Fuel Gauge Wiring Query

Car 1988 GTA Turbo

My fuel gauge doesnt work. It never shows more than 9.7 galls or less than 6 galls, so I have been investigating at a superficial level

Under the bonnet, there is a little black box with a red multiplug that Lee told mw was something to do with the fuel guage. I thought I would look at it and clean up connections etc.

Here is the box



here is the label on the box



The odd think is that there are two terminals on the connector that dont line up with pins on the box

The two mpins on the right hand side of the box do not have terminals to connect to and the two terminals at the lefthand side of the plug have no pins to connect to





Surely this can't be right?

You can click the pics to see larger versions. Is the wiring wrong?, Do I have the wrong box? or something else?

Cheers

Nick

My fuel gauge doesnt work

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Try removing the sender unit - piece that inserts into the tank - and check the float is moving up and down freely.

Other than that, stick it in diagnostic mode and sling a spare petrol container in the front.

Spare can of fuel = check

Check float = job for tomorrow pm

Its the wiring that confuses me, two wires are not connected and two terminals are not connected

I'll check my wiring tomorrow for you to compare.
Mine's a1991 so wiring may or may not be the same - as these cars tend to change depending on age.

You'll probably find the sender is sticking. I free'd mine up twice now.

[BIG_MVS]

Nick, you have obviously not been given the 2009 onwards Alpine GTA Owners Manual. Under chapter 4 it explains the new way to check fuel levels on a 20 year old Alpine:

I tried that method, but its really hard whilst doing 100mph, I am not sure I get an accurate reading.


(ok its more accurate than the fuel gauge)

I'll check my wiring tomorrow for you to compare.
Mine's a1991 so wiring may or may not be the same - as these cars tend to change depending on age.

You'll probably find the sender is sticking. I free'd mine up twice now.

Thanks that would be good. By sender, I assume you mean the float think?

This is how the wires should be positioned viewed from where the wires go into the connector:-



From your pics, I cant see all the colours, but it looks as if the Black is in the right position.... the others.... not too sure.
You can reposition them by carefully inserting, say, a jewelers screwdriver into the slot at the socket side of the connector, to flatten the barb, and withdraw the wire and you then have to reset the barb, and slide it into the right hole.

Thanks John

Looking at that diagram, mine is definitely wrong, I will look at it closely tomorrow. It looks like its the tank sensor wires that are misplaced. That would explain the issue

Cheers

Nick

I would check the float and any other more straigtforward reasons for it not working before changing the wiring. The chances of a previous owner messing with wiring has to be remote doesnt it.

No two GTAs are quite the same and I wouldn't put it past them to have made a subtle change..

I'll post my wiring details later this morning.

If you do fancy changing the wiring then instead of re arranging the pins, disconnect the plug, and use some soft wire to bridge the contacts you wish to connect. This way you can try a temporary fix without permanently rearraging the wiring.

I would check the float and any other more straigtforward reasons for it not working before changing the wiring. The chances of a previous owner messing with wiring has to be remote doesnt it.

No two GTAs are quite the same and I wouldn't put it past them to have made a subtle change..

I'll post my wiring details later this morning.

If you do fancy changing the wiring then instead of re arranging the pins, disconnect the plug, and use some soft wire to bridge the contacts you wish to connect. This way you can try a temporary fix without permanently rearraging the wiring.

I know what you mean, buy surely mine has to be wrong if 2 terminals have no connection and 2 wires have no connection? The unconnected terminals and wires look like the correspond with the tank sender. But as you say no two are the same (much like my TVR and Ginetta - it must be a plastic car thing!)

I was going to bridge, I have a handful of wires with space terminals on the ends which are ideal for temprary bridging (i did a lot of electrical fault finding with the Ginetta, the Alp is more complex though and the workings of small 24 year old computers are beyond my skill level)

To remove the boot liner to I just remove the rubber seals and lift it out or is there some secret way of attachment?

Thanks again. All very helpful

My fuel gauge doesnt work

"Join the club"


Wrong join the whole club lol apart from JohnC :lol my gauge frustrates the life out of me and there is always a gallon of petrol on board and I have used it many times often running out with 5 gallons showing and no fuel light on

si21

The chances of a previous owner messing with wiring has to be remote doesn't it.

Oh yea of little faith. Clearly as the two white sender wires are not attached to any pins on the TSU, it cannot have left the factory like that.
Look... before ripping the car apart, check the resistance across the white wires, there should be between 0.23 ohms (full) and 85 ohms (empty). If you are between those figures, then do some static checks first as per my diagram ie:- Red = permanent 12 volts, Yellow = 12 V on switch on, which will remain there for around 30 secs after switch off then cut out..... you will hear the relay click out if you are in a quiet spot. Black = earth... check, and the orange one cant be checked as it goes straight to the computer. If all the readings check out, rewire red plug to my diagram.... all the TSU`s are the same.
Of course having done all that, it does not mean there is not another fault, as I have known TSU`s to have water damage to cct boards, dry joints, and one had a blown electrolytic capacitor which had to be replaced.
Anyway, suggest you do the above and let us know what you find.

John

Previous owner was JonV so drop him a line and ask if he's messed with the plug .Pretty sure it did work for him at some point but then we went through a couple of 'black boxes ' and sender tubes .....Can't recall the exacts on this one but Jon will .

Previous owner was JonV so drop him a line and ask if he's messed with the plug .Pretty sure it did work for him at some point but then we went through a couple of 'black boxes ' and sender tubes .....Can't recall the exacts on this one but Jon will .

I had his Black Box (TSU) over here for checking... can`t remember what I found with that one but I eventually put it in my Alp, and it worked, but from what I recall, when he put it back in his Alp the fuel gauge still did not work.... perhaps the two white wires were already in the wrong place, if so the fuel gauge would never work.