Subject: [TR] TR3 fuel level sending unit and gauge issue

From: "CFM-TR" <[email-masked]>
Date: Sun, 03 Nov 2013 15:43:35 -0500

How do you test a fuel gauge and/or the sending unit out of the car?   I am
not getting any readings (no fuel level on gauge).  

wiring: 

a) switched green to 'B' side of gauge

b) 'T' side - green/black into harness and out to insulated side of sending
unit

c) black from other side of sending unit to ground at tank strap

d) added ground from gauge mount to ground point on center dash (which is
also directly connected to frame)

about 10 gallons of gas in tank

Power on - no reading.

I have a test lamp with alligator clips on both sides (indicated as TL
below)

I have a jumper from gauge mount direct to frame ground (FG) as gauge is
hanging loose and not grounded through dash,etc

tests:

1) 'B' side  TL  to  gauge mount  tests ok  so there is juice to the gauge.

2) Ran a jumper from 'T' side of gauge to the insulated side of the sending
unit (SU) and another from the ground side of the SU to the same FG as
above.  still no fuel level on gauge.

3) Jumped between two terminals on sending unit - still no fuel level on
gauge

4) Changed gauge mount jumper from FG to SU ground; 'B' TL to gauge mount
tests ok so the sending unit is grounded. 

5) 'B' side TL  to SU-Insulated - no TL; added jumper between 2 SU terminals
- TL ok.  Is Sending Unit functional?

I don't know what to do next.

How do I tell if it is the sending unit or the gauge?  or could it be both?

Carl

1960 TR3A - TS81802LO

http://mysite.verizon.net/cfmtr3a/ 

Tampa, Florida

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Archive: http://www.team.net/archive

---

From: Dave Massey <[email-masked]>
Date: Sun, 3 Nov 2013 21:34:58 -0500 (EST)

A TR3 fuel gauge should read full with the green/black wire disconnected and
it should read empty with the green/black wire connected directly to ground.
If the gauge doesn't respond like this I would suspect the gauge.  You can
test the sender directly with an ohm meter.  Full should be 500 ohms or more
and empty should be 50 ohms or less.

Dave Massey

-----Original Message-----
From: CFM-TR <[email-masked]>
To: ''Triumphs'' <[email-masked]>
Sent: Sun, Nov 3, 2013 2:53 pm
Subject: [TR] TR3 fuel level sending unit and gauge issue

wiring:

Power on - no reading.

tests:

Carl

1960 TR3A - TS81802LO

Tampa, Florida

Archive: http://www.team.net/archive
http://autox.team.net/mailman/options/triumphs/[email-masked]