Funny fuel gauge

Boltonboy · 18th September 2020, 19:44

My fuel gauge seems to be wacky goes up and down all the time I have run diagnostic test with cars odo computer my test revealed that the fuel tank sensor on the left is malfunctioning any advice you can give me would be greatly received .

I would probably take this to a professional for fixing is there a rover mg specialist in Wigan I used him before for my zt but have forgotten his details any ideas.

trikey · 18th September 2020, 20:24

Sounds like the in tank pump has been replaced to me, if you are not 100% sure what you are doing with these, then you will end up with an erratic fuel gauge.

Boltonboy · 18th September 2020, 23:24

Hi mate

Thanks for the advice i thought it would be these are really tricky the owner previously just used a local garage not specialist so makes sense

Just to clarify how would you go about sorting this out any advice really appreciated

trikey · 19th September 2020, 08:32

It depends if the float mechanism has been damaged during the fit.

It could be as simple as re seating the assembly correctly, or it may need a new unit, the only way to tell is to open the lid and have a look to see if any wires are routed incorrectly or the pickup isn’t seated where it should be

gnu · 19th September 2020, 08:44

I agree with Trikey. My fuel gauge started playing up after I brimmed the tank. In this case it was the filter side (LHS) causing the problem. I just took the filter out (fitted an orange clip - a job I was planning anyway) carefully refitted and it worked fine again. No replacement parts required.

I'm now a bit more careful not to run the tank too low or brim it, as that seemed to start the problem.

Boltonboy · 19th September 2020, 11:05

Thank you for your advice I will investigate further

T-Cut · 19th September 2020, 16:14

There was a great How To on fixing an erratic gauge, that explains one common issue causing this and describes the fix for a worn/broken float rheostat. Unfortunately, all the images in the HowTo are no longer available, but maybe the adjoining text will help.

HowTo (text part only): https://www.the75andztclub.co.uk/for...d.php?t=194156

Here's a couple of my own photos that show what bit is involved:

Check that the spring brush contacts the resistor wires all the way from end to end.

There's also the resistance check you can do using an ohm meter on the tank connector. However, you do need access to the floats to operate them manually.

TC

Boltonboy · 19th September 2020, 18:41

Cheers mate for pictures and advice greatly appreciated

Boltonboy · 21st September 2020, 18:08

I have decided to take it to pk automotive in Wigan for fuel sensor sorting
Paul seems to know his stuff being a rover trained main dealer mechanic I used him before for my fuel pump on my mg zt which he fixed no problem and I have a few other bits for him to do and he will lend me another car usually a rover 25 all booked in

18th September 2020, 19:44	#1
Boltonboy Avid contributor Rover 75 classic se cdti\ mg zt 120 /rover 75 club 1.8 Join Date: Aug 2020 Location: Bolton Posts: 166 Thanks: 85 Thanked 13 Times in 10 Posts	Funny fuel gauge My fuel gauge seems to be wacky goes up and down all the time I have run diagnostic test with cars odo computer my test revealed that the fuel tank sensor on the left is malfunctioning any advice you can give me would be greatly received . I would probably take this to a professional for fixing is there a rover mg specialist in Wigan I used him before for my zt but have forgotten his details any ideas.

18th September 2020, 20:24	#2
trikey Premium Trader Rover 75 Join Date: Nov 2010 Location: Devon Posts: 33,765 Thanks: 8,837 Thanked 14,831 Times in 8,030 Posts	Sounds like the in tank pump has been replaced to me, if you are not 100% sure what you are doing with these, then you will end up with an erratic fuel gauge. __________________ Lest we forget..

18th September 2020, 23:24	#3
Boltonboy Avid contributor Rover 75 classic se cdti\ mg zt 120 /rover 75 club 1.8 Join Date: Aug 2020 Location: Bolton Posts: 166 Thanks: 85 Thanked 13 Times in 10 Posts	Hi mate Thanks for the advice i thought it would be these are really tricky the owner previously just used a local garage not specialist so makes sense Just to clarify how would you go about sorting this out any advice really appreciated Last edited by Boltonboy; 19th September 2020 at 00:17..

19th September 2020, 08:32	#4
trikey Premium Trader Rover 75 Join Date: Nov 2010 Location: Devon Posts: 33,765 Thanks: 8,837 Thanked 14,831 Times in 8,030 Posts	It depends if the float mechanism has been damaged during the fit. It could be as simple as re seating the assembly correctly, or it may need a new unit, the only way to tell is to open the lid and have a look to see if any wires are routed incorrectly or the pickup isn’t seated where it should be __________________ Lest we forget..

19th September 2020, 08:44	#5
gnu Gets stuck in MG ZT Join Date: Apr 2018 Location: Bristol Posts: 695 Thanks: 332 Thanked 164 Times in 133 Posts	I agree with Trikey. My fuel gauge started playing up after I brimmed the tank. In this case it was the filter side (LHS) causing the problem. I just took the filter out (fitted an orange clip - a job I was planning anyway) carefully refitted and it worked fine again. No replacement parts required. I'm now a bit more careful not to run the tank too low or brim it, as that seemed to start the problem. __________________ gnu

19th September 2020, 11:05	#6
Boltonboy Avid contributor Rover 75 classic se cdti\ mg zt 120 /rover 75 club 1.8 Join Date: Aug 2020 Location: Bolton Posts: 166 Thanks: 85 Thanked 13 Times in 10 Posts	Thank you for your advice I will investigate further

19th September 2020, 16:14	#7
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,752 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	There was a great How To on fixing an erratic gauge, that explains one common issue causing this and describes the fix for a worn/broken float rheostat. Unfortunately, all the images in the HowTo are no longer available, but maybe the adjoining text will help. HowTo (text part only): https://www.the75andztclub.co.uk/for...d.php?t=194156 Here's a couple of my own photos that show what bit is involved: Check that the spring brush contacts the resistor wires all the way from end to end. There's also the resistance check you can do using an ohm meter on the tank connector. However, you do need access to the floats to operate them manually. TC Last edited by T-Cut; 19th September 2020 at 16:20..

19th September 2020, 18:41	#8
Boltonboy Avid contributor Rover 75 classic se cdti\ mg zt 120 /rover 75 club 1.8 Join Date: Aug 2020 Location: Bolton Posts: 166 Thanks: 85 Thanked 13 Times in 10 Posts	Cheers mate for pictures and advice greatly appreciated

21st September 2020, 18:08	#9
Boltonboy Avid contributor Rover 75 classic se cdti\ mg zt 120 /rover 75 club 1.8 Join Date: Aug 2020 Location: Bolton Posts: 166 Thanks: 85 Thanked 13 Times in 10 Posts	I have decided to take it to pk automotive in Wigan for fuel sensor sorting Paul seems to know his stuff being a rover trained main dealer mechanic I used him before for my fuel pump on my mg zt which he fixed no problem and I have a few other bits for him to do and he will lend me another car usually a rover 25 all booked in