Print Page - Fuel pump questions???

I pulled tank from the parts car, it had a v6 in it. The tank was good and the fuel pump in the tanks looks new too. It also had one on the frame rail. Now the questions, can I use the in tank fuel pump with v8 carb engine? I want to delete the frame pump. What kind psi will the in tank pump?

Ditch both pumps and buy a new 190 or 225 lph pump. Why guess when you can just spend $120 or so dollars and do it right.

Darren

He wants to switch to a carb setup.

Clean up on isle 9...missed the carb part but my earlier statement still stands in conjunction with this thread:

http://mustangforums.com/forum/5-0l-1979-1995-mustang/10393-efi-carb-conversion-using-stock-electric-pump.html

Lots of guys have converted to carb utilizing the stock fuel pump on the Fox Mustangs. Some guys have gone as far as getting the stock pickup for the 83-85 Mustangs as they were carbureted but it all depends on how you want to go about it.

Darren

I got ya, I am going back carb, the car has no computer or engine wire harness, so I was going to use a carb. I was hoping the stock in tank pump would be enough for carb.

The in tank pump can be used with a bypass set at 6-8 LBS!!!

Bypass? Is that a regulator?

Quote from: TOM Renzo;398897

The in tank pump can be used with a bypass set at 6-8 LBS!!!

Not if the car was a CFI set-up with the high pressure pump on the frame rail......the in tank pump is only a lift pump and peaks at about 2-3 PSI.
When I went from CFI to carb on my 84, I used both pumps with a Mallory 4309 regulator and it works well.
EDIT: The 4309 is a return style reg.

NO just restrict the return line to 6-8 lbs. Another words you can build a system using the in tank low pressure pump if it exceeds 8 LBS. If memory serves me the in tank pump puts out 10 LBS +or - If it is closer to 8 lbs you can run it without a bypass. Check it with a gauge!!!

Quote from: TOM Renzo;398907

NO just restrict the return line to 6-8 lbs. Another words you can build a system using the in tank low pressure pump if it exceeds 8 LBS. If memory serves me the in tank pump puts out 10 LBS +or - If it is closer to 8 lbs you can run it without a bypass. Check it with a gauge!!!

I did. If the car only had an in tank pump like the Mustang or Lincon etc, yes you can.

Here is an in depth write up I did a while back...........just couldn't remember where I posted it....LOL.

http://sbftech.com/index.php/topic,15112.msg146399.html#msg146399

I have converted many a caddy from EFI to carb in the old days and it is very simple. Use the in tank pump only i think it is a low pressure unit. Been a while since i checked one. If it exceeds normal carb pressure of 6-8 LBS you can design a restrictor to send the excessive pressure back to the tank with the stock return line. No need for a regulator. I have dun this several times on the old EFI Caddys with perfect results. Using both pumps is silly as why would you want to reduce all that pressure when the in tank pump is a low pressure unit. Just me could be wrong!!!

Besides the restrictor and dumping into the return, a large variable resistor or could be used to lower voltage to the pump... Varying voltage to pump to regulate pressure is how the returnless systems on newer vehicles operates(though not with a resistor, those use PWM)...

Supposedly the pumps for constant voltage aren't rated for varying voltage, but there have been instances of the older pumps used without issue... Running the pump at say 9v with the restrictor set for a carb would allow fine tuning pressure with the rheostat... With a fuel pressure gauge and rheostat mounted in the dash, pressure could be dialed from the driver seat...

IF I ever get the 331 in the Bird it will be carbed and use a similar system...

If I use a fuel filter with a return on it, like from a 4.0 ranger, I can put a regulator by the carb and just use the in tank fuel pump?

Tried the fuel pump today, I get fuel to the carb, I have a pressure gauge no regulator. I turned the key on and walk to the front of the motor and waited until the needle moved, it got to about 1.5lbs and then I noticed fuel coming out the vent tube on the carb, next to the inlet port on carb for gas. Not sure if the psi from the factory intank pump (no frame rail pump) is to much or the floats on the carb are sticking? I was thinking on getting a non return style regulator and then try? any ideas?

since you have no rail mounted fuel pump, your in tank pump is pushing far too much pressure, so if you are using a carb, it does need to be replaced with a low pressure pump. a pressure regulator isnt going to help the issue at all.

Quickshift nailed it. You need a regulator with a return at the regulator to use the in-tank pump. You must get the pressure down before it gets to the carb. Sorry I am not familiar with the filter you mentioned. My setup returns straight to the tank from the regulator.

Quote from: 83TB;424875

Tried the fuel pump today, I get fuel to the carb, I have a pressure gauge no regulator. I turned the key on and walk to the front of the motor and waited until the needle moved, it got to about 1.5lbs and then I noticed fuel coming out the vent tube on the carb, next to the inlet port on carb for gas. Not sure if the psi from the factory intank pump (no frame rail pump) is to much or the floats on the carb are sticking? I was thinking on getting a non return style regulator and then try? any ideas?

Please re-read my link in post #11 and post your findings back here.

Got my popcorn out of the microwave, my cold beer, and now just waiting to see if the intake pump survives or if it gets the ax and a Holley pump finds its way in the car.

Darren

http://www.summitracing.com/parts/frm-g3499/overview/
that is the filter I was referring to in earlier post, my thought of asking that was so I did not have to run another line up the regulator in engine bay. My thought is if you had a dead head regulator up stream from it, if it would allow the extra fuel to return to tank, that way I could mount it close to the tank for a short return, just not sure if that is the way that filter was made to do.

Quote from: flylear45;424879

Quickshift nailed it. You need a regulator with a return at the regulator to use the in-tank pump. You must get the pressure down before it gets to the carb. Sorry I am not familiar with the filter you mentioned. My setup returns straight to the tank from the regulator.

a regulator isnt going to cut it with the fuel injection pump, the pressures are just too high. i tried that years ago with my old 83 grand marquis that had CFI. and i used a good holley pressure regulator with a return line, and the pump still blew fuel past the regulator and flooded the carb. i had to swap to a low pressure pump in the tank.

Quote from: QUICKSHIFT;424885

Please re-read my link in post #11 and post your findings back here.

12.3 volts, fuel line off carb, line plugged off, 2psi max, factory fuel pump in tank only, so if I put another pump on frame, so I can the volume and pressure that I need.

Quote from: rbohm;424911

a regulator isnt going to cut it with the fuel injection pump, the pressures are just too high. i tried that years ago with my old 83 grand marquis that had CFI. and i used a good holley pressure regulator with a return line, and the pump still blew fuel past the regulator and flooded the carb. i had to swap to a low pressure pump in the tank.

I beg to differ. I'm using the stock in tank lift pump (approx 2psi) along with the high pressure frame mounted CFI pump and a Mallory 4309 regulator to feed my 700DP.....ZERO problems.

Quote from: 83TB;424915

12.3 volts, fuel line off carb, line plugged off, 2psi max, factory fuel pump in tank only, so if I put another pump on frame, so I can the volume and pressure that I need.

If you reinstall the frame mounted pump and leave the in tank pump as is, you can run the same setup as I am with good results. This will produce approx 33GPH@ 7PSI. The Mallory reg is the secret as it is built different to prevent "creeping" and provide a stable pressure and flow. This will support 325HP.

I got a freebie from a friend today,http://aeromotiveinc.com/products-page/fuel-pumps/11209-h0-fuel-pump-38-npt/

Going to use this with the intank pump, not sure if going to try like the instructions say, or get a regulator and return line, the ad says does not need one, but we will see.

Quote from: QUICKSHIFT;424925

If you reinstall the frame mounted pump and leave the in tank pump as is, you can run the same setup as I am with good results. This will produce approx 33GPH@ 7PSI. The Mallory reg is the secret as it is built different to prevent "creeping" and provide a stable pressure and flow. This will support 325HP.

Quote from: 83TB;424932

I got a freebie from a friend today,http://aeromotiveinc.com/products-page/fuel-pumps/11209-h0-fuel-pump-38-npt/

Going to use this with the intank pump, not sure if going to try like the instructions say, or get a regulator and return line, the ad says does not need one, but we will see.

Make sure you use a return line. The in tank pump is designed for constant flow NOT dead headed. If you are determined to use that aeromotive pump in a dead headed system without a return line you MUST remove the in take pump.

Quote from: 83TB;424906

http://www.summitracing.com/parts/frm-g3499/overview/
that is the filter I was referring to in earlier post, my thought of asking that was so I did not have to run another line up the regulator in engine bay. My thought is if you had a dead head regulator up stream from it, if it would allow the extra fuel to return to tank, that way I could mount it close to the tank for a short return, just not sure if that is the way that filter was made to do.

Hmmm. Maybe.

For $2.95 and the fact that you have what you have, it may be worth a shot. It's not my first choice though.

going to use the aeromotive pump and a return regulator, I was thinking about the factor set up to (quick shift), but afraid the the ler would hit, cause it has the filter and pump and bracket together, so I took it apart and mounted just the aeromotive pump to the bracket, going to see if I can make this fit some where like this.

Quote from: 83TB;424980

I was thinking about the factor set up to (quick shift), but afraid the the ler would hit, cause it has the filter and pump and bracket together,

.......ya, forgot about that.....I relocated mine to the front of the shield protecting the tank behind the axle when I went with duals.

Quick shift you have any pics of that set up?

One other thing you need to factor in is the size of the feed and return lines. I have twin Mallory Comp 140's that are Y'd into a single AN-8 (1/2") feed line to the front of he car. From there the flow is split with another Y and one leg goes to a Mallory return style regulator to the carb and the other leg goes to the fogger system via a Holley regulator with no return per NX's instructions.

I originally had an AN-6 return line but I could not get the fuel pressure at the carb below 14 psig or something like that. Called Mallory and found out that I was way undersized on the return line. I needed an AN-10 (3/4") due to the volume of the two pumps going into the single AN-8 feed line. Once the AN-10 return line was installed the problem was solved.

Long story short had I just used a simple calculator I could have done it right the first time and saved myself a lot of headache.

Darren

Quote from: 83TB;424995

Quick shift you have any pics of that set up?

If there wasn't any snow/salt on the roads, I'd slip out to the shop, pull it over the pit and snap a few. The car is stored here @ home, but leave it with me and I'll see if I can jack it up and take pics....not much room....sorry.

Found one of the reg mounting.....not very good but you get the idea.

Just little update, the factory fuel will get about 2.5 psi, while the motor is crank, I have been cracking the motor and letting idol while checking out timing and other stuff, leaks, etc.... after xmas and new years, planning on doing the frame mount pump and regulator with return. I did find a good spot for the pump, after I install it I will post some pics of it and the fuel filter install.

Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: 83TB on September 22, 2012, 02:43:15 PM