two contact plates (brushes) were discolored from time and fuel exposure - including where they overlapped and were supposed to be closing the circuit. I cleaned them up and placed a TINY drop of solder to hold them to each other. (Disclaimer - I have NO idea if solder in your gas is a BAD idea, but the amount was tiny and then I slathered the whole thing in epoxy to glue the float back togther.

So far, so good! But what a terrible design...

 

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#68 ·
More older fuel sensor repair info.

Before I changed out my stock 3.5 gallon tank for the UE tank my gas gauge had worked flawlessly for 2 plus years. After the install the gauge worked intermittently? Removed the entire fuel pump/ sender assembly and cleaned it twice and the problem got worse till it stopped working all together. The third time I removed it I wasn't getting resistance across the two connectors at the top of the sender strip. Further "magnified" inspection showed that the connector tab that is soldered to the strip even though it looked connected it wasn't. Got out my soldering iron and re did the bad connection. Gauge works perfectly again!! Be very careful to not heat the connection for too long as you might melt the black plastic insulator and then your screwed.
 

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#69 ·
:banghead:Yeah, well.... My fuel gauge is rock steady - - always wrong! It shows empty after having used only 2.4 gallons (pessimistic by nearly 40%?). I make 100 miles, on average, and feel totally safe going another 30 miles while still having 'wiggle room' to find another gas station to my liking. Never hit bottom, or even close! Laugh when I cycle my trip meter and see H-Ds estimated "176 mile range" after fill-up. Really?! Not in my lifetime! Though I'd love to see my VRSCA make 45mpg but have come to recognize that it could if only in Jewish overdrive, downhill and with a strong tailwind!:moped:
 
#70 ·
The reason Harley made a reset odometer is because they knew the fuel gage would not work. I reset the odometer and have never run out of gas. If I watched the gas gauge I would still be pushing my VRod home. The only reason Harley put a gas gauge on the VRod is so that people who were going from autos to bikes would feel secure knowing how much gas they had to get home with. They knew that long term Harley riders would not be fooled by the funning looking gauge.
 
#72 ·
#74 ·
Isn't there someone on here who made one of those out of a coffee can? I just use a common screwdriver and small hammer and tap on one side, then the other, etc until it starts to move. Then just finish it by hand. Don't hit it too hard though, it will break the plastic tabs off.
 
#76 ·
low fuel bad idea

Great fix for a piss poor fuel guage. I just replaced my fuel pump, filter, ECM, etc., etc. Bad fuel is zero tolerance for VRod. When fuel guage gets into yellow, go top off tank. The gas cools the fuel pump!! It will overheat and fry the ecm. Also whatever fuel management comp you have too. Word of caution. The ecm and pump aint cheap! Now she runs like the wicked beast in heat!! Keep it FULL of the best gas, and DONT use as treatments orther than a touch of raceing fuel now and then, or we bit of octane boost. This works!
 
#77 ·
fuel pump cooling

The fuel cools the pump by passing through the inside! There is minimal cooling added from the fuel surrounding the outside of the pump. If you have a blocked fuel filter this makes the pump work harder
and will over heat it. No amount of fuel in the tank will prevent this from happening. These pumps are designed to run in or out of fuel.
 
#78 ·
My fuel gage was a little "wonky" when I first got this bike, but just as a preventive measure, I added about 4 ounces of Schaeffer's "Neutra" fuel system cleaner to make sure the injectors and whatnot were spotless. After a few tanks of fuel with Neutra added, my fuel gage seems to be working quite well. *shrugs shoulders*
I know some GM vehicles' gages will start working correctly with some Techron concentrate added to the fuel for a couple tankfuls. Maybe that's all it needed. The science behind the Techron fix was that ethanol blends tend to strip any tarry substances off the tank walls, etc. and they land on the sending unit. The Techron dissolves these deposits. If I'm not mistaken, there's even a GM TSB on the subject.
 
#80 ·
Cycle the run switch..

Whenever I start or turn on my bike and get empty or the wrong reading, I have found a quick fix.

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First of all, I always have my bike on "run" (turn it on and off with the key, and you won't ever get a dead battery from the headlight staying on during a lunch....as I found out on my first group ride....go figure..), so when I turn my bike on with the key, It's already in the run position. -This has nothing to do with the fix, it's just an FYI-

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When you turn the bike Ignition On, and have the switch on the Run position, and the gas guage shows empty or low, and you know it's not...
Click the run/off switch to off..wait 2 seconds... switch it to run... and magically it slowly raises to your current level. This won't take more than 5 seconds for a full tank. VOIALLA, you're done! This has worked every time for my bike atleast.
I personally use the trip meter, but it is still nice to see the gas guage running as a backup. }:)

Let me know if this works for you too, as like I said... it has worked every time for me, and takes only a few extra seconds before you start the bike.

If you have the problem of your tank not EVER reading any gas, this prob won't help.... but if it's the 50% of the time the gas guage is wrong, this should fix it (for a while atleast).
 
#81 ·
non alcohol gas

The vast majority of the available non alcohol gas in this area is 89 octane. I thought these bikes required 91. I would like to get the non alcohol but have been concerned with the octane. Does anyone have any recommendations or ideas. This is in response to the issue of good fuel causing fewer problems for the fuel sending unit.
 
#85 ·
If you're asking about the late Steppenwolf's fix, I did it too. My fuel gauge has been rock solid - wrong - since my repair. So I'd say the suggested fix is real, and I probably didn't do it quite right - either leaving too much resistance or not enough...
I've learned to recognize the low fuel light and empty gauge at 60 miles (half tank) ever since the fix - but at least it works...
 
#86 ·
gas gauge

Yes, I did use Steppenwolf's post to repair my sender unit. But 4 years later, on my first ride of the year, it went from 3/4 full to empty in about 2 minutes. I took the sender unit out again and cleaned the metal bar that the float slides up and down lightly with a SOS pad to remove a black build up of whatever. Problem solved. Sea foam didnt help me this winter.
 
#89 ·
As for the original post from Steppenwolf (RIP) I had to change my fuel filter and figured what the heck, I'll try the possible fix. I had tried several times before just cleaning the sender strip per the TSB. Every time it would work for about 3-4 tanks of fuel and then would go back to the inaccurate readings again.

After performing the "Fix" which I did a month and a half ago and 1500 miles. I am happy to report so far so good. The gauge is stable and works better than it ever has, even after I cleaned the strip previously. I will keep a eye on it and give updates.
 
#91 ·
I installed the Steppenwolf fix about 5 years and 100,000 miles ago and have not had a failure since.
 
#96 ·
I am sure he is on an extended road trip somewhere.
 
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