I bought an Ls1 Gas tank. I want to use the stock Sending unit and pump on my TPI car. I know I need to switch out the sending unit card, so it reads correctly on my gauges, but other than that, what do I need to do?

The reason I want to use all this stuff is I might be going Ls1 one of these days, and I got a good deal on the tank.

Do I just cap off the Evap and stuff? Will the fuel pump work with my TPI engine? I have an Adjustable FP regulator.

What all is required to use it?

 

WIth the LS1 tank, you'll have to run the LS1 fuel pump assembly that fits in the tank. The sending unit needs modified for the gauges like you said. I think an early 90's grand prix or similar car has the correct part. Lonnies Performance would know, I got my drop in assembly from him.

Fuel lines will need to be run from the tank output to the body hardlines. STock lines will not work. You can run snap cap fittings on the tank plastic output lines to a braided line and then tie that into the hardlines... you'll have to cut and adapt them somehow.
Or possibly get new rubber lines that are longer and run them to the tank and use heavy duty clamps to keep them on.

I ran braided line to the fuel rails and skipped the hardlines so I dont know how to connect them.

Evap stuff... I left the charcoal canister on the tank and just ran the vent line to atmosphere.

 

Will that hold tank pressure, I know for the smog test, they make sure the tank has pressure when they open the gas tank cap.

 

Not sure, but I am pretty sure it does from what I remember. I think when I take the cap off I hear/feel a pressure release.

 

Also, will I have to do anything with the fuel pressure?

So what I have gotten so far is, Swap out the sending unit circuit card, and hook up the tank to the hardlines on the body, and im good to go?

 

Keep fuel pressure at the rail with a regulator like stock TPI. As long as you build a return style system you should be good. I think 98 fbody's were returnless and used an internal regulator in the tank? 99-02 tanks had the return style line so thats what you will need

 

750L98 figured out that if you take the fuel gauge apart and replace the ohm resistors you can retain the LS1 sending unit. Nice to not have to crack open the tank... he has a thread on here on how to do it.

 

It isn't a 98 tank... Can I just block it off so I dont need to use a return line? How hard would it be to make a return line, would I run it off the other end of the Fuel rail or what?

 

I dont know how that would work but stock TPI uses return line, i'd keep it that way.

 

Gotcha. Should be easy if I have to connect it to the hardlines anyway, ill just rig up another for the return. Cool. Thanks for all the help. Does the fuel neck fit in just like the 3rd gen one? And the Straps work too?

I got a 4th gen rear with 3.42 Zexel, and the bigger rear brakes. Figured if I have to drop the tank, may as well put in a newer rear. Only has around 50k miles.

 

straps worked for me, but was a TIGHT fit, i had to really push up to get the bolts started...I may have even purchased longer bolts to get them to work right I dont remember for sure.

Filler neck, i got the 4th gen setup with 4th gen fil cap and rubber neck. I have mine laying in the gas door opening, not bolted to anything. Works fine for me, but you may want to try bolting it to the body where the tab is on the filler neck. 4th gens were bolted to a tab on the body.