I have a carbed 350. The person I bought it from has an electric fuel pump inline with the original one in the tank. The one in the tank is no longer working. My questions are these....1) Can fuel be pulled through the original pump in the tank or does it need to be removed? 2) Isn't it true that the return line to the tank does not extend into the tank as far as the main feed line?

The previous owner hacked a lot of this cars wiring and harnesses. I was also told that he ran the new external electric pump using the return line to feed the carb versus the feed line.

Trying to figure out how to get fuel to the carb properly without too many PSI. The car was originally a 2.8 V6. Now it houses a 350 with Edelbrock 650 carb.

Thanks in advance.

 

Yikes. OK - the external fuel pump will draw through a dead internal pump, but not for long - it'll burn itself up trying. And you don't know if it is drawing through, since you're not sure if he used the feed line or the return line to draw through.

If it were me, at this point I'd trace the return line and feed line all the way to the tank, and find out exactly what is connected where. If the PO tapped into the return line for the external pump, and the car doesn't seem to die with low amount of fuel in the tank, then it may just be a matter of regulating pressure. But if the external pump is drawing through the dead internal pump, you'll need to correct this.

In the end, I'd think you'd want one of three scenerios...

1) replace the intank pump with a TBI pump, plumb it correctly through the feed line to the motor, use a return-style regulator like the Mallory 4309 to bring the pressure down for the carb (3-7psi), and ditch the external pump.

2) use the external pump, either on the feed line and remove the internal pump, or on the return line if you find out the return line runs deep enough into the tank, regulate the pressure correctly

3) remove the intank pump, and the external pump - install a carb pickup in the tank, and run a mechanical pump off the block - this assumes you have a place on the block of this motor for a mechanical pump, and you have the right lobes to run a mechanical pump

**** Given this hacking by the PO - if you have a 700R4 transmission, I'd make sure the TV cable is adjusted correctly, the throttle brackets are good and strong and don't flex under the pressure of the TV cable, and that the proper geometry corrector was installed on that carb for the TV cable - alot of folks don't realize that these 700R4's are very testy when it comes to their TV cables - it's not just a kickdown as in the old days, and the pressures are really important, thus the geometry and 'pull pressures' are critical for the tranny

 

I checked the lines and its running off the main feed line not the return line. I am not sure what psi is being given to the carb, so I am going to try and get a fuel pressure gauge with a short piece of 3/8 tubing and put it on the carb for test purposes. I think my problem may be the fact that the fuel pump is in the engine bay. They are designed to push fuel not pull. I may try reinstalling the pump near the tank and see if my pressure improves. If that is not satisfactory, I am going to purchase a new pump that came with the 2.8 V6 in the tank and then connect the Mallory 4309 in the engine bay and adjust accordingly to the carbs needs and then tweak as needed.

I am awaiting the cost on my motor before I do anything. Once I know that, I am going to finish all the other minor prep work I want to do before I put the new motor in. I need to cut the motor mounts and install new ones since someone welded them in place. Install a different tailshaft on the 700R4 so I can mount up the torque arm bar, install the panhard bar, drain the tranny and put new screen and gasket and refill...change out some suspension bushings and end links, install new speedometer cable and get the gauges working, route some new wiring for the A/C, install a power steering pump, sounds system wiring, and new lights in the dash. This car was all chopped up wiring and mechanically wise, but the body is in mint condition with no rust anywhere...except the battery tray. Installing 4th gen bottles and tray in place. Also, I have redone the red interior to black but didnt install it yet and waiting for my new carpet to arrive.

Not much stuff to do, but definitely needed and wise to be proactive. It will be nice once I am done. Lastly, new red paint on the car once the badges are shaved and filled in. Getting antsy waiting to do everything. I would do it all at one time if I had everything here at once.

 

Pics?

 

Its all apart right now. Maybe wednesday I can post some of the before and after of the interior. And then one of when I got the car and what I have done so far.

 

First i am new at this and it has taken me 2 months to find a thread like this.

im looking at scenerio 1 with the tbi pump. What kind of tbi pump do i need does it go in the tank? how do i install the mallory 4309 regulator this is were ive hit a snag completely lost with fuel delivery and how to in this area. can i use the factory fuel lines? i have them out do to undercoating. the car is completley stripped down no motor trans nothing interior gone everything is out of engine bay i am now ready to reinstall fuel lines but curious to witch route to take im installing a 350 5.7 crate motor with 350 turbo trans what would be the best fuel delivery scenerio for this application.

Any help will be GREATLY apreciated.

Thanks
thomas