Going from TPI to carb. Have a fuel question

[Firebird_TA]

Okay, I am going from a tuned port injection setup to a carb.  I have added a mechanical pump to the engine.  Is it possible to leave the electric pump in the tank and use the mechanical pump(disconnect power to in tank pump, just leaving the pump in the tank and using the mechanical pump to pull fuel).  Let me just ask my question the clear way, does the in tank pump have a device that would stop me from getting fuel via a mechanical pump or not?  I am unable to remove the tank, so I am hoping to be okay without removing the tank.  If nothing else, I am using a mech. pump with no return line, so I am assuming that it has a built in regulator, will it stop the fuel from flooding out my carb?

[dumbucket1]

when I used to put v8's into s10 trucks I would just leave the electric fuel pump in the tank and never had any issues with using the mechanical pump.

Again never had a problem with flooding either.

[Blazin]

Why not use the electric pump and just put a regulator in line?
I know a guy that pulled fuel through an electric pump on his 87 Elcamino when he went to a SB 400 from  4.3. He could never get it to run quite right had fuel starving issues. He ended up going the regulated electric pump route and it solved his problem.

[Firebird_TA]

when I used to put v8's into s10 trucks I would just leave the electric fuel pump in the tank and never had any issues with using the mechanical pump.

Again never had a problem with flooding either.

So, in theory then, since I did more checking and both the TPI and TBI engines use the same pump in the tank, I should therefore be able to just leave the electric pump wired up as is and just run the lines to the mechanical pump and then to the carb?  I could run the regulator, but cash and location are against me at this time.

[dumbucket1]

I didn't have any problems and I did 4 s10's this way but your results may vary.

[red4wd]

The only experience I have had is with a theft recovery IROC.  We could not find a tuned port engine and replaced it with a carb engine.  It would run with the fuel pump in the tank but would not pull enough gas through the pump to feed the engine on the top end.  We ended up pulling the tank and removing the fuel pump.

[Blazin]

My buddy got rid of the mechanical pump and ran the lines right to the regulator. Put a block off plate in place of the pump.

[Firebird_TA]

Tried running the lines to my mechanical pump... started right up... then completely filled the intake manifold and cylinders with gasoline .  So, after removing all eight plugs and watching about a gallon of gas fall on the ground, I switched my approach.  My fuel return line runs to the bottom of the tank... it is now my feed line for my mechanical pump.

[Captkaos]

Did you disconnect the power to the pump?

[DnStClr]

Yes, it sounds like both pumps are supplying fuel. I always thought that the tpi engine had to have @ 15lbs fuel pressure to supply the intake, but it appears that your supply is much too rich.

[Firebird_TA]

When I cut power to the pump, the mechanical pump was unable to pull fuel from the tank.  That is why I am feeding from the return line now.

[F-body Demon]

I agree with some of the first posts. Just run a regulator.