Sticky fuel guage.

[Nuvo]

When starting the car first thing in the morning the fuel gauge reads much lower than it should with the car being parked on level ground. The expected reading can be seen after a while, I can't be certain if driving up and down a few inclines restores normal operation or if it's purely coincidental.

I'm wondering if I took the fuel sender out and gave the resistive strip a clean or maybe the float mechanism is somehow sticking. Anyone else seen this before and fixed it?

Thanks,
Rob.

[re2500]

The way to tell if it is to do with your guage or your tank float sensor would probably be to see if your range changes also. If it does i would say float if it doesnt i would say guage...

[BosnianS2]

From my experience it seems that this is normal. After you drive for while (1-2 km) gauge reads fine??

[Nuvo]

Its definitely not normal behaviour as it can be 10 miles or so before the gauge shows the right level. On the odd occasion it works normally on the turn of the key. When I get a chance to look at it properly I'll report my findings in this thread.

[maddagent]

My 80 Cab does the exact same thing with the fuel gauge, I never did get round to finding out why but i'm sure its not normal!!

I can put half a tank in and it will read normal leaving the petrol station but read 1/4 full 2 mins up the road, then back to half full by the time I'm home (say another 5 mins!)

Total mind of its own lol.

D

[newsh]

You need to make sure that the regulator on the back of the instrument cluster has a good ground. It is bolted down with the screw through a bush. I drilled the bush out and used a washer and I've had no random readings since. If you have this problem the temp gauge will be random too though..

[newsh]

Just a thought. It's not the white paint on the gauge face flaking is it?

[Nuvo]

The temp gauge is working okay. The car is a regular coupe with black dial faces so no peeling as seen with the grey dials on S2s. I have a spare instrument cluster I could drop to see if the fault clears and work from there.

The only anomaly is the fuel pump whilst quite noisy can be heard make a change in sound from time to time, not sure if it is relevant but thought I'd mention it just in case there could be a link.

[BosnianS2]

Well mine does not take that long to show correct level, but it does not react as fast as some newer cars, that is why i commented as that being normal. Now that you said that it takes really long time, i agree that you have problem.
Are you familiar with fact that our gauges are also influenced by driving style, i mean that they will show less fuel if you are driving fast in order to give driver better idea how far can he/she make it with current driving style?

Maybe you have problem related to this feature. Have you noticed difference if you drive off fast or slow in gauge behaviour?

[Error404]

Mine used to be really slow until I cleaned the contact strip on he tank sender, now it registers the correct fuel level in about 15 second

[Nuvo]

You need to make sure that the regulator on the back of the instrument cluster has a good ground. It is bolted down with the screw through a bush. I drilled the bush out and used a washer and I've had no random readings since. If you have this problem the temp gauge will be random too though..

Good tip, I wish I had rememberd to to check the regulator bush today when measuring its terminal voltages. The regulated voltage was in spec at 9.99V with the supply/battery voltage reading lower than expected at 11.77V.
So it appears that I have around a 1V loss in in the wiring between the battery and the instrument cluster. Is this an acceptable loss to see in an old car? Seems on the gigh side considering the cable length.

Unfortunately I didn't have the time to check the voltage at the sender today.

[Nuvo]

Mine used to be really slow until I cleaned the contact strip on he tank sender, now it registers the correct fuel level in about 15 second

This is what I suspect to be a fault with mine too. I hope to check this and measure the sender voltage tomorrow.

[Nuvo]

Well I can close this out I just cleaned the two washers at the rear of the fuel guage, Remove one screw and clean the washer with IPA and refit and repeat with the second one. I did it this way to prevent the guage from dropping to floor.

[Mr G]

Hi Nuvo - I have a similar problem on my RS2. At times it will show that the tank is almost empty, put in 10 litres and it goes to over half a tank.
I assume you had to remove the instrument cluster to get to the washers?
I've also experienced the "driving" hard and the gauge level dropping, and the range reduces dramatically

[Nuvo]

Yes, that's right, I removed the instrument cluster to do this.