to fuel up on the way to work - the rear tank was fine but my front tank will not take fuel - even slow it burps immediately. I tried again today and it still won't....This is wierd to happen all of the sudden. The front tank is one year old, the rear tank is a bout 1.5 months old. Like I say, everything was working perfect until this past Monday morning.

Anything common for this? I'm going to pull the hose off the tank after supper and see what I find. I pulled the outer hose off, it had some gas in it...I'm stumped - maybe the inner hose is collapsed or has a cut in it?

 

The tank that's full has a stuck/leaking check valve in the FDM. It's fairly common, and the only true fix is to change the FDM (not just the pump motor). Click my signature link & look in the EFI Fuel Pump album for plenty of pics & diagrams, including one that shows that valve.

Don't bother messing with the tank until you have the parts to fix it. Just run on the front tank until it's low, then switch to the back for a while, & then to the front again to use the fuel that has leaked into it. Keep doing that (Front, Rear, Front) until you have the time to fix it.

 

Just to confirm, are you saying the front tank is full, or the front tank is empty, and still won't take any fuel?

 

The front tank is empty - there is no fuel leaking from tank to tank. The rear tank is full. I fill my truck every 2 weeks on payday and have never had any issues until this week. I put about 20L in the front tank tonight with a gas can, it took forever. The truck runs just fine on the front tank too.

 

That's what I thought you meant. Unfortunately, I don't have an answer for you, other than this; when I first bought my truck in '96, I found it almost impossible to get the forward tank to take any fuel. No matter how I held the pump handle, it kept shutting off. After a few months of this, I stopped to get gas at a different station, and the front tank took the gas. It wasn't flawless, but I was able to fill it up. Since then, I've discovered that there are gas stations around here whos pump handles just seem to be more sensitive. To this day, I still have that problem at some gas stations, but only with the forward tank.

I'm not saying this is your problem, and I am very curious to see what fixes it for you, but this may be something to consider if you recently started going to a different gas station.

Good luck!

Take care,
~Chris

 

Nah, I always go to the same station just up the road from my house....I'm puzzled too...I guess I'll pull the filler tube this weekend and see what's up with it?

 

Maybe someone was trying to syphon your gas and got the hose stuck?

i don't know, lol, but post your findings!

 

How do you know the front tank is empty? The level senders crap out more often than the shuttle valves.

 

I can tell by the hollow sound coming from the tank when I pressurized it with air...It's about 1/4 full like the gauge is reading. I'm going to pull the filler tube tommorow and see if it's blocked or something. I talked to a buddy at the local Ford dealership - he's kinda puzzled too....He thinks someone put something in my filler neck or the check ball is messed up....We'll find out tommorow I guess....LOL

 

Two possibilities:
1) Some kind of obstruction in the filler neck. Pretty unlikely since the unleaded fuel filler neck doesn't have a big enough hole to allow much of anything to get shoved into it.

2) The fuel vapor return line is crushed or the valve is FUBAR.

 

Don't foget - some of your tank wenting happens through the large outer hose on the filler neck as well. I had a peak at the vapour line, didn't see anything wrong there.

 

My mistake? In a twin tank setup, there should be a single vapor line for both tanks so if the rear tank functions normally, the line would be OK. The return valve though...

The venting at the neck would cease to happen once you got the filler neck full of fluid. The question in my mind is whether a falure of the vapor return valve would slow down the fuel delivery sufficiently to cause the neck to fill.

Have you run a siphon tube down the front neck all the way to the tank? That would determine the presence of a foreign object or a collapsed neck.

 

There's no check valve in that filler neck - it just dumps into the tank. The liquid fuel flows down thru the inner hard plastic tube, and the air escapes between that & the outer galvanized steel tube. The steel is sloped so it can't hold liquid, unless the truck is on a severe side slope.

There's a diagram showing it in that photo album I mentioned in my first post.

 

I'll pull it apart tommorow and let you know what I find.

 

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