Fuel gauge erratic readings
Thread Starter
Racer
Joined: Aug 2003
Posts: 318
Likes: 0
From: Netherlands
Fuel gauge erratic readings
Ok, call me slow, but I just figured out, after owning the car for a year, that something is wrong with the fuel gauge or some sensor it depends upon. It never gets to full, stays somewhere between full and 3/4 full. Then the needle drops rather quickly (after ca 400 km) all the way down below even the orange marking for reservefuel. It stays there for another 100 km until something in the machine figures out it is actually now on reservefuel, and causes the needle to pop back to it's correct position, just above the orange marker, and the marker light and warning light are lit. Weird..
Any ideas ?
Piet
87S4
Any ideas ?
Piet
87S4
Rennlist Member
Joined: Dec 2002
Posts: 5,283
Likes: 52
From: Australia
The gauge is driven by a float that slides up/down a wire rod, with contacts sliding down two runs of fine resistance wire ~ 80ohms empty, near zero full. The wire gets coated with fuel deposits/shellac etc, and contact becomes unreliable. The float can also twist a bit and cease pressing its wipers on the wires. You will probably need to pull the unit out and clean it. Do a search - I have posted details before on this.
jp 83 Euro S AT 48k
jp 83 Euro S AT 48k
Rennlist Member
Joined: Jan 2004
Posts: 12,620
Likes: 8
From: Boulder Creek, CA
Rennlist Member
Joined: Dec 2002
Posts: 5,283
Likes: 52
From: Australia
eXCELLENT PIC! On my car the little V shaped slider had one wire on the open side , instead of on the pointy side, so contact was spasmodic. Both need to have wire on pointy side to ensure contact. And boy was it dirty!
jp 83 Euro S AT 48k.
jp 83 Euro S AT 48k.
Thread Starter
Racer
Joined: Aug 2003
Posts: 318
Likes: 0
From: Netherlands
Gentlemen,
Muchas gracias. Great pics man, really helps. I do remember not so long ago to try and unscrew the ring that holds this unit, in connection with a suspected clogged fuel line or something, I also have a slight idle problem; but anyway, that ring can get really stuck. Do I need some special tool for this or just apply brute force ?
Piet
87S4
Muchas gracias. Great pics man, really helps. I do remember not so long ago to try and unscrew the ring that holds this unit, in connection with a suspected clogged fuel line or something, I also have a slight idle problem; but anyway, that ring can get really stuck. Do I need some special tool for this or just apply brute force ?
Piet
87S4
Rennlist Member
Joined: Jun 2004
Posts: 347
Likes: 0
From: Knoxville, Tn
Sharkskin: Great write-up. I've had my shark for a few months and the gauge won't go below 3/4 tank. (Gas set in the tank for almost 10 years, i presume it was 3/4 full). When I get home, the first thing I'm going to do is clean that sender up.
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