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Fuel Gauge Bounce

Posted: Sun Sep 15, 2019 4:40 pm
by silverboydreamer
Hi, does anyone have any suggestions to overcome the bounce of the fuel Gauge on my 63 T6 with the oblong tank and filler under the bonnet?, as the fuel sloshes around the tank when the car is in motion the gauge dances around quite a lot. Is there a fix for this or do I just have to live with it.

Re: Fuel Gauge Bounce

Posted: Sun Sep 15, 2019 6:05 pm
by mycar
PRS sell a fuel needle damper.

https://www.prs356.co.uk/porsche-356-pa ... e-jumping/

It can be fitted to the fuel tank sender or to the fuel gauge itself.

If you're feeling handy you can DIY, it's basically a 5 volt, 4 ohm 0.1 F capacitor.

Image

Works well in smoothing things out... your fuel needle becomes less pogo and more plié.

Re: Fuel Gauge Bounce

Posted: Sun Sep 15, 2019 8:36 pm
by Hugo 356
Average the bounce to work out how much fuel you have left - you've got the reserve if you get it wrong. Just don't drive into the car in front, hypnotised by the swing...

Re: Fuel Gauge Bounce

Posted: Mon Sep 16, 2019 9:19 am
by Hendrik Moulds
Just be grateful you have a gauge, some of us have to make do without! :wink:

Re: Fuel Gauge Bounce

Posted: Mon Sep 16, 2019 9:57 am
by mycar
Here's a fuel gauge for you Hendrik. :laughing6:

Image

Re: Fuel Gauge Bounce

Posted: Mon Sep 16, 2019 11:59 am
by silverboydreamer
Thanks for info, I will try the damper capacitor route, I know you early car guys might think what am I complaining about because I at least have a Gauge, it’s just irritating when the needle jumps from three quarters full to zero then to half.

Re: Fuel Gauge Bounce

Posted: Mon Sep 16, 2019 2:26 pm
by soulsonicboy
I think I have none of those dampers that I never used on my 912 as it needed a new sender unit in the end. PM me if you want it and I’ll dig it out.
Cheers
Ben

Re: Fuel Gauge Bounce

Posted: Mon Sep 16, 2019 3:24 pm
by neilbardsley
soulsonicboy wrote:I think I have none of those dampers that I never used on my 912 as it needed a new sender unit in the end. PM me if you want it and I’ll dig it out.
Cheers
Ben
I suspect Hendrik's car maybe 6v?

PS I filled my car up to almost spilling point and the gauge said I could get another 1/8 in

Re: Fuel Gauge Bounce

Posted: Mon Sep 16, 2019 4:42 pm
by Hendrik Moulds
neilbardsley wrote:
soulsonicboy wrote:I think I have none of those dampers that I never used on my 912 as it needed a new sender unit in the end. PM me if you want it and I’ll dig it out.
Cheers
Ben
I suspect Hendrik's car maybe 6v?

PS I filled my car up to almost spilling point and the gauge said I could get another 1/8 in
Is there another voltage? :?

Re: Fuel Gauge Bounce

Posted: Fri Sep 20, 2019 11:30 am
by POR68
I fitted a 0.1F cap across the sender terminals about 3 years ago. Works well.

Re: Fuel Gauge Bounce- RESULT

Posted: Sat Sep 21, 2019 9:37 am
by silverboydreamer
Hi further to my post about the fuel Gauge bounce, I have fitted a capacitor ( supplied by a member) to the fuel tank contacts and it has cut down the fluctuation a noticeable amount.
Thanks to all who contributed to the discussion for a successful conclusion.

Re: Fuel Gauge Bounce

Posted: Mon Sep 30, 2019 8:53 pm
by 356Monkey
Can I check, are you literally wiring the capacitor across the 2 terminals on the sender? I'd like to fit one on my car but wanted to check - or does it wire in series through on of the sender wires?

Re: Fuel Gauge Bounce

Posted: Tue Oct 01, 2019 9:30 am
by Ashley James
My chum who is an electronics engineer suggested that it might need 10mF to damp it completely. It would be across the sender or the meter.

Re: Fuel Gauge Bounce

Posted: Tue Oct 01, 2019 2:00 pm
by mycar
356Monkey wrote:Can I check, are you literally wiring the capacitor across the 2 terminals on the sender? I'd like to fit one on my car but wanted to check - or does it wire in series through on of the sender wires?
Yes, connected between the 2 terminals.

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Re: Fuel Gauge Bounce

Posted: Tue Oct 08, 2019 9:27 pm
by 356Monkey
Many thanks for the pic - makes perfect sense now

thanks