fuel gauge stopped reading right

SIV Allan

SIV Allan

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Filled up the Tiger this morning - to the brim.

Many miles later the fuel gauge still indicated 11 ++ gallons.

A 100 miles later it dropped to 8+ or so - very inaccurate.

I drove over a dirt "washboard" road to see if anything might be stuck and could be shaken loose, to no avail.

How can I trouble shoot this - or is the problem almost certainly with the sender?

A check for loose wires at the fuel gauge and in the trunk at the sender found none, and exhausted my electrical skills :eek:

As I'm a few thousand miles from home, in Bozeman Mt, looks like I'll be using a pen and notepad to estimate when to fill up...unless a fix appears.

Thanks in advance,

Allan Ballard
 
Wiper arm

No quick fix,
D.D. has just been working thru same problem in a related thread.

Remove the sending unit and clean all connections. Check float for leaks .
A few tabs hold down the cover over the guts. Exposing the wire wound and wipers assembly. Inspect for light contact with wiper arm and wound wire unit.
The contacts should be clean.

That's all I can add for now.

Cobrakidz has been looking on line for a spare.sender and has had no luck.
Let me know how it works out.
 
To be honest. I use milage, not the fuel guage on trips. Mine reads high and then suddenly drops.

When I fill up at the station I look at my GPS and 150 miles later, looking for fuel again.

Around town, just throw in a few gallons when the guage shows 1/4 tank or less.
 
Unlikely to be a leaking float as that give you an empty/lower reading.

The spring on the floats can sometimes bind causing it to give inconsistent readings... earthing and connection scan also be an issue.. regulator for gauges... none are easy fix on the road.
 
Gauge

The gas gauge on my first Tiger was always very erratic. The yardstick I kept in my trunk (to stick down the filler hole and measure fuel level) was always accurate. Drove my first Tiger cross country extensively, second what Duke said "fill up, 150 miles and start looking for a gas station". I also bought a high quality 1 gallon steel gas can with a positive seal cap and carried it full in the trunk, because I hate to walk.
Bob Knight
B9471705
B9471929
 
fuel guage

allan,
do what tiger tom used to do when he checked the spare tank in the tow tiger. get a cheap yard stick and stick the tank. duke's idea works also
 
I zero the trip odometer at every fillup. At 150 miles of street driving I fill up.
On a highway trip I can go 180 miles.
My gauge works and is as accurate as any old gauge of this type but the odo method works for me.
 
Bob Knight said:
I also bought a high quality 1 gallon steel gas can with a positive seal cap and carried it full in the trunk, because I hate to walk.
Click to expand...

Good catch, I also carry a full gas can. It is a BMW can designed to fit inside the spare tire. Unfortunately, it will not fit in my 13" spare.

img0272a.jpg
 
If the float had a hole in it, it would fill with fuel and sink to the bottom showing you an empty tank all of the time.
If the wiring connections were dirty/loose/corroded it would show low or empty or go up and down all of the time.
It could be one of four things... the points in the gauge regulator are sticking, the heating element in the gauge regulator has an intermittent/corroded internal connection, the gas tank sending unit float arm is sticking, or the gas tank sending unit rheostat wiper arm is either sticking or loose on the shaft.
The regulator can be checked with a 12v test light connected to the gauge output and a good ground. With about 1/2 tank of gas, when you first turn the ignition on, the test light should come on steady and then it should begin to flash on-and-off after a short interval. If it does this, the regulator is probably good and you should remove the fuel tank sending unit to find your problem.
When I started having problems with my fuel gauge, I bought a cheap wooden yardstick, drained my fuel tanks, and added gas in 2 gallon increments while marking the yardstick as I added gas. I eventually fixed the fuel gauge problem (the sending unit) but the yardstick is still in my truck for potential future use.
 
Come on fellas

I have had pin hole leaks on floats, and as due diligence say check as long as its out.

Great yard stick idea,

Duke what model is the BMW can out of? CT Honda's have a great but side mounted 3/4 gallon size spare tank.

Alan you deserve a gold star or two by your name as one of the bravest Tiger tamers. You were at T.U. in Big Bear and I was amazed what you had crammed into the car for spares. I suspect a yardstick is the only thing you have space for:)

The whimpy sender gasket and ring are available at S.S. but not much else. Has anyone seen a good replacement sending unit?
 
FWIW, there are both a 9L (as linked) and a 6L version

the 6L will fit under some 14" wheels, where the 9L is 15" and larger.

I'm looking into some sources. Figured we might have more than a few buyers for these. And, in early 2004, they were <$90. So, $260 seems steep.

MBZ has similar models and I'll be looking for others too.

Thanks to Duke for sharing.
 
wag123 said:
If the float had a hole in it, it would fill with fuel and sink to the bottom showing you an empty tank all of the time.
If the wiring connections were dirty/loose/corroded it would show low or empty or go up and down all of the time.
It could be one of four things... the points in the gauge regulator are sticking, the heating element in the gauge regulator has an intermittent/corroded internal connection, the gas tank sending unit float arm is sticking, or the gas tank sending unit rheostat wiper arm is either sticking or loose on the shaft.
The regulator can be checked with a 12v test light connected to the gauge output and a good ground. With about 1/2 tank of gas, when you first turn the ignition on, the test light should come on steady and then it should begin to flash on-and-off after a short interval. If it does this, the regulator is probably good and you should remove the fuel tank sending unit to find your problem.
When I started having problems with my fuel gauge, I bought a cheap wooden yardstick, drained my fuel tanks, and added gas in 2 gallon increments while marking the yardstick as I added gas. I eventually fixed the fuel gauge problem (the sending unit) but the yardstick is still in my truck for potential future use.
Click to expand...

I grounded a test light and hooked it to the gauge output, with the gauge wire disconnected and then again with the gauge wire connected.

In each case, with the ignition switch off, the test light came on solid.

It did not flash on and off.

With the ignition switch on, the test light did not come on.

Meanwhile, the fuel gauge now drops to about 1/2 full, then goes back up again, so one end of the system or the other has changed behavior from yesterday.

I'll experiment with an aftermarket gauge.

Thanks again for the feedback from everyone.

Allan Ballard
 
Moondoggie said:
Paul....I thought that looked pretty good also so I went looking around the web for one. Found one on Ebay http://www.ebay.com/itm/BMW-9-Liter...r_Truck_Parts_Accessories&hash=item3ce4449ef4

Buy it now for $260 !!! from Poland no less........

Moondoggie
Click to expand...

MD:
Hmmm. Perhaps there's a somewhat more "affordable" option out there. I've been fortunate so far to never have run out of fuel in over 20 years of Tigering. But the notion of carrying some extra just in case, appeals to me.

Thanks for the link. Maybe it's a good deal? :)
Paul
 
other portable fuel cell options

like Duke's the best so far, but newer designs and safety first for offroaders...

http://rotopax.com/home.php

Number of mountable systems, could get one for fuel and one for overheating coolant concoctions. Or... beverage of choice.

sorry, was mesmorized by interesting parts thingy. Back to sender / sensor issue...
 
SIV Allan said:
I grounded a test light and hooked it to the gauge output, with the gauge wire disconnected and then again with the gauge wire connected.

In each case, with the ignition switch off, the test light came on solid.

It did not flash on and off.

With the ignition switch on, the test light did not come on.

Meanwhile, the fuel gauge now drops to about 1/2 full, then goes back up again, so one end of the system or the other has changed behavior from yesterday.

I'll experiment with an aftermarket gauge.

Thanks again for the feedback from everyone.

Allan Ballard
Click to expand...
You would hook the test light to the gauge REGULATOR output and a good ground.
If the test light is coming on when the ignition switch is in the off position, you are either hooked up to the wrong place or you have another more serious electrical system wiring problem. This is more than likely what is causing your fuel gauge malfunction. I suspect that you might be getting 12v going directly to the fuel gauge and bypassing the gauge regulator. Your jostling the wires around under there may be why it is behaving differently from yesterday.
Forget trying to adapt an aftermarket fuel gauge. None of the aftermarket fuel gauges are compatible.
 
DD (CA) said:
the 6L will fit under some 14" wheels, where the 9L is 15" and larger.

I'm looking into some sources. Figured we might have more than a few buyers for these. And, in early 2004, they were <$90. So, $260 seems steep.

MBZ has similar models and I'll be looking for others too.

Thanks to Duke for sharing.
Click to expand...


Here is the MBZ model....http://www.ebay.com/itm/Mercedes-Re...Parts_Accessories&hash=item337fa04ff6&vxp=mtr

Not much cheaper but interesting as I've never seen either before and have owned BMW & MBZ for years. I guess they were not legal here in the states.

Moondoggie
 
BMW can, got it when stationed in Germany. Even then, they were getting expensive as BMW stopped making them. They were available for all BMW's in the 1980's. I sold quite a few of them to guys in the states when I was in Germany.

Ask me about the over $10,000 in euro E28 headlight sets I sold too. Got them for $30 in the junk yards and sold for $290 all day long. This was also before ebay hit Germany and ruined the market.
 
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