Hi everyone...first time poster here.
I just bought a 96...very clean...very nice truck but it has one problem.
When I bought it both tanks were empty...it was running off the back tank.
I went to a gas station to fill up and I couldn't get any gas in the front tank...in fact gas was flowing out of it like it was over full. I filled the back tank and left. As I was driving I switched to the front tank and it registers empty and the truck stalls out. It drives fine on the back tank but I would like to get this fixed. Does anyone have any ideas as to what is going on and how to fix it?
Thanks Keith

 

Could be full and have a bad sender/fuel pump. Only way to know is to pull the tank. Set to the front tank and notice if you can hear the pump run when turning the key to on. Or try to see if you can syphon fuel out.

Welcome to the forums too.

Adrianspeeder

 

If you're sure the tank is empty, then the reason that it won't run on the front tank is lack of fuel. Run the front tank KOEO test that adrianspeeder recommended and check for fuel pressure at the Schrader valve. If there's no pressure,then either the pump is toast or there's no fuel. If you can hear the front pump running, there's a 99% chance it's OK. In that case the problem is most likely the front tank vent tube line is blocked, plugged or pinched. That would prevent the air in the tank from flowing out and therefore prevent gas from flowing in (or out).

The vent tube runs from the top of the tank to the inside of left frame rail, crosses over to the inside of the right framerail and runs forward to the carbon cannister. Since you're not having a problem with the rear tank, the most obvious place for the blockage is before the line reaches the frame rail. This could be a blockage in the tank or it could be a blockage in the line. There's no easy way to find it.

 

Thanks for the advice!!
Here is a twist to the story.
I was just out running around and I thought what the heck and I switched over to the front tank...and it ran...it still reads empty..but I drove it on the front tank for about a half hour.
Yesterday when I would try to switch to the front tank it would stall out within seconds.
What do you think??
Thanks Keith

 

I bet my lunch money on a sender/fuel pump problem. None of my broncos have working gas gauges as all the senders are bad so don't worry bout the gauge yet. See how long you can go on the front tank milage wise. If i remember correctly it is 18 gallons.

Adrianspeeder

 

Or it could be a float. In my 95 with dual tanks, I had to replace the pump, but I also have the "reading empty" problem. I know how to fix it, but I don't wanna buy a whole new sender. I know it's the float because the last time I pulled the assembly, the float was full of gas!!

 

Yup sender/fuel pump.

 

It's been a couple days now and she is still running on the front tank.
It still doesn't register any fuel on the guage but I can live with that.
The check engine light came on yesterday.
When running on the front tank I get a sputter now and then...so I figure it is registering misses.
I'll have to get it checked and reset...those lit up words drive me nuts.
So....if it is a sender\pump problem can I keep driving on it until it goes or is it one of those things that I should do something about before it screws something else up?
Thanks Keith

 

Well, if the pump is indeed going...which it sounds like it is...I'd get it replaced along with your plugs. They are likely fouled. If you are gonna do it yourself, when you get the assembly out, check the float and see if it's full. If it is, you might just need to replace that instead of the whole sender...although, I've had a hard time finding just a float and you can't really replace them....so in order to be totally safe, replace it all!! LOL!
You can keep driving for a short time I think, but I'd try to get it done soon. I don't think it'll screw anything else up, if you only drive it a short while, other than the plugs.

 

First go to autozone and just pull the codes for free. We'll see whats goin on there.

The beauty of these dual tank trucks is you have a backup. I wouldn't worry bout it till you wanna take the time to drop the tank. Plugs arn't a big deal to change on these engines so you have a very low worries issue.

By the way, post the other stats of the truck. I always love the old iron...

Adrianspeeder

 

I had the same exact problem with my 1996 f150. I fixed several things. First the tank switch had corroded contacts so I cleaned them and the gauge, and tank switching started working. The previous owner stopped using the front tank because of this. Then, when trying to fill it it kept backing up like it was full. Soneone at one time removed the front tank and replaced the filler tube, but cut the inside filler tube to make it easier to get back together. Therefore I couldn't fill the tank. So I cut a wash machine hose to fit and replaced the inner tube. The truck missed a little after that and I figured the pump, etc., was all gummed up. Put in seafoam. Needed to change the filter right away cause all the gunk clogged it up. Had to take the tank off and fix the pump and stuff cause the gunk clogged it all up. All in all it wasn't that bad of a repair. My wife is now calling me the fix-meister.

 

I went over to autozone and it read that the gas was too lean...so I am going to stick with the back tank until I can get the front one fixed.
How much money am I looking at to get it fixed?
As far as stats on my truck...it's pretty barebones.
It's white, short bed, reg cab, 2x4, 5 speed, 4.9 inline 6, bigger tires, 90K miles, tinted glass, not too many extras. It has a good look to it and it looks like it just came out of the showroom...really clean.

 

OK...I hate to keep beating this subject but...
I put a couple cans of HEAT in the front tank...thought maybe it had water in it since it said at autozone that it was running lean...and it is running smooth.
I went to put some fuel in it this morning and it won't take any.
It shuts the pump off as soon as you trigger it.
I think I got .64 cents worth of gas in it before it started running out.
I know it's not full because I have driven on it for a few days now.
Any ideas?
Thanks Keith

 

As Strangeranger stated you probly have a plugged air breather line or an obstrution in the filler tube. use a drain snake or some thing else stiff long & flexible ,( wire coat hanger) and try to check for an obstuctionin the filler tube. If theres no obstuction in the filler tube (unlikely) then get on your back and find the air vent tube (it should be rubber) and trace it to the "T" where it meets the vent for the rear tank, (pass side just behind cab on frame rail). Disconnect it there and try to blow air through it (Make sure gas cap is open). If air will not pass then remove the rubber hose from the tank side and try again. If air still will not pass then replace the hose. Other wise the vent is plugged in the tank and you will need to drop the tank to clear it.
Hope this helps.