Recalibrating fuel gauge

[IIA]

A few months ago I had a new gas tank installed. Everything attached to it was replaced too including the sender. But the gauge on the dash was not replaced. Shortly afterwards the gauge started acting up. Now when it reads "empty" I only need to put in about 6 gallons to get the needle to full. I know it's really full (after over filling the tank!) so I assume the tank must be at about 1/2 when the needle is at empty.

Any suggestions on what's going on and how to fix it? (This is a petrol, 1970, 88", IIA)

[I Leak Oil]

Is your new sender compatable with the old gauge? That's where I would start. If the two aren't speaking the same language then they just aren't going to be able to work as a team. So do you have the old sender? If so, put it in and see if the problem goes away.

[o2batsea]

Spiyda Design fuel gauge wizard:
https://www.spiyda.com/magento/index.php/vehicle-electronics/fuel-gauge-electronics.html

[SafeAirOne]

Also,, make sure you have the power wire and the ground wire on the right terminal(s) on the sender--Strange readings happen when they're swapped.

[siiirhd88]

This is very detailed fuel gauge info from a G&R board posting:

http://www.series2club.co.uk/forum/forum/index.php/topic,24221.0.html

Bob

[SafeAirOne]

This is very detailed fuel gauge info from a G&R board posting:

http://www.series2club.co.uk/forum/forum/index.php/topic,24221.0.html

Series 2 club posting, I suspect.

[siiirhd88]

Yes, but found via the G&R board.


Series 2 club posting, I suspect.

[IIA]

I finally got time to pull the fuel sender out of the tank. It's got a small amount of fuel inside the float. I assume that's not right but correct me if appropriate. Also, I noticed that it has 2 wires, like the diesel pictured in the link you posted. My LR is petrol, which the picture shows having only 1 connection. Does mean I have the wrong sender?

[siii8873]

it should work. The second terminal is for a low fuel warning light. More critical with a diesel from what I understand.
Can't remeber the letters next to the terminals but remember it was fairly obvious which was which

[Les Parker]

T = Transmitter

W = Low fuel warning


Hope this helps.

[IIA]

My IIA doesn't have a low fuel light, but there are two wires connected to the sender. I haven't tried tracing the wire connected to the W connector (and probably wouldn't understand what I found anyway). What could the "W" wire be for if not the warning light? Just a ground wire?

[o2batsea]

The wiring for the low fuel light is probably there behind the dash. W is indeed the low fuel light wire. Only diesels had the warning lamp connected. On petrol it is replaced by the choke lamp, if I am not mistaken.

[SafeAirOne]

Note that there are also some cam-lock-type senders (as opposed to senders that are attached to the tank with 6 screws) with integrated fuel pickup tubes that have 2 terminals but no low fuel warning circuit. The insulated terminal gets the wire from the gauge and the non-insulated wire gets a ground wire from the vehicle body. Not original equipment on SIIAs but tanks are pretty interchangeable.

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSfLWc5YRGvP28KoQ_y2iaol2sO3eg1A cB5ikeP0p7NMPWBDBYhZQ

[Fraserb]

My IIA doesn't have a low fuel light, but there are two wires connected to the sender. I haven't tried tracing the wire connected to the W connector (and probably wouldn't understand what I found anyway). What could the "W" wire be for if not the warning light? Just a ground wire? just sorted my fuel sender/gauge issues on my IIa.
Mine has the 6 bolt sender with two terminals.
don't recall what the letters on the terminals were but there should only be 1 wire connected to the sender (unless the 2nd is going to a low warning light) the correct terminal is the central one, the sender doesn't need a ground wire, the sender grounds thru the body of the sender which is screwed to the tank, which is bolted to the chassis, but well worth checking the grounding of the tank as what I have found is most of the electrical issues with mine have been poor grounding or worse, intermittent grounding!

the issue mine had was showing full or pretty much full, even when not much in the tank, then dropping to nothing, previous owner solved it by simply roadside topping up from a jerry can kept on hand. IMHO not ideal!!

I spent many hours over many days tracing wires and checking connections on the spaghetti fest of many previous owners various colored wire patches, then running new wires to ensure a constant feed, finally got feed up and pulled the sender out *blush* and the wire had been connected to the wrong terminal and the weird readings were coming from the low fuel light contact that was bent and must have contacting for part of the travel of the float.

Oh how I laughed.