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General Site Info => General Discussion => Topic started by: DuckAholic1 on January 01, 2015, 01:03:26 pm

Title: What color is ground? + Fuel gauge question
Post by: DuckAholic1 on January 01, 2015, 01:03:26 pm

87 R10 350 TBI Duel tank... Having a brain "fart"..... what color is the ground wire for the sending unit/units???? Also have a gauge problem..
1) When selector switch is on left tank, gauge reads just above 1/4 when tank is full.
2) When selector switch is on right tank, gauge reads over full.(needle all the way right)

Bottom line I need advice on where to go from here. check grounds, replace both sending units, etc??

Title: Re: What color is ground? + Fuel gauge question
Post by: Irish_Alley on January 02, 2015, 12:48:29 am

#1 i would think sending unit since the gauge does move when you switch tanks
#2 is prob because of a open circuit or poor ground. 
your grounds should be off the sending unit and attach to the filler neck
Gauge test (http://forum.73-87chevytrucks.com/smforum/index.php?topic=25339.0)
i did look here (http://forum.73-87chevytrucks.com/smforum/index.php?topic=11766.0) for your wire diagram but couldnt find it. maybe im not looking in the right spot idk
Truck manuals (http://forum.73-87chevytrucks.com/smforum/index.php?topic=25639.0)

Title: Re: What color is ground? + Fuel gauge question
Post by: DuckAholic1 on January 02, 2015, 08:50:48 am

Thank you, Irish!!

Title: Re: What color is ground? + Fuel gauge question
Post by: Drizzle on January 27, 2015, 02:06:50 am

I had the same issue and found the cause was the sending wire.  You know the wire from the selector valve is good cause the other tank shows proper level.  So it's leading to either the group or sending wire from the tank itself.  The ground wire on my truck was bolted to the frame visible between the cab and the truck bed.  Pain to get to.  I believe because your gauge shows way full it leads to the sending wire going to the selector valve from the tank in question.  Cut off old wire and splice in new wire temporarily to give it a try.

Title: Re: What color is ground? + Fuel gauge question
Post by: DnStClr on January 30, 2015, 06:44:12 pm

Here's a pic of a pump I replaced. The ground wire was black. It was attached to the frame like Drizzle said. It's the wire with the yellow terminal .
(http://i227.photobucket.com/albums/dd22/Dnstclr/VariousPicsfromsummer2009040.jpg) (http://s227.photobucket.com/user/Dnstclr/media/VariousPicsfromsummer2009040.jpg.html)

on edit- that's a pretty lousy picture isn't it?