23 Gallon gas tank help - no fuel issue

[Heus33]

Gas tank gurus I need some advice.

New 23 gallon Aero tank.
New fuel lines
New mechanical fuel pump
New electrical fuel pump

**sometimes** I get a trickle of gas to the carb. Sometimes nothing. I thought it was pump related so I swapped out the old mechanical pump with a new one and it sporadically worked again. Then nothing. So I added an electrical in line pump and still nothing.

I have about 18 gallons of gas in the tank but can't get any flow to the carb.
The lines are clear.
I also tried pressurizing the tank but that was useless too.

What am I missing?

@migs - this is the tank you installed on Pete's bronco back in the day. Anything you recall?

 

[tasker]

Pressurized cap? try it with out gas cap on?

 

[Heus33]

Pressurized cap? try it with out gas cap on?

Its just the stock gas cap. I haven't tried it without the cap on. I can try that!

 

[Brush Hog]

Mechanical fuel pump not under the eccentric? Dual tank fuel selector switch in wrong position (I just installed a new pump and did this thought new pump was bad). Leak in fuel line somewhere. Tank not venting.

 

[73azbronco]

didnt see mention of fuel filter?

Using a pressure gage, does pressure never rise, or does it rise slowly.

You have both a mechanical and electric pump?

Has it ever worked?

How old is gas?

 

[Shimmy]

any chance there's a plug still in one of the fittings? some times these new fittings of sorts come with a rubber plug stuck in them. it's easy to overlook one of these plugs in the AN fitting. something like this

 

[gnpenning]

Where is the electric pump mounted?

Do you have fuel coming thru the outlet?

If not, work back. If so work forward. You need to break it down in sections.

 

[Heus33]

Mechanical fuel pump not under the eccentric? Dual tank fuel selector switch in wrong position (I just installed a new pump and did this thought new pump was bad). Leak in fuel line somewhere. Tank not venting.

Its on the eccentric - it will pump some gas, just not always and not consistently.

For the fuel tank selector - this Bronco did have dual tanks at one point but all of that has been removed. There's only one fuel line running from the new 23 gal tank to the pump. I dont think the selector switch would be in play any longer, right?

No leaks in the lines.

Could be a venting issue though - I'm going to try it without the cap on as Randy also suggested.

 

[Heus33]

didnt see mention of fuel filter?

Using a pressure gage, does pressure never rise, or does it rise slowly.

You have both a mechanical and electric pump?

Has it ever worked?

How old is gas?

I have one of those cheap clear filters on right before the carb just so I can see if its pumping.

I'll have to put a pressure gauge on it, that's a good idea.

I have both mech and electrical now.

I got "some" gas out of the new mechanical pump but it wasn't consistent and would seem to lose prime which is why I tried the electrical pump route.

Gas is new, just put in about 18 gallons.

 

[Heus33]

any chance there's a plug still in one of the fittings? some times these new fittings of sorts come with a rubber plug stuck in them. it's easy to overlook one of these plugs in the AN fitting. something like this

I'm getting some gas and have pulled the lines, no fittings stuck.

 

[Heus33]

Where is the electric pump mounted?

Do you have fuel coming thru the outlet?

If not, work back. If so work forward. You need to break it down in sections.

I mounted the electric pump near the driver's side fender skirt.
No fuel coming out of the outlet. I've worked back to the tank and that's where I'm stuck now.

 

[migs]

Tom, back when I installed that tank I don't believe that I was tasked with installing the filler hose or any of the lines, and I noticed on your other thread that the filler hose was on your list of items to get. Well, if it has indeed been sitting with an open filler neck inside the barn for the past five years I'm thinking maybe some critters have made their way inside. debris could be causing those issues you describe.

 

[Heus33]

Pete had everything taped off and I blew out the tank before I put gas in it.

I am fairly confident it’s clean inside


Sent from my iPhone using Tapatalk

 

[gnpenning]

I mounted the electric pump near the driver's side fender skirt.
No fuel coming out of the outlet. I've worked back to the tank and that's where I'm stuck now.

Is the tank still in the vehicle?

I think I saw where you blew through the line back to the tank and it was clear??

The pick up in the tank may have come off or has a leak.

If the tank isn't out it's going to need to come out.

Just to make sure, pull the inlet side off the electric pump and put it in a gas can. With all necessary cautions in place try starting it.

 

[4xfun]

Sounds like the fuel pickup line is clogged. Have you pulled the assembly? We have a pesky insect called a mud dauber that will pack mud into any hole it can find. The result is very impressive. You could be pulling a little bit of gas and a lot of debris through the line.

If you don't want to pull the assembly, try putting a vacuum pump on your line from the tank to see if you are getting any flow through the line. You may be able to push air into the line, but that will just put the debris back into the tank. Once you get everything flowing, you may want to add another filter in the line to protect the pumps. Summit has a nice visual and guide https://help.summitracing.com/knowledgebase/article/SR-05376/en-us. Of course, they are trying to sell fuel filters, but with all of the issues of fuel and poor fuel line materials, it is a good idea.

 

[EPB72]

Is ther a pickup fitting and a return or vent line on the tank maybe you got them mixed up,, blow into the tank with18 gallons fuel if line is submerged ther should be some resistance ,

 

[DirtDonk]

Two bad mechanical fuel pumps in a row is not uncommon. In fact, four or five defective mechanical fuel pumps in a row from the same supplier, is all too common!

An electric fuel pump needs to be a pusher, not a puller. In some cases they work, but in most they don’t. You need to mount an electric fuel pump back by the tank.

But before that, insert a short hose from the inlet of the pump into a can of gas. If it pumps fine, then you know the pump is working. If it doesn’t, then you have an, also all too common defective electric fuel pump.

This is not to discount any of the other mentioned things that can go wrong, such as air bleeding in, or simply difficult priming, or the tank not being invented properly.

Speaking of which, what year is your Bronco?
Unless the whole filler neck assembly has been changed, the year dictates what type of cap you have. If it’s a 70 or earlier, it’s a fully vented cap. If it’s a late 70 or later, it’s a sealed cap. Meaning it only vents inward and not outward.
This sometimes does not work sufficiently enough on its own, without the other vents working.
Are the tank vents hooked up to a charcoal canister? Or are they capped off?

Are you sure the pump is connected to the outlet tube? I’m guessing there is only one in the 3/8 inch size, but I’m not sure where the Aero tank pick-up is on a non-Efi set up.
Is the pick-up part of the tank, or is it part of the sending unit module?