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4th gen tank, slow to put in fuel

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Old Feb 2, 2015 | 06:06 PM
  #1  
WTR388's Avatar
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From: Atlantic Canada
Car: 87 Trans Am
Engine: LS1
Transmission: T56
4th gen tank, slow to put in fuel

The last time I filled it up (about 4 months ago), it took me about 10 minutes to do so, I just couldn't add fuel very fast without it flowing up the neck.

When I did my tank install, I cut off the 3rd gen filler neck, and essentially clamped a hose over that and the other end on the 4th gen tank (maybe 6-8" of hose between the two).

My only thought, is that I didn't extend the vent line that is on the inside of the 3rd gen filler neck down in to the tank, and it's just building up air pressure, and once it "burps" I can add more fuel until it needs to burp again.

Whats the trick?
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Old Feb 2, 2015 | 07:07 PM
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Re: 4th gen tank, slow to put in fuel

The 4th gen filler neck doesn't have a vent, so I doubt you need one.

I shortened the 4th gen neck & made a bracket to hold it in place.

Did you leave the charcoal canister on top the tank in place? It should vent the tank.

I can fill mine full speed.
Once it clicks off, it is full & wont take but a quart more.
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Old Feb 2, 2015 | 09:43 PM
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From: Atlantic Canada
Car: 87 Trans Am
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Re: 4th gen tank, slow to put in fuel

I left everything on the tank intact. Maybe there is something about the angle of my hose. Guess I'll play with it once it's car season.
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Old Feb 3, 2015 | 09:24 AM
  #4  
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From: North Salt Lake
Car: '86 Camaro, '94 Camaro, 3 others
Engine: LG4 ->L29, L32->LR4, L36, LG4, L31
Transmission: 700R-4, T5WC, 4L80E, SM465, 4L60E
Axle/Gears: 3.42, 3.23, WTB/WTT 2.93
Re: 4th gen tank, slow to put in fuel

This is common for many '00s GM vehicles, and it is because of emissions. They're trying to catch all the gas fumes, so the tank vents through the charcoal canister. Only the '00s GM canisters flow air through them slower to be more effective.
I'm guessing you're using an '01-'02 Camaro "evaporative" (charcoal) canister, it's a rectangular plastic box atop the tank.
Just more OBD2 junk that's a cheap execution of a green idea.
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Old Feb 3, 2015 | 04:17 PM
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Re: 4th gen tank, slow to put in fuel

Yep, tank is from an 02 T/A. I left the charcoal canister on top of the tank as I have heard complaints of gas fumes without it... Maybe I'll pull the tank out, pull the canister off and attach a hose with some form of air filter so it's free to vent.
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Old Feb 5, 2015 | 07:09 PM
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Re: 4th gen tank, slow to put in fuel

I left the charcoal canister on mine & ran the vent hose from it up near the filler neck.


Never got any fumes & I can fill it with no problems.
Mine is an 02 tank.
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Old Feb 6, 2015 | 08:17 AM
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Re: 4th gen tank, slow to put in fuel

I also used the 4th gen filler neck...just shortened the rubber hose. I left all of the parts on the tank, and just left the holes for the EVAP system loose. It hangs down by the fuel filter area. I never smell raw gas fumes, and the tank fills as fast as I can pump.

Something must be blocked up or something. Was your tank sitting with the lines exposed for a period of time? Outside or anything?

Justin
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Old Feb 9, 2015 | 10:14 PM
  #8  
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From: Atlantic Canada
Car: 87 Trans Am
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Re: 4th gen tank, slow to put in fuel

Thanks guys. Once it gets a few degrees warmer I'll double check my angle of the filler hose, if it dips down at all before it goes in to the tank (too much filler hose) it might cause enough of a restriction... If that isn't it, then I'll pull the tank down when it gets empty and pull that vent line off.

The tank came from the donor car and then sat in my garage for 8 months. I've only filled the tank once, drove it about 6 miles and then I put it away before I had to leave for work.

It's really embarrassing taking 15 minutes to fill it up lol.
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Old Feb 10, 2015 | 11:55 AM
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Re: 4th gen tank, slow to put in fuel

If it was sitting with the lines disconnected, outside, for a while...you'll be surprised what can make little homes inside of the hoses. What are those...wasps? They make little mud plugs inside of things like hoses and all. I remember I had a piece of braided line that ended up with 3 or 4 of those things in it and it was only a 12" piece of hose haha.
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Old Feb 10, 2015 | 12:20 PM
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Re: 4th gen tank, slow to put in fuel

Dirt daubers, and yes, they seem to love fuel and vent lines.
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Old Feb 10, 2015 | 02:35 PM
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Re: 4th gen tank, slow to put in fuel

Originally Posted by ghettocruiser
I also used the 4th gen filler neck...just shortened the rubber hose. I left all of the parts on the tank, and just left the holes for the EVAP system loose. It hangs down by the fuel filter area. I never smell raw gas fumes, and the tank fills as fast as I can pump.

Something must be blocked up or something. Was your tank sitting with the lines exposed for a period of time? Outside or anything?

Justin
Hi Justin, I'm getting ready to install a 02 T/A tank in my 83 Camaro (putting LT1 in it). Don't you need to run a vacuum line to the intake manifold to burn fuel fumes collected in the canister? I thought you had to let the ECM control the purge valve. If I don't have to do that my job just got easier.
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Old Feb 16, 2015 | 12:08 PM
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Transmission: Built T56
Axle/Gears: Strange 12-bolt w/ 3.73
Re: 4th gen tank, slow to put in fuel

Many of use leave the vent line disconnected. Some put a small filter on it, but anything coming out of there has already been through the charcoal canister. So Im not sure how much good its doing for the fumes. I never smell raw fumes near my car...except for what comes out of the tail pipes haha.

The PCM can control the EVAP system..yes. But forget about using the fuel tank's factory sender for controlling a fuel level gauge, because you cant have both at the same time.

IF you dont need it to get your car on the road "legally"...then just leave the line off, and you should be ok.

Justin
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Old Mar 4, 2015 | 10:49 AM
  #13  
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From: Wylie Tx
Car: 1989 RS,
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Re: 4th gen tank, slow to put in fuel

I had the same problem on my '99 Camaro. The anti cyphen valve inside the tank caused the problem. Common failure with the plastic tanks. After trying to clean the valve and spring, I ended up removing it and getting a locking gas cap.
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