Should i fix the TBI or go to carb? And what's this wire?

[Redfish]

You have a reliable pump and return system with the factory TBI stuff, use it. Put a bypass regulator up front for 4 psi or whatever is needed on your carb, return through the stock return line, and you're set. Worst case when you remove the computer etc, you may need to run a new ignition wire to the fuel pump relay. I can't remember on this setup, but if the fuel pump relay circuit goes through an oil pressure switch, I'd keep it there, good safety margin.

The original TBI does use an oil pressure switch as part of the electric fuel pump circuit but it is only a backup. It is there to allow the engine to get fuel even if the primary circuit fails.

 

[bucket]

The original TBI does use an oil pressure switch as part of the electric fuel pump circuit but it is only a backup. It is there to allow the engine to get fuel even if the primary circuit fails.

As long as the carb bowls don't go dry, the oil switch method should work fine for startup. In theory anyway.

 

[Redfish]

As long as the carb bowls don't go dry, the oil switch method should work fine for startup. In theory anyway.

I would suspect that it may take a little longer to start. The starter would have to spin the engine long enough to build enough oil pressure to make the switch contacts close. I honestly don't know what that pressure is.

When I turn the key to "On" I can hear the fuel pump run, I let it build pressure and cut off before I turn the key to "start". Using just the oil pressure switch would eliminate the ability to let the fuel system pressure up ahead of time.

 

[bucket]

I would suspect that it may take a little longer to start. The starter would have to spin the engine long enough to build enough oil pressure to make the switch contacts close. I honestly don't know what that pressure is.

When I turn the key to "On" I can hear the fuel pump run, I let it build pressure and cut off before I turn the key to "start". Using just the oil pressure switch would eliminate the ability to let the fuel system pressure up ahead of time.

Right, but the carb bowls would (should) still have a supply of fuel in them to feed the engine for a short time.

 

[bucket]

Oh, I believe the stock switch closes around 9 psi.

 

[wanderinthru]

Right, but the carb bowls would (should) still have a supply of fuel in them to feed the engine for a short time.

With todays gas, the bowl will prob be boiled dry. Can't see where he put an insulator under the carb. The pump does run with out cranking, building oil pressure right?

 

[AyWoSch Motors]

Okay, so this was plan...

Stocl style carbureted sending unit, check valve, fuel filter, inline precision brand 2-8 psi fuel pump... carb.

Have a switch in the cab with an inline fuse, heading straight to the pump. As soon as i start cranking the engine over, turn on the pump..
Any issues with that?

I had planned the same style thing, but with the intank pump, but it no longer works.
Im not spending $150 on a new intank pump just to have it die in 2 minutes like the old one. And i hate having to pull the fuel lines and pull the whole sending unit out everytime, just to change a pump.

 

[AyWoSch Motors]

This is what i had setup already...

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[wanderinthru]

Okay, so this was plan...

Stocl style carbureted sending unit, check valve, fuel filter, inline precision brand 2-8 psi fuel pump... carb.

Have a switch in the cab with an inline fuse, heading straight to the pump. As soon as i start cranking the engine over, turn on the pump..
Any issues with that?

I had planned the same style thing, but with the intank pump, but it no longer works.
Im not spending $150 on a new intank pump just to have it die in 2 minutes like the old one. And i hate having to pull the fuel lines and pull the whole sending unit out everytime, just to change a pump.

Dont see why you couldn't turn the pump on first, or switch it off run on the key switch.

Just carry a couple extra pumps behind the seat.

 

[AuroraGirl]

Pump that was in it crapped the bed.

so... you removed it then.. and put a non EFI sender in ? I hope so lol..

 

[AuroraGirl]

This is what i had setup already...

You must be registered for see images attach

that poor pump is probably not going to like pulling gas up a short distance, through a check valve, then a filter then push it all the way to the front to the carb.then a regulator
You may consider switching the pump to the back and then that way the check valve maintains a prime on the pump and the pump is only doing its short lift and then push the rest of the way

 

[Ricko1966]

You can use your factory tbi wiring for your pump. I wouldn't use the check valve,you want the pump after the filter to keep crap out of your pump. At the front you are still going to need a bypass regulator like the holley I put up,for your return,so you don't dead head the pump. You could get away with a wix 30041 filter in front instead of the regulator.

 

[AyWoSch Motors]

that poor pump is probably not going to like pulling gas up a short distance, through a check valve, then a filter then push it all the way to the front to the carb.then a regulator
You may consider switching the pump to the back and then that way the check valve maintains a prime on the pump and the pump is only doing its short lift and then push the rest of the way

You can use your factory tbi wiring for your pump. I wouldn't use the check valve,you want the pump after the filter to keep crap out of your pump. At the front you are still going to need a bypass regulator like the holley I put up,for your return,so you don't dead head the pump. You could get away with a wix 30041 filter in front instead of the regulator.

You must be registered for see images attach

I figured the amount of fuel from the check valve, to and in the filter, and to the pump, would be a reservoir/buffer, so the pump wont run dry. By the time its sucked the line and filter dry, it will alread be pulling from the tank, which will be about 1 foot away. This is all going sit on the frame rail right above the tank. Ibe been told the closer you can get the pump to the tank, the better, because electric pump like to push more than pull.
And you want the filter before the pump, so the pump wont get crap in it, and you want the check valve before the pump so that it can't backdrain to the pump letting it run dry.
Correct? Thas what ive learned to be right from my research.

 

[AyWoSch Motors]

so... you removed it then.. and put a non EFI sender in ? I hope so lol..

Thats why i said before i put a "CARBURETED SENDER UNIT" in it.
Non EFI, no pump, fuel pickup goes to bottom of tank uninterrupted.

 

[AuroraGirl]

Thats why i said before i put a "CARBURETED SENDER UNIT" in it.
Non EFI, no pump, fuel pickup goes to bottom of tank uninterrupted.

;( I didnt see that line, I was just making sure.
and I see your logic on the fuel check valve, whats your part number of your pump again? I will do a deep dive and ensure it wouldnt be an issue. I understand the logic of the filter, ricko @Ricko1966 but thats a lot of resistance to get fuel to the pump let alone push it the rest of the way. it needs to be a high flo kind of thing, like a sock on a sending unit(which is new)
I would not restrict it much further since it is also pulling through a check valve, which shouldnt be too bad if the pump doesnt have one itself