CALI CAMARO

Is there suppose to be a rubber sleve over the filler neck where it meets the gas tank?or how does it seal?

rgarcia63

Well since you didn't give any info on which model you have; My '88 filler neck is soldered to the gas tank.

Do you suspect a leak?

lizardkng

My fuel tank has no rubber visible on the exterior, anywhere, including the filler neck.

CALI CAMARO

Sorry I always forget!I have a 89 camaro5.0 tbi.I drooped the tank because i had a gas leak and the filler neck doesnt look like it fits snug in there.too much play,I think.but then again I'm no expert.

rgarcia63

When does it leak - when it's full?
If the pump has been replaced, the leak maybe from around the rubber O-ring seal where the fuel lines enter the top of the tank, or it could just be a faulty pressure relief valve.
Depending on how much pressure in addition to the weight of the gasoline (15 gallons is about 100lbs) was applied when you drooped the tank, the filler neck may have cracked where it meets the tank - you may now have another leak. The tank is designed to hold vacuum. You should hear the vacuum release when you remove the gas cap.

Any leak that will allow air to enter the tank will intruduce moisture as well, and will cause the tank to rust.
My daughter's boyfriend got a good deal on a used BMW with some minor problems, but once the the tank was filled full it leaked, removing the tank showed it to have cracks around the filler neck and 50% rusted on the inside which was the root cause of those "minor problems."
He has cleaned it out, and welded the cracks, until he can get a new tank, sending unit, and fuel pump.
The complete fuel system has to be cleaned and the fuel injectors refurbished, or replaced as rust and varnish forming from the moisture has begun to clog the system.

I also had to do the same for my '88 when I found a leak at the filler neck, and much to the admonishment of some TGO members, I installed an access door above the tank, and modified the fuel lines to allow removal of the fuel pump from above.

CALI CAMARO

Thanks for the reply's

5678TA

if you wanna make sure the filler neck does not leak, slap some JB Weld where it meets the tank and you are good to go..

CALI CAMARO

It had jb on it when i brought it down.and it was falling off

rgarcia63

If it hasn't started to rust and there's no damage to the filler neck, or the tank filler neck entrance, then you still have chance to salvage it.
Take it to a radiator shop and have them solder the filler neck back on, that's how it was originally attached. Welding would burn off the protective internal coating.
The JB weld probably broke because they didn't get the filler neck at the correct angle, and or it waan't allow enough time to properly cure.
One reason the solder cracks is because there's no support on the filling end of the neck, and some people have a tendency to lean on the gas nozzle while filling.

5678TA

bad surface prep? not enough time to dry?

CALI CAMARO

it has no rust on it.it look like it was bad prep.if i have the filler neck solder on how would i get it back on the car.im kinda new at this.

rgarcia63

Check the interior for rust now that you have it out, the gauge sending unit is the first that'll rust. Replace the fuel pump sock filter as well.
With the filler neck on solid you'll have to angle it so that neck goes over the frame while the passenger side hangs down.

Hope some of the members have it taken pictures of their installs that they can post to help you out.

The pump must be completely submerged before starting the engine.

CALI CAMARO

The tank was a lil bit past half way. where would the pressure relif valve be.

rgarcia63

It would be in the engine bay on your '89
From what you've posted I don't think you have any holes in the tank, the sloshing (at half full) of the fuel would reach the loose filler neck and leak out. With that leak there wouldn't be enough vapor pressure for the vapor recovery system to function properly, and MPG would suffer.

GM TSB: Some 1988 Camaro models with V-8 engines (RPO L03, LB9 or L98) may exhibit a "whining/whistling" type noise coming from the rear of the vehicle. This condition is most apparent when the engine is shut down after extended city stop and go driving, or operation at high ambient temperatures.

To eliminate the possibility of this occurring, an interim production change to the evaporative emission control system (EECS) was implemented on January 29, 1988.

The VIN breakpoint for this change is noted below:

Camaro - JL145359

This change terminated usage of an in-tank pressure control valve which was part of the fuel tank sender assembly, and initiated usage of an underhood externally mounted tank pressure control valve.

Service fuel tank sender assemblies available from GMSPO are of the second design configuration without the in-tank pressure control valve feature. When replacement of a fuel tank sender assembly is required on vehicles assembled prior to the above indicated breakpoints, it will be necessary to install a fuel tank pressure control valve kit, P/N 10113082, in the existing hose assembly connecting the vapor carbon canister to the evaporative emission chassis pipe.
The instructions for this installation are included in the applicable fuel tank sender assembly service kits indicated below by engine RPO.

There also what's called a remote tank pressure/vacuum relief valve that's located over the rear axle on a bracket on the driver's side.
Item #7 in this diagram.