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Aux Tank [message #341336] Tue, 26 February 2019 08:18 Go to next message
skip2 is currently offline  skip2   United States
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I'm having cranial flatulence this morning, Have I been mistaken all this time. isn't the rear fuel tank considered the main and the front the one with the extra fuel capacity aka "AUX". Just confused.

Skip Hartline


74 Canyon Lands, FiTech, 3.7 FD LSD, Manny Tranny, Springfield Distributor, 2001 Chevy Tracker Ragtop Towd
Re: Aux Tank [message #341338 is a reply to message #341336] Tue, 26 February 2019 08:33 Go to previous messageGo to next message
RF_Burns is currently offline  RF_Burns   Canada
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Skip,
You are correct, rear is the "Main"

I actually use the Aux tank more than the main tank. Reason being is the placement of the filler tubes at the front of the tanks. This means once you get down on fuel, more fuel tends to stay in the front tank, or more correctly more fuel empties from the back tank.

Consider braking, fuel flows to the front of the tanks causing the rear (Main) to empty into the front. Going downhill, same thing, rear empties into front. Braking going down hill even more so... I've seen 1/2 main tank goto empty and my Fuel Injection engine stall... all the fuel is in the front Aux tank.

Just my experience




Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
Re: Aux Tank [message #341343 is a reply to message #341338] Tue, 26 February 2019 09:15 Go to previous messageGo to next message
skip2 is currently offline  skip2   United States
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Exactly what happened this weekend, let my tanks get lower than I like, I'm running high pressure pump off of tanks with return for fitech and it didn't like it till I went to front.
Skip Hartline


74 Canyon Lands, FiTech, 3.7 FD LSD, Manny Tranny, Springfield Distributor, 2001 Chevy Tracker Ragtop Towd
Re: Aux Tank [message #341344 is a reply to message #341336] Tue, 26 February 2019 09:17 Go to previous messageGo to next message
skip2 is currently offline  skip2   United States
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Another thing to think about is when you let the fitech run out of fuel it's almost like priming a diesel.

74 Canyon Lands, FiTech, 3.7 FD LSD, Manny Tranny, Springfield Distributor, 2001 Chevy Tracker Ragtop Towd
Re: Aux Tank [message #341345 is a reply to message #341344] Tue, 26 February 2019 09:22 Go to previous messageGo to next message
Justin Brady is currently offline  Justin Brady   United States
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skip2 wrote on Tue, 26 February 2019 09:17
Another thing to think about is when you let the fitech run out of fuel it's almost like priming a diesel.
If you run it out you can cycle the key a few times to get it up and going again (it puts a bit prier squirt in when you initially turn the key to ON, so if you do it a few times it will get the air out of the line)


Justin Brady http://www.thegmcrv.com/ 1976 Palm Beach 455
Re: [GMCnet] Aux Tank [message #341347 is a reply to message #341344] Tue, 26 February 2019 09:30 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
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You guys ever hear about driving off of the top half of the tank instead of
the dregs? In tank fuel pumps like to be completely immersed in fuel, not
sloshing around in a large flat area barely covered with what passes for
gasoline these days. Would be nice if there was a well or a depression in
our tanks that the pump could be located in, but there isn't. My advice,
keep more fuel in your tanks.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

On Tue, Feb 26, 2019, 7:18 AM Skip Hartline via Gmclist <
gmclist@list.gmcnet.org wrote:

> Another thing to think about is when you let the fitech run out of fuel
> it's almost like priming a diesel.
> --
> 74 Canyon Lands, FiTech,
> 3.7 FD, Manny Tranny,
> Springfield Distributor,
> 2001 Chevy Tracker Ragtop Towd
>
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Re: [GMCnet] Aux Tank [message #341350 is a reply to message #341347] Tue, 26 February 2019 10:09 Go to previous messageGo to next message
skip2 is currently offline  skip2   United States
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Went to top off tanks but pumps were down at my usual spot and I assumed I would be ok, everyone knows what ASSUME means.

74 Canyon Lands, FiTech, 3.7 FD LSD, Manny Tranny, Springfield Distributor, 2001 Chevy Tracker Ragtop Towd
Re: Aux Tank [message #341351 is a reply to message #341338] Tue, 26 February 2019 10:28 Go to previous messageGo to next message
roy1 is currently offline  roy1   United States
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My 2 cents. If you are low on fuel and are on a white knuckle run trying to find a gas station you better pay attention if you are going up hill switch to the rear tank or you will likely run out of fuel during the climb. Then switch back to the front tank going down. Then repeat as you go. Pretty soon the low fuel light will light on each tank as the fuel level goes down and the gas station will appear. You won't do this more then once at least that was my experience .

Roy Keen Minden,NV 76 X Glenbrook
Re: [GMCnet] Aux Tank [message #341354 is a reply to message #341347] Tue, 26 February 2019 11:00 Go to previous messageGo to next message
BobDunahugh is currently offline  BobDunahugh   United States
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Back when we used the original fuel selector valve. And the dash fuel tank selector value switch is in the Aux tank position. That meant that the selector valve at the rear was turned on all that time. Not a big deal. But I had the thought that if it's not turned on all the time. Thus since it's off. Less is apt to go wrong internally. ( YES. Me being annul over simple things again. ) So I just run on the main tank all the time. And when I think I'm in need of around 20 to25 gal. I take a brake to fill up. How with the Howell/GM EFI fuel return. And a pump for each tank. It seems that most of that returned fuel. Goes to the rear main tank. I do run the aux tank pump some just to check that it's OK. But then I end up filling the main tank up with the return fuel from the EFI. This may help those that live around mountains. Bob Dunahugh
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Re: Aux Tank [message #341360 is a reply to message #341336] Tue, 26 February 2019 13:04 Go to previous messageGo to next message
jhbridges is currently offline  jhbridges   United States
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Bob, if running an hour or three doesn't hurt the valve (it won't) you can figure it is made to run continuously (it is). The original valves fail for the same reason the original fuel hoses fail - the rubber gets destroyed by the alcohol in current gasoline. My solution on the 23' was the dual pumps shown in the photo gallery. I will probably do that with the current coach.

=--johnny


Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell
Re: [GMCnet] Aux Tank [message #341361 is a reply to message #341354] Tue, 26 February 2019 13:35 Go to previous messageGo to next message
GatsbysCruise is currently offline  GatsbysCruise   United States
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BobDunahugh wrote on Tue, 26 February 2019 11:00
Back when we used the original fuel selector valve. And the dash fuel tank selector value switch is in the Aux tank position. That meant that the selector valve at the rear was turned on all that time. Not a big deal. But I had the thought that if it's not turned on all the time. Thus since it's off. Less is apt to go wrong internally. ( YES. Me being annul over simple things again. ) So I just run on the main tank all the time. And when I think I'm in need of around 20 to25 gal. I take a brake to fill up. How with the Howell/GM EFI fuel return. And a pump for each tank. It seems that most of that returned fuel. Goes to the rear main tank. I do run the aux tank pump some just to check that it's OK. But then I end up filling the main tank up with the return fuel from the EFI. This may help those that live around mountains. Bob Dunahugh
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*** ***

My understanding of the fuel storage system is the fill hoses, which are huge, are mounted a little above the halfway point on both tanks.
if you lose the use of the selector valve, you have access to 75% of your stored fuel given on flat and mild hills.
That would figure fuel access at about 37.5 gallons or 375 miles.

This if figuring 25 gallons of the supply tank plus the top half (12.5 gallons) of the other tank which is still filling the supply tank via the fill line through gravity.

Sort of sketchy if you are relying on this real time but works by the numbers.


GatsbysCruise. \ 74GMC260 Former Glacier Model style. \ Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO - UBUNTU VOYAGER - Berzin Auto Center
Re: [GMCnet] Aux Tank [message #341367 is a reply to message #341354] Wed, 27 February 2019 02:01 Go to previous messageGo to next message
BobDunahugh is currently offline  BobDunahugh   United States
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Johnny. I know that those valves are made for continuous duty. As I said. Me being anal over simple things. I ran myself out of gas on the road due to a tank valve going bad. So I start looking for gas at half tank ever since. Bob Dunahugh

________________________________
From: Bob Dunahugh
Sent: Tuesday, February 26, 2019 11:00 AM
To: gmclist@list.gmcnet.org
Subject: RE: Aux Tank

Back when we used the original fuel selector valve. And the dash fuel tank selector value switch is in the Aux tank position. That meant that the selector valve at the rear was turned on all that time. Not a big deal. But I had the thought that if it's not turned on all the time. Thus since it's off. Less is apt to go wrong internally. ( YES. Me being annul over simple things again. ) So I just run on the main tank all the time. And when I think I'm in need of around 20 to25 gal. I take a brake to fill up. How with the Howell/GM EFI fuel return. And a pump for each tank. It seems that most of that returned fuel. Goes to the rear main tank. I do run the aux tank pump some just to check that it's OK. But then I end up filling the main tank up with the return fuel from the EFI. This may help those that live around mountains. Bob Dunahugh
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Re: Aux Tank [message #341369 is a reply to message #341336] Wed, 27 February 2019 08:01 Go to previous message
jhbridges is currently offline  jhbridges   United States
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The dead motor showed such variable consumption that I always did the same. 125 - 150 miles and buy gas. I have put as much as 30 gallons in at 150. It has a selector valve and a high pressure pump for the MSD injection. I have a spare pump, I'm thinking I'll install it with a relay just like the low pressure ones in the 23'. I'll still have the lifeboat out back though Smile

--johnny


Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell

[Updated on: Wed, 27 February 2019 08:02]

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