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73-87 Chevy _ GMC Trucks => Interior & Equipment => Instrumentation => Topic started by: theaddictedchef on November 04, 2014, 04:28:30 pm

Title: Fuel Tank Sending Unit Wiring
Post by: theaddictedchef on November 04, 2014, 04:28:30 pm

Okay.....so here's what I did.
 Ordered:  crate engine, two fuel tanks, two sending units, harmonic balancer, speedo cable, engine and tranny mounts, radiator, hoses, fuel lines, flywheel, shocks, distributor, AND. .....a chasis harness from Painless (totally THRILLED with the harness). 
I'll be completely done with the project Thursday and will post pictures sometime Thursday night/Friday morning.  I've been going non stop for three weeks and I'm excited, ready to drive it, and ready to clean my garage. 
Here's my question -
I've got a sending unit wire....can I wire both sending units to the same wire?  Here's another question - I've got a manual valve to switch the dual tanks and an electric switch that controls just the fuel gauge on the dash.   Any wiring diagram for that?   Any input?  Comments?   I'm not exactly sure how to wire that without screwing something up.
As always.....I appreciate the help.

Title: Re: Fuel Tank Sending Unit Wiring
Post by: LTZ C20 on November 04, 2014, 04:55:47 pm

I think the best idea would probably be to use the stock fuel tank switch and valve. It allows you to switch tanks and send signal to the gauge. That way, when you flip the switch to change tanks it switches signal for the gauge and changes the valve to the other fuel tank. If you look up the wiring diagrams in the tech section you will see its a pretty simple setup. If it's a carb engine try looking at a say 78 or 79 wiring diagram,  if it's fuel injected try say 86 or 87 wiring diagram for TBI engines.

Title: Re: Fuel Tank Sending Unit Wiring
Post by: theaddictedchef on November 04, 2014, 06:23:51 pm

Thanks for the reply.   I'll post pics as soon as I am done. 

Title: Re: Fuel Tank Sending Unit Wiring
Post by: LTZ C20 on November 05, 2014, 12:48:27 am

Ok sounds good. Good luck!

Title: Re: Fuel Tank Sending Unit Wiring
Post by: hatzie on November 05, 2014, 06:28:03 am

The OEM GM Service, Unit Repair, And Wiring manuals are here---->http://forum.73-87chevytrucks.com/smforum/index.php?topic=25639.0
Chris doesn't have a couple of my latest scans.  If you need the 1984 CK wiring scan it's here--->http://www.mediafire.com/download/9ih3gy2t94wadpt/X8430_1984_GMC_CK_Light_Duty_Trucks_Wiring_Manual.pdf

The GM manuals are a bit more complete than the one size fits all multi-year diagrams.

Title: Re: Fuel Tank Sending Unit Wiring
Post by: LTZ C20 on November 05, 2014, 09:44:56 am

Yes they are. I consult my gm shop manual once in a while for exact specifics.

Title: Re: Fuel Tank Sending Unit Wiring
Post by: theaddictedchef on November 05, 2014, 10:00:20 am

Thank you hatzie!