On Monday, my car was in for new tyres all round.

The fitters had problems getting the drivers front and rear wheels off. It's the first time the wheels have been off since I've had the car and it had been sat for roughly 4 years before I got my hands on it so I'm not surprised it was all a bit seized up.

Anyway long story short, it ended up needing a new front hub fitted too.

When I got the car back, I noticed it seemed to be using a lot of fuel. The gauge was dropping pretty quickly.

I checked out the MPG and it seemed about the same as before, 24.7 Avg MPG. I'm only doing shortish trips at the moment about 20 / 30 miles max with a combination of motorway and urban. The Inst MPG seems about right throughout the drive.

Along with the fuel gauge dropping pretty fast is the estimated range dropping quickly too.

For example on a 18 mile trip with 70% motorway and the rest urban my gauge dropped about 1/8 of a tank.

Here's the strange bit, as I came off the motorway and started the urban driving the gauge seemed to recover a little going back up. Not much but noticeable.

I decided to see what would happen if I just sat in a car park and let it idle for a few minutes. The gauge kept dropping fairly quickly and I went from an estimated 175 mile range to an estimated 172 mile range within the space of 3 minutes sat with the engine just idling - no revving.

My instant reaction is to think I have a fuel line leak somewhere? Is this about right?

These aren't my usual mechanics, just went there for tyres.

Is it possible these guys could have damaged a fuel line when putting a new hub on the driver front or when lifting the car?

Typically, this all becomes apparent on a Friday when I really need to have the car all weekend and my mechanic is booked up.

I haven't filled the tank up again yet to see if it actually is low on fuel or if it's just the gauge playing tricks. I also haven't had a chance to have it sat idling in my drive whilst looking for leaks underneath.

It doesn't seem to be losing fuel when it's sat up overnight.

If it is a fuel line leak (and I can find it) is it possible to patch it up for a few days or is that likely to cause more problems?

Any suggestions would be greatly appreciated until I can get my mechanic on board sometime next week.

 

Can you smell fuel?

It is possible to damage fuel lines if the car is not jacked up properly.

On my car the fuel line runs up the left side under the sill and if a lift pad contacts under the sill in the wrong place it would/ could damage the line.

If that happened I am sure you would smell gasoline.

 

Faulty sender not uncommon on this Jag due to corrosion on contacts.

I suggest that you just keep it topped up for now, the problem might go away,

like mine did.

 

Agreed if ANY fuel was leaking out, the smell would be almost overwhelming in a closed up garage. Am not sure just how readings are obtained on this car, but a float is how the fuel level is measured in any of the fuel tanks i've been into. They give readings that are not always that accurate, but a close proximity of the level at the time. So everything is an approximate reading, and pretty close to what's in the tank. The other stuff such as milage at the present moment MAY also be involved.

 

Well, that sounds right. You're burning fuel and doing no miles so the average mpg is lower and thus the predicted range is also.

 

I've not smelt any fuel as yet. The car isn't garaged and being in the UK, I'm getting in and out of the right side away from the fuel lines.

My journeys are pretty predictable, in and out of town to work - 70% motorway, 30% urban. According to the gauge, I've used as much fuel in the last two days driving as I would normally use in about 5 days doing the same journeys.

I'm going to fill up on the way home. The tank takes 85ltrs - is that correct?.

Fuel gauge is currently registering about 1/4 of a tank so if it's correct I would expect it to take somewhere in the region of 60ltrs to fill?

I've read a faulty sender mostly shows with a low fuel light coming on soon after filling which I've never had.

If it is the sender being erratic, I should actually have more fuel than the gauge says - over half a tank by my reckoning comparing my usual usage with the journeys I've done. We'll see when I fill up.

Once I get home, I'll let it idle and see if I can smell any fuel around the car. Fingers crossed I can't.

The fuel gauge has been absolutely perfect, giving expected and reliable readings right up until I got it back from having the tyres/hub done.

 

Just back to the car. Turned on the ignition and the fuel gauge is back up to 1/2 tank and the predicted miles is back up to 221.

Went to fill out up. It took just over 41 ltrs so about half a tank.

And, lastly no smell of fuel.

Seems like it is the fuel sender playing up.

I'll keep the car topped up and see if it corrects itself over time if not I'll need to look into getting there sender replaced but I read somewhere that's not a cheap job?

 

It shouldn't be expensive. The sender is a plastic pot with arm and a bit of foam

on the end which clips onto the side of the fuel pump.