11 replies to this topic

[Marky Tizz]

Yes I know this has been asked 10000 times but I have searched, read everything I can find, followed all the advice, and I can't seem to work it out still.

 

Mini is a 1989 Mini 30. Clocks aren't original but they are the same model as original, and the fuel gauge used to work fine.

 

As it is today, when full, it sits about halfway, half tank is empty, empty is bottom of the gauge. I've been getting by just relying on that being correct but it's annoying me a bit now.

 

We have tried a new sender unit, no difference.

 

So I tried all the wiring at the sender end as follows:

 

"Use a short jumper wire between the green/black wire on the sending unit and the battery earth connection. If the gauge goes to "full" while the green/black wire is earthed then the problem will be with the sending unit or its earth connection. To determine which, remove the jumper wire from the battery and connect it to the black wire on the sending unit. If the gauge goes to full again, your problem is in the sending unit. If it does not go to full, the problem is with the black wire or its earth connection."

 

These steps did make a difference, but the gauge stops about 3/4 of the way. Initially it was more like 7/8 (1st pic), then I realised I had used about 10 litres yesterday so I went and topped it up. Came back tried again, now sits around 3/4 (2nd pic). I was hoping it would hit full...

 

I have also tried adding a wire to a known earth point rather than just the battery, exactly the same. 

 

This would make me think it's the voltage stabiliser at the clock end, but the temp gauge works perfectly. So, any ideas/more things to try?!

 

 

 PXL_20230522_122342428.jpg   32.77K   2 downloads

 

 PXL_20230522_125836691.jpg   31.31K   1 downloads

[sonscar]

Does the arm on the sender move freely throughout the full range whilst in the tank would be my first check.Gives an excuse to use all that full ank of fuel.Steve..

[splintercat]

Got to go with the above............does the fuel gauge ever read full.

try a different gauge to see, and if not and don,t want to sound silly but if with a new sender it stays the same it must be either the gauge itself not having a full range of movement so try it with the sender not in the tank,  or the wire attached to the float needs adjusting as could be it,'s just not sitting correctly or your tank is not sitting correctly.

I expect i am talking utter c22p but worth a try IMO.

[Spider]

I'd be testing that the Gauge is being fed with a full 10 volts. Sounds like it's getting less.

[Marky Tizz]

Got to go with the above............does the fuel gauge ever read full.

try a different gauge to see, and if not and don,t want to sound silly but if with a new sender it stays the same it must be either the gauge itself not having a full range of movement so try it with the sender not in the tank,  or the wire attached to the float needs adjusting as could be it,'s just not sitting correctly or your tank is not sitting correctly.

I expect i am talking utter c22p but worth a try IMO.

 

 

I'd be testing that the Gauge is being fed with a full 10 volts. Sounds like it's getting less.

 

Thanks for the feedback

 

OK so next step I will try a different sender with the extra earth.

 

Then try to measure the voltage at the gauge - is this literally gauges out, multi meter to the back of the clock?

[Spider]

 

Got to go with the above............does the fuel gauge ever read full.

try a different gauge to see, and if not and don,t want to sound silly but if with a new sender it stays the same it must be either the gauge itself not having a full range of movement so try it with the sender not in the tank,  or the wire attached to the float needs adjusting as could be it,'s just not sitting correctly or your tank is not sitting correctly.

I expect i am talking utter c22p but worth a try IMO.

 

 

I'd be testing that the Gauge is being fed with a full 10 volts. Sounds like it's getting less.

 

Thanks for the feedback

 

OK so next step I will try a different sender with the extra earth.

 

Then try to measure the voltage at the gauge - is this literally gauges out, multi meter to the back of the clock?

 

If when shorting the Green/Black to Earth the Gauge doesn't go off the full end of the scale, then the issue isn't the sender but either the supply to the gauge or the gauge itself.

Measuring the 10V can be tricky if the original stabaliser is fitted as they don't really drop the voltage but pulse 12V in the right on/off periods so that it's an average of 10V. Checking it with a Multimeter will usually give odd readings that make no sense. Ideally, you need a thermal type voltmeter, like a Smiths unit to measure it with. The replacement Stabalisers these days seem to be electronic and do give a true 10 Volt output. If you have a Smiths Voltmeter or can borrow one, then use that, but otherwise, it might work out cheaper to replace the Stabaliser.

[Marky Tizz]

 

Measuring the 10V can be tricky if the original stabaliser is fitted as they don't really drop the voltage but pulse 12V in the right on/off periods so that it's an average of 10V. Checking it with a Multimeter will usually give odd readings that make no sense. Ideally, you need a thermal type voltmeter, like a Smiths unit to measure it with. The replacement Stabalisers these days seem to be electronic and do give a true 10 Volt output. If you have a Smiths Voltmeter or can borrow one, then use that, but otherwise, it might work out cheaper to replace the Stabaliser.

 

 

OK and when you say replace the stabiliser, you mean wiring in one as per this link: https://www.theminif...tage-regulator/

?

 

I do have a spare set of gauges so I will try that also, but I've no guarantee they work either as taken off the car about 14 years ago (they are the originals)

 

Thanks for help

[Spider]

If your gauges are the Nippon type, yes.

If you have Smiths gauges, then it would be something like this;-

 

http://www.minispare...px|Back to shop

 

[Marky Tizz]

If your gauges are the Nippon type, yes.

If you have Smiths gauges, then it would be something like this;-

 

http://www.minispare...px|Back to shop

 

Thanks Spider. I'm 99.9% sure they're Nippon. Guess I better get the soldering iron out.

[Marky Tizz]

Update: I tested my other set of gauges, seem to work fine. So I set about installing the voltage stabiliser, which took a lot longer than I thought it would!

 

Unfortunately it hasn't fixed the problem. The gauge will read slightly higher than before now, but still doesn't look accurate (especially compared to the other gauge). I also managed to drop a screwdriver on the temp gauge which now doesn't sit at the bottom of the range when cold...

 

So for the time being I have the original (spare) gauges rested on the dash shelf while I decide what to do. I need a new dash anyway as the one I removed is split, but I was hoping to avoid cutting the indicator tubes on the originals. Looking at prices of the clusters though I think I might have a date with a dremel...

[splintercat]

why didn't you try fitting a solid chip in place of the original wire vibrating stabiliser, definately get a steadier and more reliable 10v at the gauge, cheaper too.

[Marky Tizz]

why didn't you try fitting a solid chip in place of the original wire vibrating stabiliser, definately get a steadier and more reliable 10v at the gauge, cheaper too.

 

Is that not what I did by following this link? https://www.theminif...tage-regulator/