Low fuel indicator light

[gnu]

Ok, done around 285 miles from filling the tank and had time to take the rear seat up this afternoon and take some resistance measurements. Btw the fuel gauge is now reading a 1/4 full.



I don't think the Maplins meter I used is very accurate at low resistances, in that touching the probes doesn't get zero, but around 4 ohms. Also the ZT's connector block was 180 degrees different from the one in T-Cut's diagram as far as I can tell. i.e. the open side was in the car centre.

http://i5.photobucket.com/albums/y19..._Connector.jpg

RHS:



Readings were:
Pins Ohms
6-3 9
5-2 4.5
4-1 132

Quite a variation between the different sides of the tank. What should I make of it and which side's is telling porkies? 9 seems v.low and 135 seems v. high for 285 miles down on a full tank. Any ideas?

LHS:

[T-Cut]

Originally Posted by gnu

Ok, done around 285 miles from filling the tank and had time to take the rear seat up this afternoon and take some resistance measurements.

Regarding the use of Diagnostic Mode for reporting fuel tank data, there's another thread discussing this very topic, so it would be really useful if you would copy/paste the stuff you've posted here over to that one.
See: https://the75andztclub.co.uk/forum/s...d.php?t=297113
Many thanks,


TC

[T-Cut]

Originally Posted by gnu

Readings were:
Pins Ohms
6-3 9
5-2 4.5
4-1 132
Quite a variation between the different sides of the tank. What should I make of it and which side's is telling porkies? 9 seems v.low and 135 seems v. high for 285 miles down on a full tank. Any ideas?

It might be due to wear on the float rheostat windings causing a high resistance in the mid-range. This is discussed in the other thread I linked to above: https://the75andztclub.co.uk/forum/s...d.php?t=297113


TC

[gnu]

Originally Posted by T-Cut

Regarding the use of Diagnostic Mode for reporting fuel tank data, there's another thread discussing this very topic, so it would be really useful if you would copy/paste the stuff you've posted here over to that one.
See: https://the75andztclub.co.uk/forum/s...d.php?t=297113
Many thanks,


TC

Thanks for the references. I'll post this stuff there and have a go with the OBD results as well. (IPK readings etc. now added to linked thread)

[gnu]

An update on my fuel indicator problem now I've used about 2 tanks of petrol since last posting.

Since taking the original IPK readings I took the fuel filter partially out, tbh I couldn't see much under it, but hoped the movement would un-stick it. Whilst in there I fitted the FOC mod will stop the fuel-filter from unscrewing and causing a breakdown. I put it back together and took a number of IPK readings as I topped up the tank. The readings were realistic. I've added some more Redex as well. Since then the gauge has behaved, so I'm keeping my fingers crossed the problem is solved.

My recollection is that the problem started after I ran the fuel very low, then filled up and brimmed the tank. To discourage it happening again, I'm going to avoid extremes like this.

FOC mod - clip white in this case: