Dual tanks, advice from the savvy - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cfan10 · 01-01-2012, 08:25 PM

How to use both tanks again, ex-mechanic did something to the switch, (electrical) it gets no power. No noise when switching. Bolt in cut-down hose on switching valve, is it possible that mechanic installed switch valve wrong? Because it didn't work right, as it would shut off. This is why he switched to one tank. Brand new switching valve.

Everything worked fine when I bought the truck, all this bs just wanting gas gauge to work, it acted more like a clock. And still doesn't work. I'm tired of wasting gas due to overflow from tank.

Any advice or experience on what to do, I want to use both tanks again.
How far does switch button wires run, and where are they supposed to go (connect to)

As always many thanks for your help. It is most sincerely appreciated.
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**hatzie** · 01-01-2012, 09:36 PM

What year is your truck? There are two different systems between 73 & 91.

pig rig · 01-02-2012, 12:11 AM

the easy way to tell witch switch you need is if your truck is a TBI truck or not the TBI switch also powers up the fuel pump

cfan10 · 01-02-2012, 04:19 AM

84 swb
305 cid
Posted via Mobile Device

beamn7 · 01-02-2012, 05:38 PM

From the 1984 GM manual....
Seems the editor that day was napping as both tanks were labeled "left tank". Best verify tanks by wire color....

**hatzie** · 01-02-2012, 10:32 PM

Quote:

Originally Posted by pig rig

the easy way to tell witch switch you need is if your truck is a TBI truck or not the TBI switch also powers up the fuel pump

The switch and selector valve are the same. The TBI tank wiring harness is different to feed power to the pumps.

**hatzie** · 01-02-2012, 11:14 PM

I attached the Dual Tank Parts Book Illustration pages and the NL2 Dual Tank wiring schematic.
Hopefully these will help you sort out what's wrong.

donut · 01-03-2012, 08:07 AM

Thanks for posting those hatzie, I'll be doing the "get my dual tank to work" thing soon.

01-01-2012, 08:25 PM	#1
cfan10 Registered User Join Date: May 2011 Location: Texas Posts: 984	Dual tanks, advice from the savvy How to use both tanks again, ex-mechanic did something to the switch, (electrical) it gets no power. No noise when switching. Bolt in cut-down hose on switching valve, is it possible that mechanic installed switch valve wrong? Because it didn't work right, as it would shut off. This is why he switched to one tank. Brand new switching valve. Everything worked fine when I bought the truck, all this bs just wanting gas gauge to work, it acted more like a clock. And still doesn't work. I'm tired of wasting gas due to overflow from tank. Any advice or experience on what to do, I want to use both tanks again. How far does switch button wires run, and where are they supposed to go (connect to) As always many thanks for your help. It is most sincerely appreciated. Posted via Mobile Device Last edited by cfan10; 01-01-2012 at 08:33 PM.

01-01-2012, 09:36 PM	#2
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 5,020	Re: Dual tanks, advice from the savvy What year is your truck? There are two different systems between 73 & 91.

01-02-2012, 12:11 AM	#3
pig rig Registered User Join Date: Feb 2009 Location: washington the state Posts: 730	Re: Dual tanks, advice from the savvy the easy way to tell witch switch you need is if your truck is a TBI truck or not the TBI switch also powers up the fuel pump __________________ my sports car rolls on six wheels only because I'm to fat to get in and out of new corvette http://hubgarage.s3.amazonaws.com/ph...ped_detail.JPG

01-02-2012, 04:19 AM	#4
cfan10 Registered User Join Date: May 2011 Location: Texas Posts: 984	Re: Dual tanks, advice from the savvy 84 swb 305 cid Posted via Mobile Device

01-02-2012, 05:38 PM	#5
beamn7 Registered User Join Date: Oct 2011 Location: Wildomar, CA Posts: 466	Re: Dual tanks, advice from the savvy From the 1984 GM manual.... Seems the editor that day was napping as both tanks were labeled "left tank". Best verify tanks by wire color.... Attached Images Last edited by beamn7; 01-02-2012 at 05:44 PM.

01-03-2012, 08:07 AM	#8
donut Registered User Join Date: Aug 2009 Location: S.C. Posts: 1,593	Re: Dual tanks, advice from the savvy Thanks for posting those hatzie, I'll be doing the "get my dual tank to work" thing soon. __________________ '86 C-30 dually, 454/tbh400 '73 K-20 350/350/205 (sold ) I'm kinda like duct tape- no real purpose, but handy to have around.



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