Hi all,

I'm working on my 850 and i noticed that i appear to have a pretty bad voltage drop, at the battery it reads 12.5v, at the coil it reads 10.5v, i found this out while testing the fuel sender in the boot, its reading 9.5v.

I've gone around and cleaned up misc contacts but it hasn't made any difference.

I do have a dodgy ground cable at the battery that i need to replace, but at the engine side where it comes in (not sure what its connected to) it reads 12.2v which is okish?

Is there something common that could be causing this?

thanks

Is this while the car is running or at stop?

There are choke points for current which will cause a voltage drop if the contacts are dirty or damaged. The two I would look at for an ignition run is the fuse box, and the ignition switch. Both are a little fragile with age and can cause some drop.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

This is just when its stopped, i found out when i was doing the electric fuel pump.

Thanks mick, i'll check it out tomorrow. I didn't even think to check the fuse box!

Mick is back! In the country for long this time?

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Depends if they grant him Australian citizenship

I hope you're not expecting to find 12v at the fuel sender. It runs off 10v.

Don't early 850's run 12v ?

Not according to Convertible Mini's treatise in Fuel senders for Dummies on this forum.

I thought early 850s coopers had no stabiliser so they had 12 volts and for example the fuel gauge went straight up straight up to the level not slowly up to it

i didn't realize there was 10v in minis, is there anyway to confirm it should be 10 or 12v?

You should have a voltage stabiliser/regulator affixed to a strap at the rear of the speedo. It's a small tin box with a fibre lid and a number of 14" terminals poking out (or have wires connected to them. That box turns 12v input into 10v output for the instruments (like (and in particular the fuel gauge and fuel sender). Search for the thread Fuels Senders for Dummies and in particular the postings by Convertible Mini.

850's or Coopers didn't come fitted with a voltage regulator (for the fuel gauge etc) until 1964 in the UK. I can't see it being any earlier here.. My 1964 850 doesn't have one

Fuel gauge info
http://www.somerfordmini.co.uk/eshop/in ... page&id=83
Fuel sender info
http://www.somerfordmini.co.uk/eshop/in ... age&id=161

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Wombat's part utilises later technology to good effect, but in case you are after originality there are still NOS of the stabiliser.

http://minikingdomonline.com.au/product ... condition/

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ex-NSW Police 1970 MK II Cooper S
VMCI #43

I wanted originality so I have modified both of my devices by inserting an IC into the casing and sealing it all up again. The only tell-tale is an earth screw into the side of the casing. Best of both worlds.

The judges at your next concours event will pick that up for sure. There goes 10 points for lack of originality.

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ex-NSW Police 1970 MK II Cooper S
VMCI #43