V8 Vantage - Fuel gauge problem

[l8lue]

The fuel gauge on my 2006 4.3 Vantage has always been slow to register re-fuelling (it could take 10 mins to show "full") but I assumed this was some form of damping to prevent oscillating level indications.

Last week, with half a tank of fuel in the car, the gauge needle dropped progressively over 20 minutes to show "empty" and the fuel computer warned ---- miles.

The next time the car was started, the reading was normal. The time after that "empty". The gauge now shows only about one quarter tank when full and at random drops slowly back to "empty"

I think that there are 3 probable causes
1) Faulty sender unit in fuel tank
2) Faulty gauge
3) An electrical glitch (ie computer problem) - Note the car runs perfectly well with the fuel computer on ---- miles!

Before I attack the wrong part of the car, does anyone have any experience or knowledge of this problem?

Thanks

[drofnavi]

Check the sender unit leads for corroded terminals or a bad earth, it might be a simple no or low cost fix.

[l8lue]

Thanks - I'll have a look tomorrow. I have a pit in the garage so can look from underneath, or is there an easy way in from the top?

[divetheworld]

l8lue said:

Thanks - I'll have a look tomorrow. I have a pit in the garage so can look from underneath, or is there an easy way in from the top?

http://www.puwer.co.uk/uploads/V8%20Vantage%20fuel%20sender.pdf

Edited by divetheworld on Monday 6th May 18:02

[adsl3897]

I have a similar issue with my fuel gauge. On mine it seems to only happen on half tank or less, it will just randomly drop to 0 reading, then sometimes go back up, or down...just random. Will be interested to hear of the outcome...

[divetheworld]

l8lue said:

Thanks - I'll have a look tomorrow. I have a pit in the garage so can look from underneath, or is there an easy way in from the top?

Under the carpet in the boot.
The sender is under an inspection cover.

[l8lue]

Thanks for the advice. It is really helpful.

I will report back, when successful.

[l8lue]

Problem! I pulled the car out to sort the tank connections in the sunshine. However when it started, the gauge read correctly (2/3 full). Longish journey, short journeys and all is well.

As the Vantage has cured itself, I cannot investigate the fault, unless it returns. Good news for me, but I suspect it may be temporary.

I will re-post when there is something to report.

[Little Donkey]

I thought I had a similar problem in my V12V when the fuel gauge needle was dropping at about the same rate that the rev counter was rising

[drofnavi]

It still sounds like a dirty electrical terminal connection.

[yeti]

drofnavi said:

It still sounds like a dirty electrical terminal connection.

What he said. If you can find it, give it a clean and re-seat it. Nothing to lose!!

[Cerbieherts]

You can check the sender output with a multimeter, across the red/white and black and white wires (next to each other in the four-way plug) It should read 204 ohms with an empty tank and 10 ohms with a completely full tank. They also seem to suffer with integral resistance build-up in that plug, so well worth giving it a spray with some contact cleaner.

[Cerbieherts]

Underneath the car, clipped to the rear subframe on the passenger side

[telum01]

This just happened to me this past Saturday - pretty terrifying to watch the fuel gauge slide to zero over the course of half an hour while I'm in the middle of nowhere! I'll be checking all my wires and connections whenever I get the time in the next few days... I really hope it's a simple fix and it isn't the sending unit.

[SteveT491]

I’m having a problem with the fuel gauge on my V8 Vantage. The gauge drops to indicate zero after only about 75 miles from a fill up. It was fine when I bought the car about a year ago, but it’s progressively got worse this year. Has anybody figured out how to fix this? I read a note about checking the connections on the sending unit and it’s supposed to be under the trunk/boot carpet and under an inspection cover… Mine doesn’t seem to have anything under the carpet so I’m wondering if I’m looking in the right place? Any personal experience with this will be appreciated!

[Calinours]

SteveT491 said:

I’m having a problem with the fuel gauge on my V8 Vantage. The gauge drops to indicate zero after only about 75 miles from a fill up. It was fine when I bought the car about a year ago, but it’s progressively got worse this year. Has anybody figured out how to fix this? I read a note about checking the connections on the sending unit and it’s supposed to be under the trunk/boot carpet and under an inspection cover… Mine doesn’t seem to have anything under the carpet so I’m wondering if I’m looking in the right place? Any personal experience with this will be appreciated!

1st prize this month for ancient thread resurrection

The advice given to the others above is sound, this seems most likely to be an aging level sensor/sender or an electrical connection developing high resistance through the usual aging and corrosion. Start with the senders terminals and the cleaning spray. If no result, move on to checking sender function using a multi-tester when you see the gauge not working properly.