Can’t fill up tank?

Hey guys, hoping for some advice/experience with an issue I’m having. Dealing with an 04 prerunner with the 2.7L. Owned her for 7 years, have 302,500 miles on her, 140,000 of them mine. Day that I took her home I filled the tank to the brim, not knowing any better. Been getting P0441, P0442, and P0446 codes ever since so I guess I fried the evap canister. I’ve just kept the code reader plugged in and cleared the three codes every two days, never been an issue besides being an annoying reminder not to top off your tank. Fast forward 6 years and change, I’ve started to have two issues. Issue 1 is getting the tank filled, which has gotten to the point now where I can’t put more than 3 gallons before the pump clicks off. Once it happens the pump only runs in one second intervals before clicking off. Issue 2 goes hand in hand with issue 1 without fail. When I try to start the truck after filling up as much as I can, it will start and immediately dies. Acts like it’s flooded. I figured out pretty quickly that if I give just a wee bit of pedal it will start almost normal. On the times that I’ve had it die, I’ve been able to get it started with that method, and it runs rough for less then a second before clearing up and runs fine otherwise. I’ve had maybe three random times where it filled up all the way and started normal, the only thing I can think of that those issues had in common was being completely empty. But I’ve been empty other times and had it happen so I don’t know. From what I’ve read some people have had issues with the fill tube vent being blocked, but I would think that would be a consistent issue with it shutting off at the same point every time? Other one I’ve heard is the little spring loaded door at the base of the fill tube where it meets the tank and stops fuel dumping if the truck rolls can get gummed up and cause the fill tube to overflow into the evap canister? This one kind of makes sense to me with the starting issue. I’d like to fix this and get rid of those codes as well, so if I have to replace a component on the canister or the canister as a whole I’d like to bite the bullet and be done with it. I haven’t gotten around to trying to fix it before because I don’t have a whole lot of free time lately. That being said, my first kid is due in December and I’d like to kick this issue while I still have what little free time I do have. Thanks in advance for y’all’s input!

 

So I have a somewhat similar issue. Mine popped up out of the blue a few months back. I had about 1/4 tank of gas, so I went to fill up. I managed to pump just a few gallons, and the pump clicked off. I drove to another gas station and the same thing happened (did this to rule out a defective pump).

My Tacoma isn't my daily driver, and I ruptured my Achilles on my right leg 2 months ago, so I just got cleared to drive it (it's a 5spd, so can't drive it with just one leg). So, being excited to drive it again, I decided to go for a quick off-road trip this past Saturday. I managed to pump 13 gallons into it before leaving, no problem.

I got pretty far out this trail and started noticing a strong gasoline smell. I pulled over, turned off the engine and opened the fuel cap and it made a loud hissing noise for the next couple minutes, and I could visually see lots of fuel vapor gushing out. So clearly my tank is building excessive pressure.

I took the bed off yesterday and over the next week I plan to replace the fuel tank check valve (probably not the exact proper terminology). That part looks like this:


While I'm in there I'll also do the charcoal canister, fuel pump/sock and fuel pump sending unit. My understanding is that it's either going to be the check valve or charcoal canister responsible for the issues you and I are experiencing. But I've never had a code thrown or any rough starts, rough running symptoms from mine.

I can get you the part numbers for the charcoal canister and the check valve later today (I've already got new OEM ones in the garage), when I get home.

 

Heard another member call it a rollover valve. So you’re planning on replacing the entire charcoal canister? I’m wondering if there is a sensor that has gone bad or a valve/hose that is blocked where you could either fix or replace just that part without doing the whole canister. How much did you get yours for and where from?

 

I need to do my fuel filter and change some fluids so maybe that can get added to my list for the weekend.

 

I paid $258 for the charcoal canister and $116 for the roller valve (apparently Toyota calls that the "Valve Assy, Fuel Tank").

Yea I'm just going to replace the whole charcoal canister and the roller valve both. Got both from my local Toyota dealer. I pulled the parts up on Ourisman Toyota Parts website and my dealer price matched them. Got $200 of their list price for the charcoal canister.

 

What was wrong with your roller valve, was it falling apart, broken, sticking…etc?

 

Not sure yet, because I haven't pulled the old one.

For now the truck looks like this:



I hope to find time tomorrow to get the work done and swap out the charcoal canister and roller valve (and want to do the fuel pump and sending unit as "while I'm in there items"). I'll keep this thread updated as to whether or not it solves my over-pressurized fuel tank problem.

 

Ah understood. How difficult was it to remove the bed, need anything beyond normal garage tools? And could it be shifted out of the way or does it need to come all the way off?

 

I like your wheels/tires. Cool looking truck!

 

Bed removal is pretty easy all in all. There's 6 total bed bolts (3 per side) that have to be removed. I used my impact gun but I'm sure you could get them with a simple ratchet, but if rust is involved (I'm in Northern AZ, so no rust on mine), they could be a bear.

Then you'll also need to disconnect an electrical connector behind each tail light lens (remove the lens and you'll see it). That will allow you to fish the wiring out of the back of the tailight housing and just drape it over the frame (you can see mine dangling in the picture).

Lastly you'll want to unscrew 4 screws holding the black plastic flange around the filler neck, and just pop that thing off. Then the bed can be lifted off, but be careful to not disturb the filler neck as you do.

I'd recommend just removing the bed entirely for overall easier access to the top of the fuel tank. While you could prop it up like a dump bed, I could see that being unsafe and should it fall it could hurt you or crack your filler neck off. Just not worth either risk.

 

Thanks! I like the look of my wheels, but they've got too little backspacing and require wheel spacers to not rub the calipers. So ultimately they're going to need replacing. Your wheels look good too

 

By the way just realized something. You may want to climb under your truck and determine exactly where the fuel tank sits in relation to where your cab ends and bed begins.

Being a double cab, vs. mine being an extended cab, you might actually have an access panel under the rear driver side seat that goes down to the fuel tank. I know that's how 3rd Gen 4Runners are and you may not have to remove the bed at all. That is unless you end up doing the charcoal canister, as that should sit to the rear of the fuel tank (you can confirm that from underneath though).

 

Charcoal canister is for sure going to need the bed removed, or have arms like an octopus to get to it. Not sure about the tank, but I’m thinking it will also be beneath the bed.

 

Most common causes are a stuck closed evap valve, clogged vent, or a saturated evap canister. You can test the valve by giving it 12v and listening/feeling the click of the solenoid opening and I'd start there because it's usually the culprit of a P0446. Make sure your electrical is sound before chasing a leak... bad valves can pop a false leak code because the leakdown test doesn't run properly.

 

Evap valve possible to get to/test without pulling the bed?

 

Yea @velogeek, please clarify where this evap valve is that I can apply 12v to?

 

Should be on or near the canister and you should be able to reach from underneath. You'll see either an integrated filter or a hose attached that goes to a filter nearby for the vent and that could be clogged as well... if the solenoid works so not the worst idea to blow through it from the canister side as you actuate it.

There's a purge valve that should be on the side of the engine as well but typically the gas fill shutoff is from the vent valve at the canister.

With a 2004 you're probably looking at an assembly now so if you do need to replace it, it's probably canister and all.

 

Okay I'll check for that. My bed's off now, so should make it easy

 

Pics would be great, especially if I try and do it without pulling the bed. Good luck!