achewood

So the fuel pump on my A8 went kablooey last week. The dealer has changed it at their usual enormous cost. They also say that the fuel gauge is faulty - it's saying that the tank is one-third full when it's empty and 2/3 full when it's only 1/3 full. Which means that the fuel pump is working overtime (which apparently it does when the tank is less than 1/3 full) more often than it should - which is one of the reasons why the old fuel pump broke.

Does that make sense to people? The dealer say they don't know what the problem is - whether it's a faulty gauge or faulty wiring or faulty something else, and want to do a couple of hours 'diagnosis' to work out what's up. And then, of course, charge for a replacement part and more labour.

It's been a hell of an expensive few months with this car. Anyone else had fuel gauge problems?<ul><li><a href="https://forums.audiworld.com/a8/msgs/110554.phtml">https://forums.audiworld.com/a8/msgs/110554.phtml</a</li></ul>

Always Overcharged

is the guage problem new to you?

Always Overcharged

Also there is an output test for the guage in the instrument cluster controller

KMU

A8's with erratic/incorrect fuel guage issues. As I recall the sender was the culprit. It could be a recoverable expense if this is the case. Might have seen it in service bulletin and/or recall list on Paul W's site or the service bulletin list in the Bently. Anyone else remember anything like that?

KMU

to all Audi recalls/service bulletins, but I think he had to remove the link. If there is a recall/tsb on the fuel senders, I bet you're going to have to contact Audi to get it. I'd try local stealers, but may need to call national.

achewood

that the fuel pump burned out - ie, it was being overworked because the gauge was overreading. I can recall thinking that the gauge was high once in recent weeks but that may have been nothing.

Dealer thinks that as long as we ensure that the car doesn't run too low on petrol most of the time, it shouldn't be a problem - the fuel pump won't be being overworked.

ttuling

That's an imaginative hypothesis of the dealer's, totally unsupported by anything I've seen in the service manual, at least for US model 3.7 and 4.2 petrol engines. Two things are wrong with it: an overreading gauge would be easier on a pump which works overtime "when the tank is less than 1/3 full"; and the pump is controlled by a relay so it's either on or off, but where is the accumulator to keep the car running when the pump is off?

Always Overcharged may be right about a level sensor. There are two. One may have been removed and reinstalled when changing the pump. They can be electrically tested, by measuring whether their resistance is correct for the actual fuel level.

There was a recall in the US for sticky fuel level senders in some Audi models, but high-sulfur American fuel was blamed.

Tom