You are correct Nollaig and that is what I've been saying all along contrary to conventional wisdom and what other members have been staing and what I've been saying all along.In a dual tank setup for 78+9 f series trucks THE REAR TANK S CONSIDERED THE AUX and the FRONT IS CONSIDERED THE MAIN

 

Has your truck been fiddled with ?

Mine hasn't.

Mine is how it came from the factory.

Perhaps the factory employees reversed the wiring harness on a select amount of trucks.
All I know is mine for sure has not been tampered with since it left the factory.
switch **** DOWN = The Front AUX is being used

Switch **** UP = The Rear MAIN tank is being used.

And that's all I have to say about that...

 

Mil1ion Your contradicting yourself in the same thread/Earlier in the thread on page 1 you provide a picture of your own trucks LABELED gas switch.It clearly says Aux up and MAIN is down/Now in your latest quote that I just copied you say **** down is AUX and up is Main So what are you saying.The way I see it is that your validating what my point is

 

Sounds like you reversed the fuel selector switch or wiring.

Yup, fill 'er up and report back too.

 

Every repair manual, including my factory repair manuals and documentation, oppose what you are saying.

Look at from this point.

Where is the SINGLE TANK SYSTEM MOUNTED? Between the frames aft-of-axle. This is considered MAIN, because, it's pretty much the only gas tank, correct?? IT'S THE SAME FOR THE DUAL FUEL SYSTEM. PERIOD. END!

 

Great post.

All I know is that on MY truck, the dash says "front" and "rear". And as the rear tank leaks...I don't put any fuel in it. I run the front tank full time and don't mess with my switch and she keeps on keepin' on...

 

Well for my 2 pennies, MY 77 the Main is the IN-CAB tank, and the AUX is the rear tank behind the rear axle,,,, nothing has been diddle with either, must be the tank monkies jackin-around again?!!>!

 

All of this...and NOONE has answered the poor guys question about whats keeping his truck from running...stop fighting and start helping already.

Regardless of which tank it is which he states hes not getting fuel flow. Im certain that hes switched the switch back and forth trying to suck what little he can out of both.

To find out if its a fuel pump issue...dissconnect the fuel line from the front of the carb and put it in a coffe can..then tap the starter a couple times...if there is gas in the can then your fuel pump is working. If no gas then you may need to replace the pump or just the fuel filter

If you ran out of gas you may have use a bit of starting fluid to get the engine to draw vacuum and refill the bowl on the front of the carb before it will start again.

To find out which tank is which... just fill one tank and repeat the process till you get it fired up. To diagnose what the issue us you have to check each system one at a time...start with the fuel pump as thats the easiest to check...then move on down the line.

Hope that helps somewhat,
-Chris

 

I'd like to add this...I have a 1977 which I bought new with an in cab tank. Driving home from the dealer I put gas in the rear tank thinking it was the main. The gauge read 1/2 full and I promptly ran out of gas. To make a long story short, it turned out the fuel was being drawn from the OTHER tank not the one registering on the gage. This may be your problem. I solved mine by switching the fuel hoses on the valve located under the drivers door. I still don't know which was connected right, the gauges or the hoses. Good luck

Don

 

And to get off the subject once again..... Dennis, I wish I could find one of those Pioneer supertuners with cassette. They are going for $100 plus on e-bay for well used ones. Any ideas?

 

For what its worth

Main=Front/mid/side tank

Aux= Rear/behind axle tank

Only change I made was the switch unit and plugged in the way it came off.

Have fun with that.

 

Not contradicating it all.

It's in the terminology.

You're presuming that the position of the **** means that tank that is being used.

ie: **** up means use AUX.. **** Down means uses MAIN Tank


But,Perhaps FORD is saying with the **** one direction OPENS the OTHER tank.

ie: **** DOWN shows AUX tank use...**** Up means MAIN Tank use.

 

Noone ?.. You mean Peter Noone of the band Hermans Hermit"s ?

No , you mean " No One ".......

The topic of the thread is "Aux Tank issue" .........not keeping the engine running.

This thread is more about which is Aux and which is Main because The O/P has to know which tank is which to determine of he has a problem with that particular Tank or ..the other one.

He is assuming One tank is Aux and the Other is the main.



ps Doug, I have a Pioneer S/T sitting in a drawer in my garage.

I used to pull them when I saw them at the wreckers.

 

This is going to be kinda off topic at first........

So shoot me Dennis....I forgot a space....its called a typo . Like I said in other posts I rarely take offense to things but I have to say this.....


Dennis you aren't the grammar police.... ok.....it isnt your responsability to go around pointing out people's typos making whole replies to things that really dont need pointed out. Like how to spell "vacuum" or "no one" ect ect ect.

People make mistakes and I'm sure that the realize them after they re-read them later in the day....without your help.

And yes from the areas in bold above Id bet his truck isnt running when he switches to that tank........if theres no fuel coming from the tank..... how will it run???

Magical gas pixies in the engine bay? I think not

The OP dosent have a clue as to why hes not getting any fuel from the tank regardless of which one it supposedly is or isnt...do you see my point now?

-Chris

PS He asked about the fuel pump as well....whats that hooked to Dennis?? Engine perhaps

I should add that I am not angry at this point....but more like irked.

 

The main reference to no one is because the running of the engine wasn't the main topic ..it was the result of a possible.


You are correct about not being the spelling and grammar police.
If I was I would do things entirely different.
My apologies.

I only make mention of things like Noone in a light-hearted way.

Unfortunately there isn't a smilie I could use that denotes that.


Right now we need to resolve which tank is actually which for the OP.

Switch **** position vs Ford original design and operation.

I have always considered the Rear Between the Frame Tank as the Main because on trucks that just have that one tank..that's its location.

Fuel Tank **** direction right now is a stumbling block.

IMO, When trucks only came with a behind the seat tank..that was the main.

Too Bad we don't have a Ford Archive person on the forums.

I have asked them to come here several times to help clear things like this topic up.