Temp and Fuel gauge oddities

[Andrew S]

Working on a friends Stag at the moment putting a few things right.

Fitted a new fuel sender unit
The fuel tank is as good as full and the fuel gauge was reading as it should
The temp gauge however was reading around 3/4 if not higher
Replaced the temp sender unit with a trusty LDPart one
The engine is no way that hot so I have just fitted a brand new voltage stabilizer

My problem now is that the temp gauge is ready low, barley reading and the fuel gauge is about a third

I have put the old voltage stabilizer back on and it reverts to how it used to be, 3/4 on temp and as good as full on the fuel

I have put a wire to the fuel gauge to see if it a bad earth and made no difference

I have taken the green wire off the fuel sender unit and earthed it and the gauge slowing when off the scale

Any ideas much appreciated
Andrew

[V Mad]

Is the new fuel gauge a solid state one or the old thermal type? Measure the voltage and see if it is a steady value, in which case 10 volts is correct. If its the thermal type you can't easily measure it so it might be suspect even though it is new. You know how unreliable new parts can be.

[Andrew S]

Thanks Chris, Ill start off with the 10v supply test first.

[Andrew S]

The temp gauge reads low as I am expecting rather than the 3/4 read or more I had before.
The fuel gauge was reading low so I have removed the tank sender unit and compared the sender units side by side and can see that there is a big difference as you can see, so this explains the difference in the readings. With the old sender unit in, the gauge is reading with the engine running a needles width above half. Looking at my photo of the level of the fuel, is that about right?
Cheers
Andrew

test.jpg2015-05-24 10.51.20.jpg2015-05-24 10.51.47.jpg

[DJT]

Mmmmm! I can smell that unleaded from here....

I would experiment with bending the sender arm to match the original one. I don't know why you've changed the sender but if ditching the old one I'd hang onto the float as they are known to fail, so at least you have a spare.

[Andrew S]

Thanks Dave, good point

I am more concerned about the tank level and not sure if members can see from my photos as to how full it is in order to judge the reading.

Cheers
Andrew

[jasper]

http://www.ebay.co.uk/itm/SOLID-STATE-VOLTAGE-STABILIZER-GT6-Spitfire-Stag-2500-/131501125330?pt=LH_DefaultDomain_3&fits=Car+Make%3ATriumph%7CModel%3AStag&hash=item1e9e13eed2

John

[pollystag]

Have you earthed the live wire from the sender unit ? If not the gauge should go up to the full mark if it doesn't it will be the gauge thats faulty.

[Andrew S]

Yes, took the wire off at the sender unit and earthed it and it went to full and over

It may well be OK but as the old sender as good as showed the tank was full and the owner said he filled it up, I presumed it was completely full. May not be the case of course. Different when its your own car as you know it.

The main thing is that it was running at a high temperature and now its idling very low so the voltage stabilizer was at fault and reads the same as mine when I swapped them over.

[Pete]

I'm fitting a solid state voltage stabiliser. I don't trust the mechanical type even though mine has been in the car for 40 years! If the contacts fuse or stick, your guages will be toast and I've spent something like £300 on new magnolia dials.

[Andrew S]

I have one of those fitted to my stag and the readings are the same. So, to test this friends stag, I fitted my old one and the readings are the same as the new stabilizer that I bought last week.

[Pete]

You have been concentrating on the fuel sender. What does the temperature gauge read with either stabiliser when the engine is cold? Do you have a voltmeter to test the voltage from the stabiliser (do all of them)?

[Andrew S]

Hi Pete, the temp gauge reads slowly and just below a quarter. Will check readings at some point