Dual tanks - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mcssls · 01-15-2007, 07:51 PM

I have dual tanks on a 76 stepside 4x4. When I swith the factory switch the guage is all that changes, there's no sound or hit that it will try to switch. I'm sure I need a new selector valve. Strange part is there's a switch on the door side of the column that someone added. When I hit it it sounds like a dry fuel pump, under the truck whatever this is looks stock. Looks too big for what I think of as an electric pump. Any ideas? Is it original? If so what is it?

jpoutlaw · 01-15-2007, 08:37 PM

My '77 has the switch on the drivers side down low. It's just a toggle switch but it's original. My gauge changes, no sounds 'cause there's only one fuel pump up front pulling the fuel.

I doubt it's original but someone may have tried another fuel pump at one time. Maybe to help prime the other??? Don't know 100%.

blink32 · 01-15-2007, 08:45 PM

The actual switching mechanism is very small and a bit back from the drivers seat so I wouldn't expect to hear any audible switching in the first place. I've never heard any noise on any of the 3 I've owned with dual tanks. If the gauge readings change then its most likely operating normally.

For the other switch, take a picture and post it? Would help seeing it.

mcssls · 01-15-2007, 09:04 PM

yeah, I'll have to take a pic tomorrow if I'm feeling human again, right now am feeling pretty ford like.

boxrodz · 01-15-2007, 10:07 PM

Quote:

Originally Posted by mcssls

... Strange part is there's a switch on the door side of the column that someone added. When I hit it ...

I thought you were leading up to a 'Stephen Wright'-like joke:
“I have a switch in my apartment that doesn't do anything. Every once in a while I turn it on and off. On and off. On and off. One day I got a call from a woman in France who said "Cut it out!"”

I know the '81 and up have a different selector valve, but I can hear the operation of the solenoid inside the selector valve once I hit the switch. The selector valve changes both the fuel sending unit signal (to the gauge) and fuel pickup between the two tanks. ... interesting that you have another switch.

79BIG10 · 01-17-2007, 12:31 AM

Sounds like what happened to mine. Look for a pink wire at the fuse box that has come loose. This is a power wire to the factory switch that powers it. You're gauge will still move but it won't power the valve.

mcssls · 01-18-2007, 08:33 PM

got the flu 5 days ago, haven't done anymore than stand on the porch and look at the truck. Maybe I'll get closer this weekend.

wklink · 01-18-2007, 10:44 PM

My 79 GMC makes no noise when it switches tanks. I know it works because I haven't run out of gas yet

01-15-2007, 07:51 PM	#1
mcssls Registered User Join Date: Jan 2007 Location: Phoenix AZ Posts: 9	Dual tanks I have dual tanks on a 76 stepside 4x4. When I swith the factory switch the guage is all that changes, there's no sound or hit that it will try to switch. I'm sure I need a new selector valve. Strange part is there's a switch on the door side of the column that someone added. When I hit it it sounds like a dry fuel pump, under the truck whatever this is looks stock. Looks too big for what I think of as an electric pump. Any ideas? Is it original? If so what is it?

01-15-2007, 08:37 PM	#2
jpoutlaw Registered User Join Date: Dec 2006 Location: Idaho Posts: 42	Re: Dual tanks My '77 has the switch on the drivers side down low. It's just a toggle switch but it's original. My gauge changes, no sounds 'cause there's only one fuel pump up front pulling the fuel. I doubt it's original but someone may have tried another fuel pump at one time. Maybe to help prime the other??? Don't know 100%. __________________ JP 1977 GMC Sierra Grande (350) 2004 Jeep Wrangler (4.0)

01-15-2007, 08:45 PM	#3
blink32 Registered User Join Date: Dec 2003 Location: OTR Posts: 338	Re: Dual tanks The actual switching mechanism is very small and a bit back from the drivers seat so I wouldn't expect to hear any audible switching in the first place. I've never heard any noise on any of the 3 I've owned with dual tanks. If the gauge readings change then its most likely operating normally. For the other switch, take a picture and post it? Would help seeing it.

01-15-2007, 09:04 PM	#4
mcssls Registered User Join Date: Jan 2007 Location: Phoenix AZ Posts: 9	Re: Dual tanks yeah, I'll have to take a pic tomorrow if I'm feeling human again, right now am feeling pretty ford like.

01-17-2007, 12:31 AM	#6
79BIG10 I'm back with 2nd truck! Join Date: Feb 2002 Location: Texas Posts: 3,775	Re: Dual tanks Sounds like what happened to mine. Look for a pink wire at the fuse box that has come loose. This is a power wire to the factory switch that powers it. You're gauge will still move but it won't power the valve. __________________ 1979 Chevrolet Bonanza Big10 "Tootsie Roll" 1985 Chevrolet Silverado (wife's) Member of the Southern Bowties Club "Don't underestimate how sexy a fat man who drinks to excess can be." Homer Simpson

01-18-2007, 08:33 PM	#7
mcssls Registered User Join Date: Jan 2007 Location: Phoenix AZ Posts: 9	Re: Dual tanks got the flu 5 days ago, haven't done anymore than stand on the porch and look at the truck. Maybe I'll get closer this weekend.

01-18-2007, 10:44 PM	#8
wklink Junior Member Join Date: Sep 2006 Location: Olympia, WA Posts: 122	Re: Dual tanks My 79 GMC makes no noise when it switches tanks. I know it works because I haven't run out of gas yet __________________ I let my 16 year old son drive my every car that I own. I don't let him drive my truck. A man has to draw a line somewhere.



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