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Model specific boards => Golf mk2 => Topic started by: Gozza on 10 December 2003, 17:10

Title: Testing my fuel gauge
Post by: Gozza on 10 December 2003, 17:10

Hi all my fuel gauge does not work and it is starting to get on my titties. I had the dash out the other day to make sure nothing had come disconnect and all seemed fine. I think the obvious thing to do would be to test the wiring etc with a circuit tester. Anyone ver had the same problem before ?? If so, how did you solve it ??

Thanks all.
Title: Re:Testing my fuel gauge
Post by: golfvr6 on 10 December 2003, 17:16
Probably need a new sender unit, it is in the fuel tank with lift pump(if fitted).
Title: Re:Testing my fuel gauge
Post by: Gozza on 10 December 2003, 19:38
Is this difficult to replace and if so how much does it cost ??

I have been told euro car parts dont do it so............ :(
Title: Re:Testing my fuel gauge
Post by: golfvr6 on 10 December 2003, 22:00
You will have to remove the unit from the tank, and test for continuity. I think its behind the rear seats, the removable base on top of the fuel tank that is.
The other easy test you can do is disconnect the wiring from the sender unit, bridge the points with a paper clip(with ignition on). If nothing happens then its not the sender and instead a wiring fault.
Title: Re:Testing my fuel gauge
Post by: Gozza on 11 December 2003, 12:11
Thanks for the info.

I removed the cover in the boot the other day and there was a clip with 2/3 wires going into the tank, is this the wiring you refer to ??

Also if I use a circuit tester on these wires should they have charge? if they do are they working ok ?


Thx
Title: Re:Testing my fuel gauge
Post by: Gozza on 12 December 2003, 12:18
:)
Title: Re:Testing my fuel gauge
Post by: golfvr6 on 12 December 2003, 17:00
I'll check the wiring diagram if i get the chance later  ;)
Title: Re:Testing my fuel gauge
Post by: Gozza on 15 December 2003, 14:23
had a look at the wiring to the fuel tank today and consists of the following wires,

Brown - Earth
Purple n Black - dunno
Red n Yellow - Power when car running, nothing when ignition on/car off

Now I was contemplating connecting the purple n black and ren yellow as I assume this will give power to the gauge then tell me if the gauge is ok or if I need a sender unit or not, is this right ??

BY the way my Petrol pump hums constantly, does this mean its about to go or what ? Has been like it since i bought it and the guy before said it has been like it since he has owned it ?? any idea ??

Thx
Title: Re:Testing my fuel gauge
Post by: richandhazel on 15 December 2003, 15:48
Violet and black is the lead that provides the input to the gauge from the sender unit.

Red and yellow is the power supply to your lift pump.

I may have the wrong diagram here, but are you sure the other lead is brown only? Or is it black and brown?

(http://homepage.ntlworld.com/richandhazel1/golfgti/genpics/sender.JPG)

If its black and brown then I'd have another look at the wiring diagrams as I don't think it'll be a straight earth........according to the above diagram, it goes to current track 124, not straight to earth.

Main fuel pump will hum all the time..........that's normal.


Title: Re:Testing my fuel gauge
Post by: Gozza on 15 December 2003, 15:51
OK thanks could be black n brown I will have another look. So if I cross the purple/black n red/yellow could I tell if the guage works ?? so I can elimate the problem being the gauge or sender ? ???
Title: Re:Testing my fuel gauge
Post by: richandhazel on 15 December 2003, 15:57
I would trace through the wiring diagram and find out where current track 124 goes first.
You might do damage.
Title: Re:Testing my fuel gauge
Post by: Gozza on 15 December 2003, 17:12
Ah fecking hate wiring diagrams. Vr did you hav any luck in looking at de wiring ??

Thx all
Title: Re:Testing my fuel gauge
Post by: Gozza on 17 December 2003, 14:22
 ??? ??? ??? VR6 u found out  ??? ??? ???
Title: Re:Testing my fuel gauge
Post by: golfvr6 on 17 December 2003, 14:25
Ok mate, i haven't forgotten, busy with the baby at the moment, i'll have a look later .
Ho Ho Ho  :D
Title: Re:Testing my fuel gauge
Post by: Gozza on 17 December 2003, 14:39

Thx me ol china, I only ask as yesterday I over filled the petrol tank and stood there thinking how shinny my tyres looked. Doh, it was the petrol running down the side  ::)

Tis driving me MENTAL  :-X
Title: Re:Testing my fuel gauge
Post by: richandhazel on 17 December 2003, 15:26
Have you tried pulling the sender unit out of the tank yet? You may find that the float is punctured, full of fuel and therefore sitting at the bottom of the tank...........just a thought :-\
Title: Re:Testing my fuel gauge
Post by: Gozza on 17 December 2003, 15:51
Would this be difficult to do. I have taken the metal lid off the wiring and it looks like I could undo the attached hoses and then unscrew it. If I unscrew it would this bring the sender unit out so I could check it ??

Thx
Title: Re:Testing my fuel gauge
Post by: richandhazel on 17 December 2003, 15:56
Yes it would, it should all come out as one unit. In fact you may not have to undo the pipes as the lock ring can turn independantly of the rest of the unit......if you get my drift.

Only thing to be wary of is that it can be very tight and you wouldn't be the first to have broken the lock ring in trying to get it off...........you might be lucky and it may not be that tight.
Title: Re:Testing my fuel gauge
Post by: Gozza on 17 December 2003, 16:14
OK thx, I will have a look later n see. If it is loose I will have a butchers if not I am leaving it well alone, I have lost track of the number of things I have broken due to sheer clumsyness on my cars. If I am unable to loosen it I will have to stick to trying to test the gauge. At least then if that works I will know for sure I have to risk it.

Cheers
Title: Re:Testing my fuel gauge
Post by: golfvr6 on 17 December 2003, 22:40
had a look at the wiring to the fuel tank today and consists of the following wires,

Brown - Earth
Purple n Black - dunno
Red n Yellow - Power when car running, nothing when ignition on/car off

Now I was contemplating connecting the purple n black and ren yellow as I assume this will give power to the gauge then tell me if the gauge is ok or if I need a sender unit or not, is this right ??

BY the way my Petrol pump hums constantly, does this mean its about to go or what ? Has been like it since i bought it and the guy before said it has been like it since he has owned it ?? any idea ??

Thx

Alright geezer, just looked at the wiring diagram, the sender unit is a variable resistor. The purple/black and the brown wires are the ones for the sender unit. Firstly disconnect the wiring plug.
In theory if you connect the 2 points on the wiring plug with ignition on then you are bypassing the resistor and as there will virtually 0 resistance your fuel gauge should register full.
I'm not totally sure but this is what i think.
Anyone? RICH?
Title: Re:Testing my fuel gauge
Post by: richandhazel on 18 December 2003, 01:34
I agree with '6 there, you're need to connect the purple/black to earth (brown) rather than a +ve supply. If you connect that purple/black to a +ve supply, you may well do damage to your gauge and or associated components.

As '6 says the sender unit is a variable resistor, so another thing you may want to try is connecting an ohmeter between the two connections on the sender unit itself and measuring the resistance of the variable resistor. Then after you have used some fuel, try measuring it again. I would imagine that with a full tank you will have high resistance and with an empty tank, low resistance.........although knowing my luck it'll be the other way round.........either way you should see a change in resistance as you use the fuel.

Title: Re:Testing my fuel gauge
Post by: Gozza on 18 December 2003, 09:27
Ok thx lads, I will try connecting the wires as you say and see what happens.

Thx for ya help :)
Title: Re:Testing my fuel gauge
Post by: golfvr6 on 19 December 2003, 21:11
Any luck with it?
Title: Re:Testing my fuel gauge
Post by: Gozza on 20 December 2003, 09:50
Not so far matey, gonna try n have a look either today or tomorrow. Bloody raining again at the mo :(.

Will let ya know once I sort it........hopefully  ::)

CHeers
Title: Re:Testing my fuel gauge
Post by: Gozza on 21 December 2003, 18:29

had a look today and crossed the two wires as you suggested and nothing, petrol gauge did not even move at all. Any idea if this means my gauge is shafted ??

Also tried to undo the colar on the petrol tank and is well fkin tight :(

Thx
Title: Re:Testing my fuel gauge
Post by: golfvr6 on 21 December 2003, 22:28
Have you checked where it connects in the dash. Otherwise there must be a wire break somewhere.
Title: Re:Testing my fuel gauge
Post by: richandhazel on 22 December 2003, 15:07
Did you try a resistance check at the sender unit? At least that would confirm whether you need to remove that colar or not.
Title: Re:Testing my fuel gauge
Post by: Gozza on 22 December 2003, 21:43
Nah I dont have a tester, been meaning to get one for ages. perhaps this is the perfect opportunity !! ;)