Petrol Gauge Problem??

matsportline

Active Member
Dec 26, 2006
140
0
Okay guys wonder if you can help, my petrol guage is massively in accurate it runs out of petrol before the buzzer or guage gets anywhere near empty! say 90 miles left in the tank according to the computer and over a quarter on the guage!
can it be reset by vagcom is the guage in the tank knackered??
please help?, cheers Matt!
 

robreidmotors

RobReid
May 10, 2008
677
0
Lancashire
If say you fill up, and it takes ages for it to register any level has gone down it could be an easy fix.

Take in what I tell you before you do any of this as you are dealing with petrol!

In the boot under the carpet should be a hatch for where the fuel pump and sender goes, you can unscrew the screws on the hatch, take it off.

Underneath you will see an arrow on the plastic sender and one on the tank, these should line up, Im thinking they are not alligned and are giving you a wrong reading. If this is so do the following;

1. Disconnect the battery.

2. Losen the plastic 'ring', this is normally stubborn so use plumbers grip, or what i do is get a small block of wood and angle it onto one of the plastic ribs and hit with a hammer!.

3. When its loose enough you should be able to turn the pump sender around to lign up the markings, and then tighten the plastic ring using same method.
 

matsportline

Active Member
Dec 26, 2006
140
0
it like the guage is working but only using 3/4 of the guage if that makes any sense! it used to be very accurate! don't know whats gone wrong!
 

robreidmotors

RobReid
May 10, 2008
677
0
Lancashire
I think im right, I usually am lol.

Try the above and it should solve it, if the arrows arent lined up it will either show too little or too much depending which way off the arrow it is.
 

robreidmotors

RobReid
May 10, 2008
677
0
Lancashire
The fuel sender is a float device, to give the right reading the sender has to be alligned properly using the arrow on the sender and tank. Chances are someone has either replaced the fuel pump or had the sender out for whatever reason and has put it back without checking the arrows.
 

matsportline

Active Member
Dec 26, 2006
140
0
wierd because it didn't do it when I first got the car and no one including myself has messed with the senders on the fuel tank! It's like it needs setting to zero when there's no fuel in it! I'll let you know how I get on tomorrow!
 

matsportline

Active Member
Dec 26, 2006
140
0
Right it can't be the senders as they are in line with the arrows I think its something to do with vagcom! could it be reset by vagcom or would there show a fault with any of the senders?
 

robreidmotors

RobReid
May 10, 2008
677
0
Lancashire
Sounds like an issue with the float or float mechanism which means getting into the tank to have a look.

Could be the float mechanism is jamming or misadjusted.

To get into the tank you need to take out the fuel pump relay, turn over the car a couple of times to reduce fuel pressure, disconnect battery, disconnect in and out pipes from the sender, detach wire connector from the sender, then unscrew the plastic ring and pull out the mechanism.

Best to do this when tank is near empty, obviously you will have to guess or use chinese wisdom!

check the float itself, and then the movement of the float 'arm', and check it moves smoothly. Also check the small metal runner which generates the resistance to give the dial on the dash its reading, make sure its not broken/scored etc.
 
Last edited:
Dec 3, 2007
2,475
0
cardiff
nothing i can find on there. just been out with all i know and printouts from ross tech but nothing mate! have you tried filling it to the brim completely. then disconnect battery for 10 min and the start car and run it down. either that or there is a problem with gauge or sender
 
Dec 3, 2007
2,475
0
cardiff
turn over the car a couple of times to reduce fuel pressure, disconnect battery,

just take the filler cap off and that will be enough, but disconnect battery first before playing with any petrol.

unles you plan on having a game of russian roulette with petrol. lol
 

matsportline

Active Member
Dec 26, 2006
140
0
hmm will have to have a go my mate said to do this advice from a master tech at a stealer who he works
 

matsportline

Active Member
Dec 26, 2006
140
0
could it be the fact when i first bought the car i was pretty skint and i ran out of petrol twice and the float has jammed or collected crap preventing it from going down!
 

robreidmotors

RobReid
May 10, 2008
677
0
Lancashire
When you see where and how the sender and its float arm goes you will see how stupidly awkward it is!

Plenty of opportunity to bend the arm, or catch it on pipes etc, very fiddly.
 

matsportline

Active Member
Dec 26, 2006
140
0
or hows about filling it right up adding a fuel addative/cleaner disconnecting the battery and see what happens?