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TR6 TR6 gas gauge not reading correctly

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I

ichthos

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Hello Everyone,

I am still going through TR6 withdrawls - the one day it did stop raining in over a month, I wasn't home. It is too cold now to put the new top on. I figure I might as well make the best of it and finish up on minor repairs here and there that have been bugging me.

I could use some help on fixing my gas gauge, which is not reading correctly. I have two gas gauges, and both read the same, so I don't think it is the gauges. My next culprit would be the gas tank sending unit. When I top the car off, the gas gauge reads 3/4 full. Since my car sat for so many years with an empty tank, could it just be that the float lever is bent? Is it easy to bend it back? Would I be better off to just send it in to get repaired/recalibrated? If so, does anyone know of a company they would recommend?

Any suggestions would greatly be appreciated.
Kevin
 
Hello Kevin,

the first easy check is to short the sensor cable to a good earth with the ignition on, if this gives a full reading the voltage stabiliser and gauge are correct and it is indeed a sensor fault.
Unless a wrong sensor has been fitted it is unusual for it not to read from full to empty so check that the tank is properly earthed. If the above are all correct then you will have to remove the sensor and go from there.

Alec
 
Sounds like your float has a hole in it. I think your float is gas-logged (as in water-logged) and is dropping too low, hence reading that you need more gas to be full. The fix is buy a new sending unit or find a new float. Do a search on this forum and you will find that some of the members found a good replacement float to repair the old sending unit, as I remember.
 
Hello Bill,

surely a holed float would fill then sink to the bottom giving a permanently 'empty' reading?

Alec
 
Alec-

Actually I had exactly what Bill described, twice - one Spitfire, one TR6. Seems like some amount of air was still trapped in the float so it had intermediate buoyancy.

Randy
 
I will check to make sure the tank is grounded properly. Where is the tank grounded from/to? Since the gas gauge does work normally except for starting out at 3/4,it doesn't seem likely the ground would be a factor. I already checked the fuel gauge with two different stablilizers, and I didn't notice any difference. I guess that only leaves the sending unit at this point. Does anyone have a source for floats and/or someone that can repair the sending unit? When possible, I have found more success in repairing old parts than buying new, since I never know what quality of new parts I am getting. I wish the big three would reveal the source of where each of their parts were manufactured in their catalogs.
Kevin
 
Kevin,
The ground for the fuel tank is on the sending unit next to the green wire which goes to the gauge.
There was a thread here which mentioned that you could get a brass float from Ford to replace the plastic one. I think you can get that info from the Buckeye Triumph club web site as well.
 
On a TR4 I have used a length of solid copper wire (like 12 ga house wiring) bent into a long 'L' to test the sender. You can stick this in thru the filler hole and either press the float arm way down to simulate empty or hook it an pull it all the way up to simulate full.

If pulling it all the way up gives you a full reading on the gauge then the float is certainly suspect.
 
Ok, actually a topic I can weigh in on and be of some use. I had a sunken float for my fuel sending unit. I checked to make sure it was the float and not the unit by shining a flash light in the tank and seeing the float sitting on the bottom. To verify my guage worked correctly, I used a coat hanger I opened up and bent a small hook on the end and snagged the fuel sending unit arm and pulled it up. The guage went all the way up to full. I contemplated using something to patch the float or buying a whole sending unit. I stopped by my local british car shop, 'Motorhead' and they had used floats. The floats for the TR6 are the same float that is used on MGB's. The guys at motorhead verified this by showing me both new and used parts from both. Moss sells the floats for MGB's but not for the TR6. Still odd to me... So I bought a used float for $5 and a new cork gasket for the fuel sending unit for $2. If you do not have access to a place like this, I could easily stop and pick you up a used float and gasket. You can't beat having it done for $7. Just PM me. If you need an entire sending unit, you can get one from Moss for $50. Do a search on my user id to find my thread on the fuel sending unit, it was only a month or two ago and I am sure I had more detail listed there.

Good Luck,
 
I saved a copy of the Ford float picture from the Healey forum of this board. The Ford part is number: COAZ-9202-B It's a brass float instead of plastic.
 
Thanks for all the help, guys. I won't be able to get to until Christmas break. I'll let you know how it turns out.
Kevin
 
Hello Kevin,

I bow to others experience with holed floats, but you say "it doesn't seem likely the ground would be a factor".

Well, as the fuel gauge reads the resistance in the circuit, unless your ground is virtually zero ohms, that will be added to the float potentiometer reading and you will never read full.

Alec
 
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