Strange fuel gauge reading and fuel tank capacity.

[Sanfico]

Hi, not sure what to make of this but I have two very unusual issues with my fuel tank and fuel gauge and wondering if they are related since they both have to do with the fuel. 
Firstly I assumed my Estima is a 65litre capacity fuel tank but I have never been able to put more than 40 litres in even from empty. Second issue is that my fuel gauge doesn’t read full when I top up my tank. It only reads up to the second last bar. Could these two issues be related? Is the tank clogged up? Is it easily repairable? Thank you

[DerekHa]

Hi there Paul,

Have never owned nor worked on an Estima but from your description of your issue(s), would suggest that the fuel gauge sender unit is likely the problem. The float which is attached to the sender unit inside the tank is either trapped/sticking some how or it's damaged. The sender unit is likely combined with the intank fuel pump and filter

You should be able to check the gauge isn't at fault but you'll need to access the top of the sender unit and connect an earth to one of the terminals, this should cause the gauge to read full very quickly. Getting the connector off and also releasing the fuel lines will be difficult

Had to tackle the in tank fuel pump on my partners Citreon C1 last summer which was a nightmare! Might be best to take it into a mechanic who knows what they're doing if the sender is at fault unless you're confident tackling it yourself.

Others here will likely have more detailed advise on this.

 

[JohnGW]

Sanfico, I had this problem when I first got my Estima. Some vehicles I have owned over the years are slow fuellers, I believe the Estima is also.  To fill mine to the top I let the fuelling gun click off as usual when it senses the back pressure of a full tank, only its not yet full. Lift the fuel gun about 2" out of the fully in point, to allow the air to come out easier and slowly, half fill speed, continue to fuel. Some petrol station set their guns so finely that I just cant get a full tank but most will allow it. The gun will still click off before it hits your shoes.

Give that a try before you start thinking about pulling out tank senders etc.

[DerekHa]

2 hours ago, JohnGW said:

Sanfico, I had this problem when I first got my Estima. Some vehicles I have owned over the years are slow fuellers, I believe the Estima is also.  To fill mine to the top I let the fuelling gun click off as usual when it senses the back pressure of a full tank, only its not yet full. Lift the fuel gun about 2" out of the fully in point, to allow the air to come out easier and slowly, half fill speed, continue to fuel. Some petrol station set their guns so finely that I just cant get a full tank but most will allow it. The gun will still click off before it hits your shoes.

Give that a try before you start thinking about pulling out tank senders etc.

Have to agree with John on his suggestion about some vehicles just being slow fillers, have had a few in the past that were a pain to get fully fuelled. So well worth a try and following his advice asd he's direct experience with refueling an Estima, which I don't have. The shape of a fuel tank can cause problems with refuelling fully I know.

Thinking about this a little more now it's also possible that there's some sort of air lock forming in the tank if the venting system ins't working as designed on an oddly shaped fuel tank.

Having said that, only being able to get 40 litres into an almost emprty tank would mean there's still space for another 25 litres, thats 5 gallon in old money, and a huge amount of space not filled. That just seems unlikely to me but not impossible.

[RUToyota]

The sender would seem to most likely culprit to me.

[Sanfico]

Thanks for the advice. When I fill it’s true that the fuel gun gets triggered very easily but I already fill it to the brim by pulling the gun out and slowly filling it till no more fuel will go in. Gauge though still shows not full. 

[JohnGW]

Yep if you have tried then you have the fun job of fiddling with the sender but you would have 65ltrs no matter what the gauge says.

[DerekHa]

3 hours ago, JohnGW said:

Yep if you have tried then you have the fun job of fiddling with the sender but you would have 65ltrs no matter what the gauge says.

If you've brimmed the tank manually then there's a problem either with the gauge or the sender. My money would be on the sender as it's the most likely to fail. If you can access the top of the in-tank fuel pump, still insitu, you could potentially prove that the gauge is working correctly using an earth wire connect to the wire that feeds the gauge. If you cause a full deflection of the fuel gauge this way then it's good and the sender is suspect.

This all dependends if your ok accessing the top of the fuel pump yourself. If not then your in the hands of a decent mechanic or auto-electrician. The pump and sender are under the rear seats I believe and will be covered by a metal cover of sorts held in place with an adhesive to allow easier access.

Or do as you have been doing and live with the issue and hope things don't get worse.

One other thing crosses my mind! Could the fuel have been removed in the past and when refitting put it inside the tank out of line? If so the float could foul the side of the fuel tank and stop the correct value(s) being sent from the sender to the gauge!