V8S Fuel Gauge Sender
Discussion
Does anyone know where sender unit in located (no prizes for "in the fuel tank"!). I want to check the terminals/connections. My gauge has developed Parkinson’s and I want to check the circuit first. Hopefully it's not the usual inaccessible TVR lash up ie up on a ramp, remove the cradle and drop the whole tank, not forgetting of course to remove the exhaust system first! I suppose an inspection hole in the boot would be far too much to ask? Cheers. Joe
Checked the voltage from the live wire to the sender and it was 8 volts, i presume there is some kind of voltage stablisation in the line and the earth wire had a good earth. On testing across the two terminals on sender unit there was an open circuit so i think the sender has broken down. I've not ordered the parts yet, need to get me finger out and not rely on the can in the boot.
This link here explains how I did mine: see July 13th.
http://tvrgit.com/jul08.html
and this link here gives a bit more advice before you start:
http://www.tvrsseries.com/fuelsender/fuelsender.ht...
The sender is basically just a big potentiometer with a resistor on a swinging arm. Once you get it out, you can test if it's working, using an ohm-meter - although if it's anything like mine, it will be bloody obvious that the contacts have worn away to nothing.
As you say, just make sure you have the fuel level below the bottom level of the sender unit - it might also help to jack the car up on one side only, so that the fuel lies to the other end!
http://tvrgit.com/jul08.html
and this link here gives a bit more advice before you start:
http://www.tvrsseries.com/fuelsender/fuelsender.ht...
The sender is basically just a big potentiometer with a resistor on a swinging arm. Once you get it out, you can test if it's working, using an ohm-meter - although if it's anything like mine, it will be bloody obvious that the contacts have worn away to nothing.
As you say, just make sure you have the fuel level below the bottom level of the sender unit - it might also help to jack the car up on one side only, so that the fuel lies to the other end!
Fuel sender document from the factory.
As far as I aware only the bottom one is still available. TVR Car parts stock it - or did (and it went onto my 1991 V8S so you might be in luck.)
HTH
edited to remove thumbnail and insert image - doh
Edited by tubbystu on Saturday 31st July 19:08
Edited by tubbystu on Sunday 1st August 11:20
Hi
I replaced my fuel gauge sender last week. It is on the nearside of the fuel tank, about half way up. You can see it of you peer behind and around the rear wheel. I tested mine by running the wire from the gauge to earth and making sure that the gauge was working. I also checked the earth connection. On my S3 the top wire on the sender goes to the gauge. The middle one has two wires and is the earth. the bottom connection is blanked off. I drained the tank with a length of pipe and a container ( miss-spent youth?!?). The sender unit is of the later pattern shown in the diagrams so I would guess that a V8 would have the same.... But it is a TVR. I ordered a new sender, locking ring and gasket from TVR Car Parts and they arrived next day - brilliant service. The locking ring was corroded badly and I had to bend it in one place to be able to get my tin snips in to make a cut and remove it. The track was worn out, hence no reading. I then cleaned up the mating flange on the tank and it all fitted back together nicely. However the fuel gauge does not seem to be well damped. The needle rises and falls on bends. Just like an old Morris Minor. I don't know if there is a fix for this or whether it is a 'characteristic'.
Cheers
Tony
I replaced my fuel gauge sender last week. It is on the nearside of the fuel tank, about half way up. You can see it of you peer behind and around the rear wheel. I tested mine by running the wire from the gauge to earth and making sure that the gauge was working. I also checked the earth connection. On my S3 the top wire on the sender goes to the gauge. The middle one has two wires and is the earth. the bottom connection is blanked off. I drained the tank with a length of pipe and a container ( miss-spent youth?!?). The sender unit is of the later pattern shown in the diagrams so I would guess that a V8 would have the same.... But it is a TVR. I ordered a new sender, locking ring and gasket from TVR Car Parts and they arrived next day - brilliant service. The locking ring was corroded badly and I had to bend it in one place to be able to get my tin snips in to make a cut and remove it. The track was worn out, hence no reading. I then cleaned up the mating flange on the tank and it all fitted back together nicely. However the fuel gauge does not seem to be well damped. The needle rises and falls on bends. Just like an old Morris Minor. I don't know if there is a fix for this or whether it is a 'characteristic'.
Cheers
Tony
Thanks for the info chaps. Mine is the third type in the drawings above, but my earth wires (2) go in to the boot). Out of interest the voltage supply to the sender unit was 6.4v and the resistance across the sender terminal was something like 126 ohms. I’ve cleaned the terminals, replaced the live feed spade (which was unsheathed & manky) and water-proofed it all. Net result, it’s stopped flicking up and down but it still wavers about on bumpy roads so I'll regard that as a result. Thanks again. Joe
It was showing near empty as it happens. When I brimmed the tank the following day it got stuck on 3/4 full for a few miles and then pinged up to full. Then it started flicking up and down again so I'm guessing there is a bit of corrosion on the sender unit mechanism. Once the fuel level drops a bit, the flicking stops and it just "wobbles" as normal. It'll do, it’s a TVR after all!
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