Jim,
If my understanding is now correct to use all the fuel I must first let the
main tank run 'till it's dry then switch to the aux. In the past I've
switched when the main got very low but not dry which left unused fuel in
the main tank.
I guess it doesn't make any difference how this system works as long as we
understand how to use it to the max.
Dick
>Sam,
>My computer has been down for several days and I have not been able to get
>on the net, hope this input is not stale.
>
>You are right, the fuel set up is a bit unusual in that there are 2
>tanksbut they only act as one. It would have been better to label the
>switch "aux. fuel on/off" as opposed to main/aux.
>
>The rear tank is the main tank and the pickup for the generator comes off
>it at 1/4 full level. This is done to prevent you from running the beast
>out of fuel with the generator. When the rear tank, which by the way is
>tied to the front tank (aux.) at the 1/4 level as well drops the fuel level
>below the pickup, the generator shuts down. When this happens, you have
>1/4 tank i both tanks. You can run the 1/4 tank out of the rear (main)
>tank then switch to the front (aux.) tank and suck the 1/4 out of it to get
>you to the next gas station.
>
>You need to look at the fuel switch as one tank and think of the "aux."
>position as a 1/8 tank reserve to get you to the next exit if needed. This
>logic will keep you out of getting excercise walking to the next stop. I
>would not rely on the aux. tank except in extreme situations. The 2 tanks
>act as one until the 2/4 level so it is unnecessary to use the switch. I
>have a situation right now on a coach where the customer has had to hoof it
>for fuel and could not figure out what happened. In working with the
>system, I found the front tank would not pick up fuel. The problem eather
>lies in the A/B switch or the pickup filter sock in the tank has colapsed.
>Whatever the problem, when you select "aux." the coach sputteres and shuts
>down. To repair this malidy, I will have to do some more testing and
>probobly drop at least the front tank and check the sock and pickup. My
>suspishion is we will wait until after the Marion rally to do all of that.
>As it is, the coach will have 7/8 of the fuel available and the 1/8 of the
>total that is in the front tank will be unusable.
>
>There has been a great deal of talk about seperating the fills on the fuel
>tanks in the past, but in doing that a dealer would be assuming a great
>deal of liability which in todays "sue me" society would be bad. You would
>probobly pick up better fill characteristics seperating the inlets but as
>weird as it may sound, I like the idea that one pickup can access all but
>1/8 of the available fuel. This way, you are not relying on the fuel A/B
>selector valve to give you access to 1/2 of the fuel. I have seen that
>valve of control circuit fail and seen big trucks act like yo-yo's stopping
>frequently because they could only get at 1 tank.
>
>I said all of that to say, even as unusual as the fuel system is, think of
>the "aux." fuel setting as an emergency reserve only to be used in a thermo
>nuclear exchange and you will not run out of fuel. Let the genny shut down
>at 1/4 tank and remember that 1/4 will drop like a rock because you will
>actually be accessing the 1/8 tank of the main tank while holding back the
>1/8 in the aux. tank for the emergency get along. If you think about it
>that way, it works pretty good.
>
>Hope this helps.
>
>Jim Bounds
www.gmccoop.com
>-----------------------------------------------------
>>Even with isolation and seperate filling there isn't a need for two guages,
>>only one accurate guage will do. Accuracy is the problem and always was with
>>GM cars or whatever. I think GM does better now however.
>>-----Original Message-----
>>From: robteed
>>To: Gmcmotorhome Org
>>Date: Wednesday, August 19, 1998 9:20 PM
>>Subject: Re:GMC: Dual Gas Tanks
>>
>>
>>>Has anyone separated the Fuel Tanks. Put Fill Tubes
>>> to each tank? Two Gas Gauges ?Wouldnt this make for a better setup.
>>> Then You would know exactly how much gas You have
>>> in each Tank. I think I will do this to my 74 GMC.
>>> Rob Teed
>>>
>>
>>
>>
>
>
