Tank question : This one is for Brian

[Shaheenk]

Hey bud, please can you help me .

I have a 1984 South African Spec Chromie. I know it came with the extended tank behind the seat, but not sure about the tank under the seat.

Now since then I have fitted a UK spec cluster to my car, I am guessing the gauge would be calibrated different .

I want to take the aux tank out from behind the seat, so 3 questions


1. How would I achieve this , can I simply close up the pipes to the Aux tank.
2. Will the cluster be more accurate without this tank
3. What do I do with the sensor wires that go to the Aux tank.


Thanks
Shaheen

[Brianmoooore]

I can only guess on this one, since I've never set eyes on an E30 with an auxilary tank, but as far as I know, it only has a vent pipe at the top and a single large connection at the bottom through which it both fills and drains via the metal fuel filler pipe. To remove it you would need a fuel filler pipe from a single tank car, without the Y branch, and also remove/blank off whatever the vent pipe connects into.
Only guessing again, but I expect that the two fuel level senders are connected in series, the same as with a 62 litre tank, so if you have fitted a UK spec. cluster from a 55 litre tanked car, shorting together the two wires that go to the redundant sender should make the gauge accurate.

[Shaheenk]

Hye Brian

I did one simpler then the single pipe , I simply found a bung the same size as the rubber pipe and cut the pipe , then dual clamps on the byung and closed the feed to the aux tank. Much simpler , also the vent pipe went back to the carbon canister under the rear wheel well, I am just going to have to be a bit more careful filling up as the primary tank now does not have a vent.

On the sensor, I shorted the 2 wires but it makes the gauge read 1/2full when there was nothing in the tank, as confirmed by the reserve light staying on. Any other ideas on the sensor.

[Brianmoooore]

if you have fitted a UK spec. cluster from a 55 litre tanked car, shorting together the two wires that go to the redundant sender should make the gauge accurate.

You've fitted a cluster from a car with a 62 litre tank. You need a fuel gauge from a 55 litre tank cluster.
The gauge itself is easily swapped over, or you can swap the complete cluster.
If you do the latter, it will probably have come from a four cylinder car, so you will need to swap over your existing six cylinder tacho. coding plug, on the lower right front face of the cluster.

[Shaheenk]

ohhhhh, too much work , and where will I find a gauge out in South Africa. ...... ...... ..... pondering the take over of the world.

I guess I will just have to go by the reserve light.

[Brianmoooore]

You can still go by the gauge; it will still be accurate, just wrongly calibrated. Full will still be full, but empty will be half way - the entire scale compressed into the top half.

[Shaheenk]

Ahhhh ok, or I could just use my old gaude from my old cluster. And short the wires and see if that works.

Hopefully that should be a 55liter gauge.

[Shaheenk]

Hey Brian

Finally I can let you know .....its about giving back to the community.

So the tanks are indeed connected in series but the wires can not be bridged, when bridged the sender unit would be reading full, hence the gauge jumping to almost half.

If you remove the old tank you need to get a 35ohm resistor and conect it across the terminals. this makes the aux tank empty and the other gauge (55liter) read correct.

If anyone ever wants to remove or add a tank.

The value of the resistor when full is 2.8ohms , when empty is 35ohms.

Enjoy