I

IHMS

New Member
Hi Everyone,
I have a fuel gauge that only goes up half way. I put in a new sending unit in the tank. To test it, I grounded it out so the fuel gauge itself went promptly up to full. Cleaned the grounds, cleaned all the contacts at the dash and tank...and with a full tank, it only goes up to "half full" maybe a tad higher. What-in-the-name-of-sam-hill is going on here?!?! She is a 2.25 Petrol 2A with the tank under my seat.
 
Hi,
Lucky you. depending on which day of the week it is my gauge is all over the place.
I have tried the same but still no different.
If you solve the problem please let me know how you did it.
Cheers
 
Check to make sure that the voltage stabiliser is ok on the back of the speedo.
On one side of the fuel guage you should get a fairly close 10volts with a multi meter, or you could just try changing the stabiliser if you have one knocking about, otherwise there might be something up with the sender, theres a sliding contact that rubs up and down a coiled resistance wire track, there might be a couple of turns worn through, failing that its possible that the tanks been changed at somepoint and the sender does not match the guage, smiths do weird things and do not allways stick to a standard.
 
Thanks guys...that is my next move. That voltage regulator box thing may be the trick...because it regulates my temperature gauge and thats looking a bit anemic also!!! The next time I am tempted to tell someone to "get a life" I will just tell them to get a Rover and after a while they will wish they had their life back!
 
Hmmm, the old Voltage stabilizer problem... Last summer I had a problem with mine... Fuel guage would read full until about 50 miles from empty...:eek: The temp guage would read that the engine was near overheating, when it was actually just fine. I replaced the voltage stabilizer and it lasted about 6 months, and erratic problems all over again... The replacements don't seem to last long.

I found a thread that mentioned an integrated circuit voltage stabilizer for a replacement. So I tried it. you need a IC 7810 available at any electronic components store for about 1 quid, a couple of connectors. It will work on 12 or 24 volt systems and output consistent 10 volts for the guages. The hardest part of the task was soldering wires to the 3 legs (voltage input, ground, 10v output).

Here is a link to how to do it. Mine works great!
How To: Replace Your MGB Thermal Voltage Stabilizer:D
 
Thanks RJ!
I will look for one on Saturday! I wonder if those part numbers are universal?? I other words, if I give somone in China Town that number will they know what it means?:)

Again,
Thanks a ton,
Mark
 
Yep 7810's are standard, less common though 7805's and 7812's are the popular ones.
If you can get a 7810CV then do that, the CV means mil spec and will be very hardy.
The same trick can be done with a 7805 and a couple of components, bit more difficult though.
If you look inside a ford stabilser from the late 80's there is indeed a 7805.
If you cant get a 7810, I have a circuit for one using a 317T which is an adjustable regulator.
 
Have you tried operating the level out side of the tank? with it earthed as would be the case when installed. I once replaced my sender unit, and also noted that there was adjustment on it that you set. You set the sliding contact thing in relation to the coil. Basically get the sender set up out side of the tank, then move it till the full position, see what the reading is on the gauge, then adjust for full, and then check empty as well.
 
I will check both, but I think RJ's first suggestion is likely on the money...because of the tandem anemic response of my temp gauge which is run off the same voltage regulator. Thanks very much. Will keep you both "posted".:rolleyes:
 
Most leyland vehicles used the same stabilser, you might find a breakers with an older vehicle with one on.
 
Just a little update. My IC voltage stabilizer has seen extreme temps in the past year (-10 F - +110 F) and is still working well. No perceptible drift in the guages... Good luck. IHMS, We never heard back on yours...
 
I agree with NickWhiteKent, Great Thread ! I am suffering the same malady but only with the fuel gauge, Will be having a look for my regulator with a view to it's replacement
 
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