Fuel Pump Retrofit

anybody run an in tank pump after going TBI?

Not looking to reinvent the wheel..

 

Yup. Went to NAPA and got a unit for a 91 GM. Had to cut the pickup tube offf to fit.. Added a insulated post for the feed wire.... More later when I get on a desk top

 

awesome thanks..
i figured that was the way to go...

I have been experiencing some cavitation and vapor lock, even after I properly vented and purged my tank.

My fuel pump is just not in a good spot... and there really isn't a better spot other than in the tank.
fuel lines come close to exhaust as well... going to try insulation before I drive myself nuts.

 

dont forget some kind of baffle in the tank,i used a baffled yj tank in the boys 70 took the in tank pump out and fitted a non efi sender.

 

I also had some stalling problems especially at higher altitudes until I converted from in line to in tank pump. I just took the stock sending unit and shortened the pick up tube. Using submersible fuel line and hose clamps I then attached a TBI pump to the shortened pick up tube. Attached the sock filter to the intake side of the pump with hose and clamps so the sock filter was in the same position at the bottom of the tank as its stock location. Works perfectly with no more stalling issues.

 

There are several different aftermarket solutions out there. Here is a link to one of them. Just Google "Retrofit in-tank fuel pump".

In-Tank Fuel Pump Module - PA-Series

 

This is similar to what I got at NAPA.. Can't remember how much I paid though.. I found a plastic fitting [Ace Hardware] and installed it in the access cover next to the outlet tube.. I also used a sealer [Seal All] on it to keep it from leaking. I installed a small brass machine screw [6-32] in the fitting using a nut on the outside and secured the pump feed wire on the inside under the screw head with a ring tongue, I drilled the bracket for the gas gauge arm and threaded it, for a ground. Someone above outlined what he did and that is pretty much how I did it.. I use small hose clamps to add a stiffener to keep the pump in place Bend it to fit, clamped to the outlet tube and also around the pump. No baffle here, and no problems in 2 years of running..

MasterPro Fuel Pumps MPE16007 - Electric Fuel Pump | O'Reilly Auto Parts

 

You can put the high-pressure pump under the hood or near the front of the car, and use the original mechanical pump for fuel delivery to an accumulator. This diagram shows a second low-pressure electric pump, but a mechanical pump would work just as well.



High Pressure Fuel System on a 65 EFI Fastback

This thread shows another implementation of such a system - Megasquirt2 Install AMC360 TBI 83' Cherokee - Page 2 - International Full Size Jeep Association

It's more complicated, and it introduces another failure point (a second fuel pump) into the system, but it has some advantages. You don't need any additional baffles or surge tanks in the system, since the fuel filter / accumulator takes care of that. The canister filter acts as a sediment bowl to remove dirt and water, and no other fuel filters are needed. Name-brand mechanical fuel pumps are very reliable, and are engineered to bring fuel from your factory fuel tank and lines efficiently and reliably. You could even run the EFI system from gravity feed if the mechanical pump fails. All the parts are exposed for easy testing and service.

 

One thing to keep in mind. If you are using a 90's GM TBI you need ~ 12psi in and <4 psi out.. I tried using the OEM mechanical pump to push to the electric under the hood.. I had vapor lock problems more than once. Thus into the tank I went.

 

yeah, I'm not looking for another failure item... 1 electric pump is more than enough
I went in tank with my YJ (also a Howell setup) but it was almost a drop in since the YJ tank came with FI....

Seems the way to go is modifying the sending unit to accept an in tank pump..

 

As i remember telling you, the pump is not lower than you fuel tank. I have a tbi set-up on my jeep and never had issues with my pump located lower than the tank. Inline pump are pusher so they need to be lower than the tank, simple as that. I would give it a try before buying a new pump

Here what i found in holley site:

8.3 Fuel Pump Installation
1. Do not mount the fuel pump higher than the lowest point of the fuel tank.

 

100% you earned the "I told you so" moment...

also what the picture doesn't show is how close the exhaust is to all that...
between the bare aluminum, exhaust, and road heat the temps under there were significantly higher than any other area on the truck. Only seems to be having an issue above 70 deg and prolonged periods of 2K RPM.. according to Howell "textbook cavitation due to heat"

Exhaust runs driver side, as does fuel lines..
to move the pump it would move it closer to the exhaust unless I move it to the passenger side.
If I do that I will be needing to re run fuel lines..

I'm curious to know where you mounted your pump.. if for nothing else to see if I can mirror..

 

I put mine into the frame rail. I will try to take a picture on lunch.

What i suggest to you, if i'm right you only have one exhaust pipe that goes from the front to the rear on the drive side.
So it leave the passenger side free of exhauts pipe, so i would recommend to put it there, inside the lower section of the frame juse before where the frame is getting up. So it will leave the pump under the lowest point of the fuel thank.

 

Here how mine's is mounted. Maybe not as clean as you're....

 

All I can tell ya is I tried all that before going in tank.. On my 75 to get it lower than the tank woulda put it in harms way.. And I had vapor lock issues as well..

 

Thanks my pro and con right there.
Re arrange a whole lot of stuff for what should fix it, or get it out of the way all together and almost defiantly fix it...

 

The hardest part is dropping the tank. My least fav job on the heap. I have found it easier to set it up on large jack stands and remove both rear wheels. floor jack helps too. And I remove the filler hose and syphon as much fuel as I can out..

 

ill be sure to keep the peanut gallery up to speed..
making a short, or long list of tweaks in my build thread

 

do you need to support an in tank fuel pump? or can it just float around?

 

The factory gm ones are pinched in with a spring so they don't flop around