But would it go from working to not working? And I'm wondering if its something else since the last one was doing the same thing which led me to get this one. I just don't know what else would do it since it can't be electrical. I going to go blow in the rear fuel line since its not hooked up and see if maybe its blocked from autozone and maybe the mechanical pump vacuum off the motor is making it open due to suction.

 

Well that was not it. I even rechecked the old one off the battery and it works just fine. It has to be something external from the selector valve keeping it from coming off of the aux port since its pulling from that tank and not the default rear tank when power is not applied. Could my fuel pump be sucking it open regardless of power or no power? That about all i could think of now.

 

i've never heard of a fuel pump sucking one open, but you can try hooking up your mity-vac to it and see if you can get anything weird to happen

 

I've never heard of a pump doing this, either. Josh has a good idea, try to replicate it on the bench.

 

I just tried and looks fine. Maybe i am just being an idiot but how many minutes would it run on fuel in the line. I am just going to put in on rear tank tomorrow and see if it chokes out and hook the rear fuel line thats not hooked up to the vacuum gauge and see if its pulling the normal amount of suction.

 

I can't say I know for positive, but I'd think it'd definitely be less than 5 minutes (at idle).

 

it seems to me that you either have a really weird issue here, or we aren't diagnosing things right. you might try putting a bucket of fuel under the truck and run clear hoses from both sides of the selector valve into the bucket, so they're able to suck fuel from it. then start it up and see where the flow is really at.

this is just too simple of a system to have problems this complicated...

 

That's what I figured as well especially with a 750 carb and at high idle due to the cold.

 

I agree it shouldn't be this complicated with a simple solenoid selector. I didn't think of putting two clear lines on to see what was happening but that is actually real smart thinking. If I don't figure it out early tomorrow I'm going to try this and that should be a sure fire way to see where it's pulling from. For over a decade I've taught the "keep it simple stupid" mentality and now here I am over thinking things and should have been keeping it simple. Thanks for the idea.

 

Well went out this morning and it worked fine Twice. Maybe both were sticking so I'm going to put the original back on since it had a boot over the power and the new one doesn't. I don't want a open spark by fuel lines if I don't have to. Putting on the tank now and I'll let you all know how much room I have from exhaust to pipes when it's bolted in for everyone's opinion. I couldn't find any heat reflector that I could apply to the tank without ordering it and I need the truck running ASAP so I think if I have over 2 inches all around it'll be fine.

 

I have one spot that is 2 inches away from the pipe and it tapers away to about 3 inches but the rough average is about 2 1/2 inches. Looking at it I believe it should be fine. Any thoughts?

 

it'll probably be ok, but i would be more comfortable with a heat shield in there.
as i mentioned earlier, it'll stay cool on a full tank, but when the tank is empty it might get hot enough to be an issue.
for a heat shield, you can use just about any piece of sheet metal - even old license plates, roof flashing, etc. it doesn't need to be fancy, it just needs to be a barrier against radiant heat

 

I'll probably run off the front tank until I can get something made or find some heat shield to stick to the tank and under the straps. Now I just need to figure out the best place to put my painless accessory fuse block I just got today. I'm thinking about the passenger side mirrored from the main block on the drivers side but am not a fan of cutting the firewall heat/noise wadding but may not have a choice. I had to get one as I couldnt justify running wires under other fuses anymore. Thanks for the help Josh!