Temp and fuel gauges reading high

[garyv8]

Hi all,
I've had a look around and can't seem to find the specific fault I have.
Basically my temp and fuel gauges read higher with the engine running than with just ignition switched on.
I'm guessing,hoping,that the true reading is with ignition on and engine off,and that is has something to do with the voltage stabiliser,but would appreciate it if someone could confirm,or has had similar problems,
Van is an 84 DG w/c
Cheers
Gary

[MidLifeCrisis]

I would suspect that a 10v Voltage Regulator might have trouble making 10V from battery voltage (especially if your battery voltage is a bit low or your grounds are a bit rubbish);
So chances are that with the engine off the gauges are seeing a voltage lower than 10v then with engine running they see a good 10v (as your alternator will be putting out 14v-ish)

Must admit that I've never even tried seeing if gauges read different with engine not running vs running - is it a big difference?

[Oldiebut goodie]

Of course some numpty could have put the voltage regulator in upside down so it isn't working at all! Especially as the cheap replacements are the LM10 type which have reversed input and output pins.

[garyv8]

Well,it was enough of a difference to make me think she was running way too hot,although there were no other signs of overheating,reading just under max,but with engine off,ignition on,drops to just over halfway and fuel gauge drops about quarter of a tank when I kill the engine

[MidLifeCrisis]

Can you measure the 10v out of the voltage regulator - it certainly sounds like something is a bit weird there?

[Oldiebut goodie]

And a picture of it in position!

[Smiffo]

This is an odd fault. The symptom is different with the engine running as opposed to being off.

I am interested to see how this goes.
Would it be possible for the blue ribbon to be corroded, and allowing current to leak across from other circuits?
Something changes with the engine running, so it could be the 12v coming from alternator when it's running leaking across?

I am randomly guessing here - not making suggestions I think it would likely be - but if you are getting behind the dash to check the voltage regulator, it is easy to check the condition of the blue ribbon too.

[Oldiebut goodie]

If the regulator is either fubarred or in the wrong way it is possible that alternator off it is passing just 12.7 ish volts but is putting the full alternator voltage of circa 14v through the gauges with engine running. Hence the rise in readings.
I can't be bothered at the moment to dig out an LM10 and check though.

[garyv8]

We have news,
Pulled dash apart and checked stabiliser,sure enough with the engine running its banging out about 11.8v ,but with engine off about 9.8v,weird thing is,for about ten mins it played ball with engine running too and gauges stabilised,(sorry!),but then it started messing about again and gauges started going north,bit of a huge relief and mild frustration as spent last few weeks trying to work out why the motor was running hot,much wailing and gnashing of teeth!!!
Incidentally,is there an accurate wiring diagram for an 84 DG around as the Haynes one is about as much use as a chocolate teapot,regarding the colour coding and pin connection,I might just as well use a psychic,
Cheers

[CovKid]

Most of the main loom uses exactly the same colour coding as bays and most 70s bugs

[garyv8]

Any idea where i can getbone of these stabilisers,preferably a good one,I've been all over JK,brickworks etc,can't see them anywhere

[Oldiebut goodie]

99p for 5
http://www.ebay.co.uk/itm/5pcs-L7810CV- ... SwfY9XP~O5

NOTE these must be mounted 'upside down' as the pins are reversed. Pack out the space between the tab and the circuit with metal as the heatsink will not be effective otherwise.

If you want to buy a pukka one like the original it will cost you around 60 euros - that was the price when I last looked.

[boatbuilder]

Buy a few spares...it's easy to wire them up backwards which kills them instantly.

Sent from my GT-I9195 using Tapatalk

[Oldiebut goodie]

More than 5?