Fuel sensor broken?

[joris_andriesse 8]

Hi,

My fuel gauge wasn't reacting anymore, and after quite a search I ended up in taking the fuel sensor out of the tank. Nothing to see there, two wires inside (middele and spring like on the outside) bot not broken and still connectend, further nothing special in my opinion. But then, when I did hold the sensor vertical the floater dropped all the way down (like the tank was empty) and on that the gauge reacted and the warning light (low on fuel) started to burn. So I start to believe that the sensor is broken down.

Questions:

- Can I somehow measure that

- Can it be repared

- If not to be repared, are there universal aftermarket sensors for replacement? Because I already found out that original fuel sensors aren't available anymore.

 

Cheers,

 

[Gohn 68]

there are Jaeger and Veglia fuel level senders, do you know what yours is ?

the Veglia ones are easier to repair as they can be dismantled, so fingers crossed

I had trouble with my fuel guage also, but it ended up being a totally different problem so I've not pulled a sender unit apart

the link is:

 

 

it sounds like yours is sticking instead of sliding up/down smooth so a cleanout should fix it

 

 

[joris_andriesse 8]

I guess I have a Veglia, because taking it apart was easy. Just taking away some locking washer at the bottom and then I could taken away the alumnium housing. The floating part could easily be moved up and down, but even in it woud stick in the middle I woud expect a signal to the gauge. 

 

Perhaps the gauge is not ok anymore, I don't know, but since that one was reacting when the floater dropped all the was down, I was thinking it is the sensor/sender.

 

 

[Gohn 68]

its good you have the veglia sender unit

maximum resistance is at empty with the float down the bottom

so if you short the wires the needle should shoot to full on the gauge

as you say, it still should be giving a signal half full though  ?

 

if you're not able to fix it you can still buy used ones or go to a breakers yard

 

 

 

 

[joris_andriesse 8]

10 minutes ago, Gohn said:

so if you short the wires the needle should shoot to full on the gauge

 

if you're not able to fix it you can still buy used ones or go to a breakers yard

 

 

 

 

I did read your topic, thanks for the tip, looks the same as I'm facing (although, no lizzards here :p ). Will try what will happen with shorting the wires, should I short white and blue or blue and earth, not completely clear to me.
I btw also measure 5-6 v on the white wire, that shouldn't be as I understand from your topic? And where did you get the cluster/gauge thingy from?

 

[Gohn 68]

4 hours ago, joris_andriesse said:

where did you get the cluster/gauge thingy from?

I had an old used one sitting in a box

a broken coil/wire seems the most likely cause of the no signal so I'd def check the sender unit properly before looking at the dash/gauge

dont forget to turn your ignition key on then

get the female loom plug at the sender unit, cross a small wire from the blue(power) to the green/yello(earth)

your fuel guage needle should swing up to FULL tank

if not try crossing the wire to the other combinations

if you still cant get the gauge needle to move at all, it probably IS the dash gauge and NOT the sender unit

 

also, I'd forgotten the low fuel lamp has its own wire so its not really indicating much just because it comes on

 

 

 

 

[joris_andriesse 8]

I did short the plug, green/yellow and blue and indeed the gauge went to full tank and since it also reacts on when I take the sensor/sender out (gauge goes to empty tank with burning warning light), I would think that indeed the sensor/sender is broken.

Anyone any idea whether I can replace it wit such a one (sorry, website in Dutch): https://www.shop.exalto.com/scheepsbouw/instrumenten/boord-instrumenten/sensoren/vdo-buisvlotter-brandstof-90-4-ohm-150-mm-a2c1749300001

What Ohm resistance do I need, there is also a 240-3 ohm version. The one in the link is 90-4

 

Edited November 30, 2021 by joris_andriesse

[joris_andriesse 8]

And one more question/doubt.
The VDO one has a two pin connector (power-signal), while the original one has a three pin connector (power-signal-earth). Is it going to work with a two pin connector, how does that work?

[Tom Fenton 1,542]

The original is not power/signal/earth. There are 2 contacts for the variable resistance to the gauge and one which switches to earth for the low fuel light,

 

Can't help but think you are making this difficult, just find a working second hand sender and fit it would be an easy job.

[joris_andriesse 8]

4 hours ago, Tom Fenton said:

Can't help but think you are making this difficult, just find a working second hand sender and fit it would be an easy job.

I know that sounds reasonable, but also a second hand is like 30 year old. I thought that if this would be a good option, I could beter go for new

[mmt 15]

Hijack on: 

 

how would you best test if the low fuel light swich works ? 
 

thanks :-) 

[welshpug 1,657]

connect your multimeter between the appropriate pair of pins

[mmt 15]

Thanks :-) 

is there a more descriptive dummy version?

[welshpug 1,657]

find plug, poke it with multimeter.

[soundguy 13]

Try Valeo 347355 - thought these were about £35 last summer but now they're either out of stock or £70-80.

[joris_andriesse 8]

Today I received an other (used) sender, that didn't fix the problem

What I tried/found out:

- Connection blue and green, gauge gives full tank

- Connecting white and green, gauge warning light starts to burn

- Connectiong plug and sender, outside of the tank, gauge moves to "tank empty" and warning light starts to burn

- Placing the sender back in the tank, gauge drops in the left corner, like no contact.

I'm out of options, any of you have any idea where the problem might be?

 

[welshpug 1,657]

sounds like broken/damaged wire or dirty terminals, you say it worked when connected outside the tank?

[joris_andriesse 8]

2 hours ago, welshpug said:

sounds like broken/damaged wire or dirty terminals, 

But why is it than reacting om min/max full en nothing more? I'm trying to understand

 

2 hours ago, welshpug said:

 you say it worked when connected outside the tank?

Yes, when take it out of the tank, while connected to the cable, the sender unit drains the petrol and when the floater (inside the sender) hits the bottom of the sender, my gauge moves to empty and the warning light starts to burn.

[Gohn 68]

that's weird, doesn't make sense

what mei said was what I thought too

but connecting the sender unit outside the tank you are still using the same plugs and loom wires for a signal

so

why would you get a signal using the same sender and loom from outside the tank but cant get one with the sender in ?

from your reports it cant be the sender (because the replacement did the same thing as the original)

but also it cant be the wiring loom because you get a clear FULL signal or LOW FUEL warning lamp with the sender manually connected outside tank

and that also suggests it can't be an earth problem

 

do something illogical and check the wires look ok anyway

then check the rear earth cluster at the Left Rear brake light, make sure its clean etc

 

then I'd try getting a Half Full signal on the dash, its the only thing you cant get

with the sender out of the tank, take it out and push the float about see if you can get the needle to swing half full

 

good luck

 

 

[joris_andriesse 8]

Today a try on measuring restistance on the wiring and all seems fine ('no' resistance between sender plug and dash plug). So all there is left, is finding out which one of those (sender/dash) is causing this issue.

[Gohn 68]

good on ya joris,

you'll find it

[joris_andriesse 8]

On 12/12/2021 at 10:37 AM, Gohn said:

good on ya joris,

you'll find it

 

And also a change of the dash/gauges unit didn't do the trick.
Then I was lucky to have a smart guy passing by and after some measuring he gave the suggestion to swap, on the sender plug, wire 1 and wire 3. And the result is amazing :p
Many thanks @wicked for the tip!

 

 

 

How it came?

My wiring was like this (big wonder fuel level still worked, warning light for sure didn't work anymore). Order of colours kept the same, but somehow I managed to flip the plug

 

At all, thanks for your suggestions/help, much appreciated!
 

[welshpug 1,657]

aha!   so it was broken wiring, in a way!