[Roadsters] Fuel indication issues

Mon May 11 16:04:53 MDT 2020

This is very helpful, thanks.

Once point I note is it seems the range of the 311 sender unit 
resistance is backwards to the 310 -- greatest when tank is empty (47 
ohms) and least when full (approaching zero).

- Bob

On 5/11/2020 4:42 PM, Pat Horne via Datsun-roadsters wrote:
> Thanks, Mike. I’m not sure how this circuit compares to the 311 but 
> I’ll check. One difference I see is that the 311s have a voltage 
> regulator for the instruments. I’ll have to check on the ground for 
> the gauge. If there is one, that could cause this problem if it is bad.
>
> Peace,
> Pat
>
> Pat Horne
> We support Habitat for Humanity
>
>
> On May 11, 2020, at 3:37 PM, mikelyons at aol.com wrote:
>
> 
> I have the Nissan Service Manual for the SPL 310. The attached PDF is 
> a copy of the information concerning trouble shooting the fuel gauge 
> and a wiring diagram.
>
> I hope it can be of help.
>
> Mike Lyons
> Vancouver, WA
> 1967 SPL 311 with 135 HP 2000
> 1967 1/2 SPL 311
> 1983 280ZX Turbo
>
>
>
> -----Original Message-----
> From: RWM via Datsun-roadsters <datsun-roadsters at autox.team.net>
> To: Pat Horne <patintexas at icloud.com>
> Cc: Datsun List <datsun-roadsters at autox.team.net>
> Sent: Sat, May 9, 2020 1:57 pm
> Subject: Re: [Roadsters] Fuel indication issues
>
> Pat,
>
> The black wire is zero (ground).
>
> Guess I'll try to work my fingers up behind the gauge and check for 
> continuity.
>
> Thanks.
>
> - Bob
>
>
>
> > On May 9, 2020, at 16:53, Pat Horne <patintexas at icloud.com 
> <mailto:patintexas at icloud.com>> wrote:
> >
> > Bob,
> > That sounds a bit off. The 7.6v on the yellow wire to ground is 
> fine, but the black wire should be zero.
> >
> > When you ground the yellow wire to the body, the gauge should go to 
> max. Sounds like you have a bad fuel gauge. Just to be sure you can 
> try grounding the terminal on the gauge that the yellow wire goes to.
> >
> > Peace,
> > Pat
> >
> > Pat Horne
> > We support Habitat for Humanity
> >
> >
> >> On May 9, 2020, at 3:09 PM, RWM <RWM at rwmann.com 
> <mailto:RWM at rwmann.com>> wrote:
> >>
> >
> > Pat,
> >
> > With ignition switch in running position
> >
> > Yellow wire to chassis is 7.6 volts, same as to black wire
> >
> > Yellow wire to ground, no gauge deflection
> >
> > Thanks
> >
> > - Bob
> >
> >
> >> On May 9, 2020, at 13:19, Pat Horne <patintexas at icloud.com 
> <mailto:patintexas at icloud.com>> wrote:
> >>
> >> Hook everything back up except the sender. Turn on the key & 
> measure for voltage @ the sender wires to ground. One should show 
> voltage & the other should be grounded. (Not home now to get colors) 
> ground the one with voltage. If the gauge still sits on empty you have 
> a bad gauge. If there is no voltage it could be a bad connection or a 
> bad gauge. Let me know what y’all find & I’ll walk you through more 
> diagnostics.
> >>
> >> Peace,
> >> Pat
> >>
> >>
> >> Pat Horne
> >> We support Habitat for Humanity
> >>
> >>
> >>>>> On May 9, 2020, at 11:02 AM, RWM via Datsun-roadsters 
> <datsun-roadsters at autox.team.net 
> <mailto:datsun-roadsters at autox.team.net>> wrote:
> >>>
> >>
> >> This has been discussed before, but here are the indications:
> >>
> >> Fuel gauge does not budge off empty
> >>
> >> Fuel sender resistance shows 34 ohms as installed, with tank less 
> than half full
> >>
> >> Fuel sender resistance when removed varies fairly linearly from 47 
> ohms (bottom) to near zero ohms (near top), then open circuit when the 
> arm forces the wiper off the rheostat windings
> >>
> >> Fuel harness is delivering 7.6 volts, measured with the yellow and 
> black connectors removed
> >>
> >> Shorting the fuel harness to itself (yellow to black) does not 
> change the fuel gauge indication
> >>
> >> Ammeter works, temperature gauge works
> >>
> >> Ideas? Dash harness connector?
> >>
> >> Thanks.
> >>
> >> - Bob Mann, '68 2000 Solex
> >>
> >>
> >> ________________________________________
> >>
> >> datsun-roadsters at autox.team.net 
> <mailto:datsun-roadsters at autox.team.net>
> >>
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> >>
> >>
> >
>
> ________________________________________
>
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>
> <SPL310 Fuel Gage.pdf>
>
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>
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