15 replies to this topic

[edmawbs]

Hi,

I have just fitted dual fuel tanks to my MPI & have nearly done 250 miles on a single fill up. However now the tanks are getting low I am getting some strange gauge readings.

When I start it will read about half and 10mins later or when I travel at speed the gauge will drop to nearly empty. I have checked the right hand tank and more fuel moves over when it's been running.

Now I am not sure but I thought maybe it was the pressure of the left tank pushing it through, so I put a vented cap on the left tank to let pressure escape. But this hasn't made a difference. Just for information the tanks are connected by a balance pipe, with no secondary pump in use.

Any help or suggestions would be greatly appreciated - I should have around half a tank left of fuel in total across the 2 tanks.

Thanks everyone in advance! 😀

[splintercat]

you don't really say what your set up is        in terms of how the two tanks are linked if they are linked or exactly what fuel gauge set up you have? Do you have individual fuel gauges or just one ? and how on earth is the fuel gauge/gauges wired in to their respective senders?  need a bit more information mate.

if your operating twin MPI tanks then surely the fact that they have their own in built fuel pump so can't you operate them as a separate operation something like a changeover switch into a common line and then just put in separate fuel gsuges.

[edmawbs]

Sorry, wasn't to accurate on info!

So I am using an MPI 7.5 gallon tank on the left as standard with the standard pump inside the tank. Then a 5.5 gallon s tank on the right. They are plumbed together by a balance pipe at the bottom on each tank.. The MPI I drilled and fitted an adapter for the pipe to fix onto.

I don't have an original MPI dash, this has been converted to a 3 clock dash same as the Austin/Morris setup.

The only outlet on the right tank goes to the left where the fuel is pumped the usual way. So no extra pump or gauge.

Thanks - hope this is accurate enough :)

[CityEPete]

Is the right tank vented?

[Steve220]

My thought would be to vent the right tank into the left via a breather pipe.

[edmawbs]

The right tank is vented through the boot floor via a thin pipe.

[Steve220]

Where does it join the tanks though?

[edmawbs]

It joins at the bottom of each tank

[mk1leg]

Is the right hand tank connected to the sucking pipe from the pump inside the MPi tank as they are supposed to draw at the same time here is a pic of a standard twin connection......

[pdaykin]

Is the RH tank plumbed in to the fuel return pipe rather than the feed ?

With respect to venting, the twin tank setup had a crisis cross arrangement to stop them draining down - IIRC it was a factory modification in the 60s due to problems. The LH tank vent pipe runs under the parcel shelf and vents through a hole in the boot floor near the RH tank. The RH tank does the opposite.

[edmawbs]

No it's not connected to the pump - just the pipe connecting to the left hand tank. I bought the kit from wood and Pickett, they said just the 1 pipe and breather pipe through the boot floor would be OK.

So maybe this is my problem. If so how do I fix it? And just out of interest what range do you get out of your MPI with the twin tanks?

[ChopperHarris]

Nothing wrong with your installation.
The gauge is probably misreading due to a faulty voltage stabiliser?

[mk1leg]

No it's not connected to the pump - just the pipe connecting to the left hand tank. I bought the kit from wood and Pickett, they said just the 1 pipe and breather pipe through the boot floor would be OK.

So maybe this is my problem. If so how do I fix it? And just out of interest what range do you get out of your MPI with the twin tanks?

so your still drawing from the 7 gallon tank and the rh tank is gravity feeding the 7 gallon tank.....yes or no....put some pics up installation

Edited by mk1leg, 14 March 2016 - 08:49 PM.

[ChopperHarris]

No it's not connected to the pump - just the pipe connecting to the left hand tank. I bought the kit from wood and Pickett, they said just the 1 pipe and breather pipe through the boot floor would be OK.

So maybe this is my problem. If so how do I fix it? And just out of interest what range do you get out of your MPI with the twin tanks?

so your still drawing from the 7 gallon tank and the rh tank is gravity feeding the 7 gallon tank.....yes or no....put some pics up installation

That's how I read it

[edmawbs]

Sorry for the delayed reply, yes the RH tank is gravity fed and the LH MPI tank is still drawing the fuel.