Fuel gauge problem

[streaky]

I've not experienced this before, so some assistance would be appreciated.

My fuel gauge has been 'accurate' to date - ie. it indicates full when the tanks are full and the level displayed declines as fuel is used. I refill 25-30 quids worth when the gauge displays less than 1/2 full (or more than 1/2 empty if that is your preference ).

On Tuesday last - the night of the rain (see thread) which the rev-erend will probably say is the cause of my problem<<<<<<< challenge - I filled up on my way back from Zumerzet. Yesterday I drove to Swindon. On leaving home the gauge read over 3/4 full - which I expected. Arriving in Swindon and parking I noted that it read just over 1/2 full - again which I expected.

However, as I was driving back from Swindon (steady speed, level road) I noticed that it was reading 3/4 full. Experimentation on leaving the M4 showed that the level recorded appeared to be influenced by speed (at rest 1/2, at speed 3/4). (De-)Acceleration/cornering was not a factor in the reading. The reading at rest on my return home was just under 1/2 - which is higher than usual for the miles covered.

Anyone else had this experience and more importantly have a diagnosis/cure for it?

Thanks - Streaky

>>> Edited by streaky on Friday 28th November 13:35

[jmorgan]

Mine is all over the shop. I put a gallon in during me recent problem as the gauge was in the red (not the problem as it turned out) and the gauge went up to 1/4 full. When I go up the beacons its best to make sure I have a full tank to start as there are so many up and downs and twistys the gauge doesn't no wether its comming or going.

I work to the theory that 150 miles on a good day and if its near 1/4 empty, put more in. Also I can never get the needle to full so I assume mine is reading low anyway.

[JONRES]

Yep, mine's exactly the same. When you get to the lower end of the tankfull, you either have a quarter of a tank left or below the red line, depending on whether I'm going up or down hill!

[terence]

If the gauge reading is influenced by engine speed then it may be due to a faulty voltage regulator. It may also be more pronounced when the lights, wipers heater, etc are on as battery voltage may fluctuate more, depending on the state of your charging system of course. Not sure where the regulator is on a wedge though. Usually temp and fuel gauges are regualted and possibly oil pressure if it is electric rather than mechanical. My 350 has a SEAC dash in it and as yet I have not ventured behind to see what the wiring is like. A little job after I have done outriggers and rear brakes. Hope this helps.

[wedg1e]

There is no instrument voltage stabiliser (-zer) on a wedge. The fluctuating readings probably are due to the battery voltage dropping when you first start up, then rising under charge conditions.

Ian

[streaky]

wedg1e said:

There is no instrument voltage stabiliser (-zer) on a wedge. The fluctuating readings probably are due to the battery voltage dropping when you first start up, then rising under charge conditions. Ian

Ian - I thought so too, but I'm puzzled as it's not affected by electrical load (lights, wipers, etc.) - Streaky

[rev-erend]

streaky said:

I've not experienced this before, so some assistance would be appreciated. My fuel gauge has been 'accurate' to date - ie. it indicates full when the tanks are full and the level displayed declines as fuel is used. I refill 25-30 quids worth when the gauge displays less than 1/2 full (or more than 1/2 empty if that is your preference ). You guess it .. too much roof down action in the rain.. it will probably be OK again when it all dries out ! On Tuesday last - the night of the rain (see thread) which the rev-erend will probably say is the cause of my problem<<<<<<< challenge - I filled up on my way back from Zumerzet. Yesterday I drove to Swindon. On leaving home the gauge read over 3/4 full - which I expected. Arriving in Swindon and parking I noted that it read just over 1/2 full - again which I expected. However, as I was driving back from Swindon (steady speed, level road) I noticed that it was reading 3/4 full. Experimentation on leaving the M4 showed that the level recorded appeared to be influenced by speed (at rest 1/2, at speed 3/4). (De-)Acceleration/cornering was not a factor in the reading. The reading at rest on my return home was just under 1/2 - which is higher than usual for the miles covered. Anyone else had this experience and more importantly have a diagnosis/cure for it? Thanks - Streaky >>> Edited by streaky on Friday 28th November 13:35

[blaineuk]

mine will show almost empty but will only take about £17 to fill it up and the gauge is always moving about. the only way to check mine is with the engine of. not going to put any in for a while just going to drive around until it runs out. see weather it is a faulty gauge/sender or problem with the tanks

[shpub]

They all do that sir. Wouldn't be a proper wedge if it didn't.

The only real cure is to get the sender out and play with it. It is located in a very inaccessible place and even when adjusted will tend to swing a bit. The obvious things to do are clean the conections. . The car could also be getting its own back for sheer abuse by filling it up with water. They can be real personal like that.

[sevans]

wedg1e said:

There is no instrument voltage stabiliser (-zer) on a wedge. The fluctuating readings probably are due to the battery voltage dropping when you first start up, then rising under charge conditions. Ian

I think my 83 Tasmin has a voltage regulator on the inside of the drivers side end, where there is a mounting bar. It also works OK, doesn't fluctuate or give false readings.

[streaky]

shpub said:

... The car could also be getting its own back for sheer abuse by filling it up with water. They can be real personal like that.

, but on reflection, - Streaky

[isp350]

my fuel gauge has never worked in my 350 (they were never that acurate in my Chimaera or S2 thinking about it !)so I simply make a note of the mileage every time I fill up and make sure there is a petrol station around when I've done about 180/200 miles.Having said that I have run out once ,cost me £37.37 (48ltrs)to fill it up and a huge amount of embarrasment .Thanks to the old bloke in the jag for stopping by the way !