So I've made a couple of posts about this, but I wanted to discuss this before I start throwing parts at it.

So back in 2017, I pulled the motor and trans for a rebuild. During this I installed one of Racetronix's hotwire kits to the fuel pump. After getting the motor and everything back in, the car would not accept gas unless I had the pump at the barest trickle. The only thing that would help the issue is if I disconnected the vent line at the fuel pump.

Everyone's go-to with this issue is that the charcoal canister is leaking and charcoal is clogging the lines. So I dropped the tank today to take a look. I've found zero visible issues with the charcoal canister I have. There's no bits leaking out, I don't hear anything rattling around inside, and after inspecting the lines (and blowing air through them) I don't think they're clogged. I ordered a new canister for easy insurance, but is there something else that could possible be causing it that I should look at while I have the tank on the ground?

 

Is your canister purge valve on the intake hooked up??? that could have went bad

Edit: It could also be your Canister Vent Valve thats attached to the charcoal canister... it may be stuck closed

 

The purge solenoid is definitely hooked up. I assumed it was working since the car hasn't thrown any codes. I did at one point disconnect the solenoid while fueling to see if that would allow the tank to breathe and no such luck.

I suppose it's possible the vent valve is stuck. I'll order that as well (thank god for Amazon lol).

Would the rollover valve being stuck cause any kind of issue? Or what I can only assume is another vent (the black round piece in the center of the tank, with one line splitting off to the canister and another to the vent on the fuel pump)? Are either of these replaceable?

 

unless you had the gas tank upside down at some point I doubt it would be the rollover valve

 

Sounds to me like a vent valve issue. I have had a problem, especially in hot weather, with the gas pump continually shutting off while I attempted to fill. Research has led me to believe that my vent valve solenoid is acting up intermittently.

 

My 12’ Silverado does this, if I try to fill with engine running in winter. Turn truck off (like your supposed to) and it fills fine. Have you tried either way?

 

In my truck (04 Av...) it was the vent canister when it did that. They get plugged up with dirt.

 

I'm a tech and see this when the vent valve gets stuck shut. Vent valves are normally open, meaning they get powered shut, but they get stuck sometimes or the filter on them gets clogged. Replace the vent valve and filter if it has an external filter. You'll know if it has an external filter because it will have two hoses to the vent valve. One from the tank and one that goes off and hangs or goes to the body. If it's a single hose going to it the filter is part of the vent valve assembly.

The vent valve is at the tank, the purge valve is at the engine. The purge valve wont affect filling it with gas.

The only other issue would be a restriction in the fuel filler hose, I had a roll over valve go bad on a van once and cause an issue filling it with fuel.

 

I did some research on this when the problem was happening regularly (last summer) and IIRC, accessing the vent valve (solenoid?) required dropping the tank on a 4th gen f-body.

 

Yep. It sucks.

 

Can you access it quicker with a trap door?

 

Most likely yes but you'll have to cut in a different location than where you cut for the pump


Bottom right corner of the pic

 

I dropped the tank once to do a fuel pump. Never again. I decided last summer if it takes me a little longer to fill up because of the shutting off, so be it.

 

LOL I did the same thing. I put a racetronix in mine then later the vent valve acted up. I just put up with it.

 

I'd say dropping the tank wasnt awful. It wasnt fun by any means but it's not the worst thing I've ever had to do in a car.

 

It's not horrible unless you have exhaust that's in the way that doesn't unbolt of come off easily.

Hope that takes care of your problem

 

This is my first post on this forum. I have read all the posts and I will say all are good ways to fix the problem. But I would try taking an air hose and wrapping a towel around it to put positive pressure in the tank to make the vent valve open first. Before you take the tank down. It worked for me so it may work for someone else. Have a good day

 

Sound Logic there I'm glad it worked for you, I discovered my latest car wouldn't take gas Right after I bought it and that was the first thing I tried, unfortunately it didn't work for me. In the process of fixing it right now, charcoal canister and vent valve. Of course everything else under a 20-year-old car is a mess so I'm replacing a lot more than Just those parts, suspension and brakes while I have it all apart.

​​​​​​If you're reading this and you have a stock exhaust on your car you don't need to cut it off and buy a cat back to fix this or if you're exhaust is clamped together with s***** clamps that are going to make even shittier connections when you take it apart and have to put it back together again you should try this.

I know something absolutely amazing most people probably don't know about these cars, though it's described in the oe shop manual

If you have a stock exhaust on your car (One single welded piece from the y-pipe back) you don't have to cut it somewhere near the axle to get the muffler off and out of the way of the fuel tank or even if you have a cat back that's been on there a while and it's all clamped together, now if you have to take that apart to do this you're going to beat the s*** out of it getting The pipes free of each other and off the car and then you're going to have to cram The pipes all back together and clamp them down again and it's never going to be the same so take my advice.

These cars are getting older It just sucks how many nice stainless oem stock exhaust systems have gotten whacked off and thrown away over the years, lots of people would want them to restore their rides or put them back on their modded cars with a cutout for the best of both worlds.

all you need to do to get the exhaust off of your car while only disconnecting it at the y pipe is unbolt the passenger side shock at the top and let it swing down, pull out the passenger side coil spring, and then remove the bolt at the front of the passenger side lower control arm and let that hang down. If you've owned one of these cars for more than a week this should take you about all of 3 minutes to do (Obviously support the rear axle when you do this). Unhook the exhaust at the y, disconnect the hangers, and then yank The exhaust up and out the passenger side wheel well with plenty of clearance hip hip hooray no cuts and your exhaust is still worth something.

Do you have any idea what parts resellers want you to pay them to ship something like an uncut factory cat back across a few states these days?

I'm off my box now have a good day everybody work smarter not harder

 

3 minutes?

You have to pull the back seat and the carpet just to get to the upper part of the shock to unbolt it.

That alone takes quiet a bit of time. The rest is very easy though.

 

There's actually a factory installed cutout in the carpet for quick access to the rear top shock nut. I have the carpet cutouts on my '02 hard top (original owner). Just fold down the back seat and there you go. Photos here from another forum: