[Roadsters] Fuel indication issues

[Pat Horne]

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> 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> 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> 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> 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
>> 
>> 
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>> 
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> 

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<SPL310 Fuel Gage.pdf>
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