my mk2 golf g60 has always read about 1/5 low on the fuel gauge....so it shows empty when i still have some
ive just swapped in another gauge and its the same
would i be right in thinking theres only the float sender left to change? is it all in one piece? any other ideas
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its a good bet that the sender unit has gone - its should be reletivly easy to replace IIRC, on the VW Polo it was a case of lifting the back seat over, and simply screwing it out of the tank, however it could be different on the Golf
BUT - Remeber to disconnect the battery - fuel and stray electrical sparks do not mix!!!!
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1983 (A) Vauxhall Astra 1.3L
1993 (K) Vauxhall Cavalier 2.0i GLS
1999 (T) Renault Laguna 1.6
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The other obvios thing to check is the earth from the sender - a high resistance connection, or poor earth, will cause exactly this fault.
Number_Cruncher
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On fuel injected mark 2 Golfs the fuel gauge sender supports the 'in-tank' fuel pump. The G60 may be different.
Do you want to tamper with part of the fuel injection system for the sake of a gauge reading error. The sender is simply a wire arm with a float on the end which moves a rheostat. You could alter the output by bending the arm.
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right ive had a fiddle and have some more info
i whipped out the sender...the tank really was full of fuel!! , i tested the resistance on the slider scale on the float...it read higher for each segment nearer to full as you would expect
i also stuck my hand in there and can confirm the float was fully up ...and with the flaot mech out of the tank and cranked into the full position it still wouldnt read full
to me it seems the float works as it should and theres a incompatiblity fault between the gauge and sender
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The current has to go to earth to complete the circuit - is this earth point OK?
Number_Cruncher
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Some cars have a stabilised voltage supply to feed the gauges to ensure that fluctuations in the battery voltage do not get reflected in the readings. It is just possible that this solid stae regulator has become defective. Check the supply voltage at the gauge and see if a Haynes wiring diagram gives a clue.
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pmh (was peter)
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So when you have approx 2 gallons of fuel left the tank reads empty? Sounds about right to me.
If the voltage stabilizer (its 3 legged electronic component on the rear of the dash clocks) was faulty the gauge would read higher when the engine was running due to a higher charge rate from the alternator.
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dox yeah it shows bottom of red with £12 in it, and it shows 3/4 with it completley full
the gauge has never been accurate , it caused me to run out of fuel the other day...while i dont make a habit of running around on fumes , id like it to be more accurate than it is
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If its anything like the other wiring on mk2s the wires to the tank will have gone high resistance, how dim are your headlamps LOL ;-)
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the headlamps are sweet....ive relayed em !
never heard of the fuel gauge issue on any other mk2 or similar age vw
not really sure what to do now :(
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Can you reposition the needle on the gauge? Ie bend the needle?
If you earth the gauge directly does the gauge read full?
SPARKS AND PETRIOL FUMES DON'T MIX (other than inside the engine) SO DON'T DO THIS WITH THE SENDER / PUMP UNIT REMOVED FROM THE TANK AND A BOOT FULL OF PETROL FUMES. Be safe not sorry!
That was a warning and not shouting (anyone can read this thread not just the original poster) ;-)
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>>not really sure what to do now :(
How good is the earth connection?
Number_Cruncher
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How good is the earth connection?
Try shouting a little louder NC ;-)
--------------
Mike Farrow
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....If the voltage stabilizer (its 3 legged electronic component on the rear of the dash clocks) was faulty the gauge would read higher when the engine was running due to a higher charge rate from the alternator.....
Only if the regulator was not regulating!
If the output voltage was low (or effectively a series resistance was present any where after the regulation), the gauge would read LOW.
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pmh (was peter)
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hmmmm i have another cluster that i can rob the voltage reg from...i will try that
i have a question about resistance ....its above me
the gauge operates from lets sat 100ohms empty to 250 ohms full......if the wiring had a higher resistance than normal would that make the gauge over read? or under read
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If your figures are correct (and not reversed) a series resistance in the earth lead (or anywhere else) will make the gauge reading appear high.
Are you sure that you have the figures the correct way round?
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pmh (was peter)
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>>Are you sure that you have the figures the correct way round?
Good question!
Most fuel and temperature gauges are, in effect, ammeters. They are supplied via a regulator with a fixed voltage, and the resistance of the sensor determines the current. in the circuit.
Therefore, it most common for sensors to have their highest resistance when either cold, or empty depending upon application. If this is the scenario with the Golf, then a poor connection anywhere in the circuit would cause a low reading.
This is why I've been banging on about earth connections.
Number_Cruncher
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This is why I've been banging on about earth connections. Number_Cruncher
Its also why I recommended the OP removed the plug from the tank and earthed it, no resistance should give a full tank reading
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Only if the regulator was not regulating! If the output voltage was low (or effectively a series resistance was present any where after the regulation), the gauge would read LOW.
OP does'nt complain of temp gauge reading low, the regulator works on the temp gauge too does'nt it?
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now you mention it....i guess the coolant gauge maybe a touch on the low side, id never though about it before..although golf temp gauges are never consistant
dox you say earth it....im not quiete sure what to earth?? the multiplug has 4 wires...i assume its 12v an earth and 2 leads for the gauge??
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If you disconnect the plug and switch the ignition on
When you turn on the ignition, you will get a 12v pulse down one of the wires for a few seconds - this corresponds to the brief running of the fuel pump.
On another of the wires, you will get about 10 volts(if you measure it with a decent high resistance voltmeter so you don't draw any appreciable current) - this is the regulated voltage. This is the wire to connect to earth.
Check the wiring diagram for your car, to make sure.
Number_Cruncher
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slight update if anyone cares.....
ive just checked the regulator and its spot on
i was hoping to trace the wiring to the clocks....thing is the colors at the tank are brwn/blue and purlpe/blk.....these colors do not exsist at the clock plug? i imagined it would be a direct run? no need to change color or go via the fuse box ??
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Have you tried it with the spare gauge yet?
I think I would give up and just bend the pointer on the existing petrol gauge about 25% to the right!
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pmh (was peter)
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yes its on the second gauge now...i actualy tried to bend the first one and thought it was better till i ran out of fuel :(
ive got yet another one im going to swap into it now....im not sure if differant years/makes of clusters matter
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ok any opinions on this? ive taken the gauge out of the cluster so i can fiddle without pulling the cluster apart each time
img.photobucket.com/albums/v20/pigbladder/cluster....g
then with the face off the guage it appears to have room for ajustement
img.photobucket.com/albums/v20/pigbladder/dial2.jpg
img.photobucket.com/albums/v20/pigbladder/dial.jpg
cant really figure out waht moves what just yet....any ideas
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You do not have to bend the pointer! They have provided for screwdriver (flat blade) adjustment, in the hole with the 'ratchet' shown in dial2 picture.
Just insert screwdriver and gently twist.
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pmh (was peter)
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