Good job on the video! That is really interesting. I assume, but am not sure that the Racor is showing:

1. a fuel restriction before the filter which could mean that your fuel pickup foot is jammed down against the bottom of the tank causing a fuel restriction, but that is just a guess; or

2. suction is broken by air intrusion somewhere along the pre-filter fuel line. In other words, it is not that the pump is not pulling enough fuel, it is that the pump is pulling air and that is why you are seeing less fuel in the filter; or just the opposite below,

3. there is a vacuum in the tank/pre-filter fuel line which is caused by some failure to vent (I believe it is a closed system to prevent evaporative emissions) or some failure along the fuel return line.

Considering that you hooked up the two gas tank ports together with hose, no. 3 could be your problem. The ports are not connected in any way with the oem tank I have. So disconnect those hoses. It is possible that the ports that you have connected together are basically one-way check valves which are meant to be exposed to air? (I don't remember when I gutted one of mine to install the 1/8" fuel pickup tubing for my Webasto diesel furnace.) In other words, look at one closely does it have a diaphram which lets air into the tank so as to break up a tank vacuum to let fuel be sucked up by the fuel pump (but not fumes out)?

I am interested to see what others have to say...

 

UPDATE: Got it all figured out. Had to drop the tank again to find the problem. The pickup was too long, so Tim's #1 was definitely the issue. Some symptoms that led me to that conclusion (other than removing the sending unit):

1. Vacuum was created BEFORE the filter. The only place a vacuum could be created is at the pickup itself or a sealed tank.

2. When I accelerated hard I heard a steel pop, almost like when you pop the lid of a metal jar lid. When I would let off the accelerator, it would pop again. My guess was this was the tank bending under the pickup suction.

3. Symptoms remained with the filler cap removed, so it couldn't be vacuum in the tank when sealed.

4. The sending unit didn't sit well when I bolted it in. I should have taken more care when installing.

A simple 1/4" cut of the pickup tube solved everything. Buttoned her back up and not only does she run great, but I filled her up for the first time since owning her without issue! That's a victory in my book. Plus, now I have an extensive knowledge of the fuel system And I know what I am working with.

Tim, let me know what I owe you for the parts. Never got an invoice. Thanks again for the help!

 

jrodared: First congratulations! Second, sweet looking rig! Third, you should definitely spend some time over at sportsmobileforum.com Fourth, don't be a stranger here. You have acquired and will acquire more knoweledge and experience about your 7.3L engine which others could and will benefit from. pay it forward...

 

I'll check it out and keep posting as I learn more about the rig for sure. Thanks again!

 

Well you know you weren't drawing any air in and the system was tight. Good job, glad it's fixed.

 

Figured I'd post a few more pics of the van

 

OK. Now I want to see pictures of the engine compartment top and bottom...

 

A Perfect spot for a pop-up Automatic Chain Gun Turret. Just Sayin......

 

It used to be a Fox News van in Philly. Onboard air to raise the mast, inverters for all the electronics, etc. The vehicle was originally manufactured by a company called Frontline. Frontline Communications - Manufactures Mobile Command Vehicles, Broadcast Trucks and Communications Trailers

I've got the electronics disconnected to eliminate it from some chagrinning issues, but will get it back online. Had to drop the air tank too when working on the fuel tank. Haven't had a chance to mess with the rooftop air yet, but I think it works. Had to get a new plastic housing for it cause it was leaking. Could always convert to a sunroof? hehe.

I'll post some more pics this weekend when I am out there.

 

The black rectangle looks like an ECU for an Auragen/Viper 7500 Watt generator which will be mounted on the top alternator position on the 7.3L.


http://aurasystems.com/documents/906203_AUR_proof07.pdf


If you still have it. Keep it. It will do 220v and 100v. It will power your house when the lines go down. It is a $7.5K to $10K device new.