Problem with fuel guage

[Paul]

Hello,
I own a 95 1600i. I am having problem with fuel guage and wondered if you could help? When i turn ignition the fuel guage reads ok but when i start the engine the needle drops right off the gauge!! Any ideas what may be the problem?
Really appreciate any advice!!

_________________
All the best
Paul

[phade]

Hiya Paul,

Does the fuel gauge remain off the bottom of the scale after you have started the engine? Also does the alternator light or the brake warning light remain on or flicker after you have started the engine?

It sounds like any of the following is dropping the voltage to the fuel gauge downwards:-

- ECU relay
- Fuel pump relay
- Alternator

An easy way to check the alternator is to measure the battery voltage before and after you have started the engine. The voltage across the battery when the engine is running should be between (about) 13.5V to 14.5V.

It may also be a good idea to check the alternator's belt deflection. The deflection (at the middle of the alternator belt) should be the following with light thumb pressure:-

- Used belt: 11mm to 14mm
- New belt: 9mm to 11mm

If the alternator was proved to be ok, then the ECU and fuel pump relays should be removed, taken apart and checked for dried solder joints.

Apart from that I cannot suggest a lot else at the moment since the wiring diagram doesn't seem to point at anything else.

Good luck with your fuel gauge,

Phil

[Paul]

Hi
Thanks for that, i will do some testing and let you know how i got on!
cheers
paul

_________________
All the best
Paul

[Paul]

Hi
tested voltage and it was ok, turned out to be sender unit in tank. Now fuel gauge reads correct level but holds the reading when ignition turned off. Is this normal? All my other vw`s gauges read level only when ignition on!
Thanks for your advice!
paul

_________________
All the best
Paul

[phade]

Hiya Paul,

Yes this is perfectly normal, my year 2000 mexican beetle does exactly the same, where as my 1973 1300 does not.

Cheers,

Phil