Fuel gauge not working

[jambo_sri130]

Like I say, my fuel gauge has decided it's had enough. Does anyone know how to get it working again?

[Cavalier342]

This could be a multi-choice option. You could get behind the dash and check out the electric connections, but it could also be the fuel sender unit. I'm not sure if its the same on all cars, but on my old Citroen ZX, the gauge wasnt working. The fault was 100% the sender unit, however when the fuel was low, the warning light still activated. So hopefully its the same on all cars.
Hope this helps. Andrei

[crocadmin]

id put money on the sender, its a common fault with older vauxhalls its not something that can be fixed....either 1 from a scrappy or a new 1

[jambo_sri130]

Ok, how do I find the sender and what does it look like? The Haynes manual isn't very descriptive

[Squig]

what car is it

[jambo_sri130]

2.0 8v. Mate said it is with the pump under the rear seat but the manual says it's beside the tank. I dunno what the sender looks like exactly so should find that out first

[Gaz]

8v tend to be at the side, the sender is in the same place on all of them

[Robsey]

As far as my memory serves it should be similar to my car...
Mine is a 1.8 CFi with the pump in the top of the tank (under rear seat)...
The sender for this is at the rear of the tank on my car with an oval plug on it.

Firstly check your connector and wires for corrosion or snapped conductors...
but as rightly said above, I would consider that the sender itself is probably tatered, especially if you run on approx 1/4 to 1/2 tank all the time...the variable resistance contact surface wears out / gets rubbed away.

[Robsey]

Any results with this...

If it is a sender fault, then disconnect the plug from sender and put a 120 ohm resister across the pins in the plug. (turn on the ignition of course..but use a decent wattage resister otherwise it will get quite hot)
The gauge on the dash should register just above the red..approx 70miles in the tank.

If not, then it is a loom, connection fault...behind the insrument cluster, or the sender plug connector itself.
If it is the sender connector check for broken or dirty contacts / pins...clean and smear with vaseline / petroleum jelly.

Not usually the gauge itself, but there are plenty in Cav and Astra III's in the scrap yards if you want to try another one.

[jambo_sri130]

Yeah it's sorted bud. The problem was none of the above hehe It turns out I hadn't been putting in enough petrol for the needle to move! hahahaaaa I only ever put a tenner at a time in and it wasn't until I had to put in about 20 quid that I realised it was workin fine! Feel like a right numpty now lol

[Gaz]

Mine lives on £10/£20 as the tank leaks otherwise

[Cavalier342]

is there any harm in running with 1/4 to 1/2 full then? i normally have it between 1/2 and 3/4 full, or more and top it up every now and then.

[Gaz]

Nope tbh its probably worth running it low a few times and then filling up, then changing the fuel filter.

[Cavalier342]

Ye the fuel filter i will change at some point, its all corroded and rusty and just generally needing replacement. I read somewhere that if its clogged and hasnt been replaced for a while, it can affect engine performance because the fuel pump is working harder to get fuel across. If i replace it, would i feel a bit more kick under power?

[Gaz]

If its that clogged then yes you will.

[Cavalier342]

thats that then. Got my MOT like next month, so i'm hoping to get it done and a good run before that. I've had the car almost 2 years, but the amount of rust around the filter suggests it hasnt been looked at recently lol.

cheers Gaz

[Squig]

brilliant, that's like someone I know complaining the heater was broken as it never blew hot and her car continually overheated... so I put water in the coolant system. Novel solution.

[Cavalier342]

[Envoy CDX]

Fuel filters about £11 Andrei

[Cavalier342]

wanna bet?
£4.11 at Euro Car Parts here
come on payday!!! lol. i wanna fit a new one before the MOT for emissions sake.

[Cavalier342]

well i fitted a new one on. i think i got the flow direction arrow the right way, the arrow is facing left if looked from the back of the car. Gave it a good fast idle, 2500rpm for a minute or so. Hopefully i'll notice a bit more power and economy now when i next fill her up. The amount of black sooty dirt that leaked from the old filter was amazing.

[Squig]

the arrow indicates the fuel flow direction so should face from tank to engine.

[Cavalier342]

How often should the filter be changed anyway? i've read that its at "regular intervals" but how regular, to keep optimum engine performance.
thanks.

[Gaz]

depends, i wouldnt bother with less than every 15kmiles.

[Cavalier342]

cool thanks.
I'm normally driving around town, regular fuel, etc. from now on. i'll just do it with the regular service, 9k miles or so.