Technical Fuel guage stopped working? WTF!

[h2ypr]

Took the car out for its first proper drive to the car wash and it drove really well. Slight miss i think around 2000-3000rpm after certain gear changes, but on the whole drove well and pulled well. Handling is well, not what im used to, but it does grip the road well (corner i can progressive accelerate through in the the coupe to 65 mph the cinq done at 50 which i thought was good.)

But, on the way home i was canning it (50mph) up a hill and noticed that the fuel gauge was reading 0.

Now i had just put in 5 litres yesterday via a petrol can and the trip was only 4 miles. Its not just reading 0, its like there is no signal getting to it....

Stripped away the dash and everything else is working fine and the connectors are on properly. One thing i did test, putting the fuel gauge round past the full mark and then turning on the ignition would force the needle to empty again whereas without the ignition it wouldnt fall at all, so obviously the signal the sender is sending out, is that its 0.

Any ideas?

Ross

p.s. wee pic of it getting cleaned !

 

[rallycinq]

Time to lift the plate where the rear seat was and check the connections under there.

Cheers

D

 

[h2ypr]

Time to lift the plate where the rear seat was and check the connections under there.

Cheers

D

Spot on David! Thats the kinda advice i was looking for. On the coupe the connections are in the boot, at the top of the fuel pump.

Ross

 

[Brooky]

is that where the fuel pump/sender is then...under the plate in the boot/rear seats??

 

[cheeqic_nto]

Under the rear seat is a plate, lift the plate and you will find an assortment of hoses and 2 electrical connector blocks. With the ignition switched on unplug each of the connectors, one will make the fuel pump stop, plug this one back on as it's the fuel pump power. With a meter check the 2 wires on the other plug, this being the sender wiring, 1 of the wires should show 12volts, this is the feed from the gauge to the sender, if this wire is touched to the body the gauge should show full. If it doesn't it would suggest a gauge or wiring problem, if it does then it's the sender. Hope this helps.

 

[ness83]

Hi.
I bought a cinquecento last week and the guy said after he had the fuel pump changed they knocked the wire and now the gauge isnt working. Although he hadnt previously mentioned this when we agreed to buy, we carried on with the sale anyway thinking it would be simple, I've had a look but I dont reckon I understand enough to do it.
I sounds like it is simple enough from the last post, but I dont want to make it worse, should I just take it to a garage? Is it gonna cost me loads? This is my first car and its already cost me a fortune (car also had a slow puncture and no spare...)
Help!!

 

[rallycinq]

Ok, welcome, now relax.

Here are the simple instructions for checking the fuel gauge.

Lift up rear seat, dind diamond shaped panel held down with four nuts.

Remove nuts (from car, no need for surgery) Lift up panel, this may need a flat blade to help prise it up, the sealant sometimes is a bit sticky.

With the panel off you will now be looking at the tank. The gauge connector is right in the middle of a ring of small bolts. The connector is usually black and is angled towards the rear of the car. Examine carefully, no naked lights please, and remove the plug from the sender. Look carefully into the plug and make sure the connector strips are in place.

What sometimes happens, is that when removing the plug the strips get pushed away from their correct position so that they don't make the connection when refitted.

Refit and check.

Lesson two will follow if no change.

Cheers

D

 

[ness83]

Thanks so much for your reply. I took the plug off and checked the connections, all ok. The middle connector was slightly corroded, so I scraped off corosion, plugged back in, still no joy.

I may need plan B if you would be so kind!!!

Vanessa

 

[rallycinq]

Plan B, as requested.

In the plug are three wires.

The black one is the earth. Ignore it for now, thats plan E or F.

The light blue and yellow wire is the gauge feed. Take a short length of wire and carefully insert one end into the plug and hold the other end against one of the bolts that hold the diamond shaped cover in place. This should cause the gauge to rise.

Report back.

If you do the same with the middle wire, the light blue and red, then the warning light should come on.

Cheers

D

 

[ness83]

Hi there,

I have this morning carried out plan B and the gauge shot up to full.
So, does this mean its a sender problem? Whats next?

Thanks,

Vanessa

 

[rallycinq]

Yup sounds like a sender prob. Back in a min

Cheers

D

 

[rallycinq]

Sorry, too dark to find the spare tank in the garden.

Maybe tomorrow.

Cheers

D

 

[ness83]

Ok, no worries, the cars not going anywhere, still not got those tyres sorted!!!
Appreciate your help so far,


vanessa

 

[rallycinq]

Late as usual, but back, sorry.

Looking at the top of the tank unit where the connector goes, you will see a circle of plastic about 3 inches in diameter. this is the sender unit. There are two 'U' shaped lugs on the top. Insert a pair of needle nose pliers across the lugs and turn anti clokwise about 15 degrees. This will allow you to remove the sender unit.

However, the unit is not a servicable item, so pm me if you decide you want another one.

Cheers

D