Cascade Crew

kjprince · Posted: Sat Apr 23, 2005 10:12 pm Post subject: In-tank pump or not?

Does anyone know if the 83 firebird with the TBI 4 cyl had the fuel pump in the gas tank or somewhere else? If not in the tank where would it be? Also, i am converting over to a carb'b 305 w/mechanical pump and if the electric pump IS in the tank do i have to replace the whole tank or just the top assembly on the tank? where would i get one and do i have to drop the tank to get to it?

Was that enough questions????????

chevymad · Posted: Sun Apr 24, 2005 10:00 am Post subject:

Since you have TBI, it will be in the tank. You can use a fuel pressure regulator and just leave the pump in the tank if you want. Otherwise you should just need to change the sending unit. My 87 is carbed and has both an intank pump and a mechanical pump from the factory. But the intank pump is set to 1psi and just pushes fuel in a loop to the mechanical pump and back.

kjprince · Posted: Sun Apr 24, 2005 1:19 pm Post subject:

so i guess the next obvious question is how do i change the sending unit to only do 1psi? is it a different pump or do i modify the one that is in there? do i have to drop the tank and if so how hard is that? finnaly is there something that i can use to replace the whole pump ass to just have a tube to run to the mech pump on the block. Any links or diagrams would be helpfull if you or anyone has some.

chevymad · Posted: Sun Apr 24, 2005 6:54 pm Post subject:

Couple different ways to go about it. One thats for sure is to buy a fuel pressure regulator.. and just regulate the fuel pressure to 5-7 with it. Then forget about a mechanical pump at all.

Another would be to do something similar to the way my car is. Put a T at the inlet of your mechanical fuel pump. Run the factory supply line and the return lines both to the T and the 3d of course to the pump. You'll need to check the fuel pressure when doing this, to make sure the return line isnt to big a restriction. You dont want more then a couple psi, thus the mechanical pump will boost the pressure to 5-7 you need. This method eliminates vapor lock.

The last method would be to drop the tank and replace the sending unit/pickup assembly with one from an early carb car 82-85. Then just use the mechanical pump alone.

The first 2 methods will require you to use the original oil pressure switch. This supplies voltage to the intank pump. Last method of course doesnt need this.

kjprince · Posted: Sun Apr 24, 2005 7:42 pm Post subject:

since i already have my mech fuel pump just running with the electric is out. I'm thinking that getting a standard assembly from the 82-85 is a good way to go for me. Is it hard to drop the tank on the early third gen's? what is involved in that? do you know if someplace like Baxters' would carry the carb's standard sending unit or would i have to go to a bone yard?

iansane · Posted: Sun Apr 24, 2005 7:58 pm Post subject:

kjprince · Posted: Sun Apr 24, 2005 8:15 pm Post subject:

man i know my best friend's ears are burning right now but.........

how do you drop the rear end??

Is is just removing the top shock bolt (with a jack under the rear end of course) and lower away? also do i need to remove the filler neck or will the whole thing just drop out in one piece?

iansane · Posted: Sun Apr 24, 2005 8:37 pm Post subject:

From what I remember:

The lower control arms and panhard bar can be taken off (or just remove the axleside bolts), the torque arm has to be removed and while supporting the axle you'll remove the nuts on the bottom of the shocks. The brake lines may be the only thing holding you back from dropping it to the ground.

After the straps are disconnected you'll have to twist and manuever the tank to get the filler neck out. The neck is welded to the tank so you can't just disconnect it.

kjprince · Posted: Mon Apr 25, 2005 2:13 pm Post subject:

one thing (and i mean the only thing) nice about my Wife old car (88 honda) was that you could get to the sending unit to replace from an access panel in the bottom of the trunk, kinda wish the firebirds had that but is still sounds pretty easy. i will prob be doing this in about a month or less if i can. now does baxters' just sell a stock replacment for a mech run pump on the engine or do i have to go to a wreaking yard? do you know any direct fit, or as close as possible, aftermarket tanks that are out there in the hard plastic or race style?

iansane · Posted: Tue Apr 26, 2005 12:47 am Post subject:

I don't know anything about mechanical pumps and such, sorry. Sad

I just slapped a walbro intank unit in my car and called it a day. Although mine's not carb'd.

Most cars I've seen have that access panel. Sucks fbods don't.