Hey everyone, i was wondering what will be required for me to switch to a low pressure fuel pump for carbs. Do i plug off the return line or do i still use it somehow? Anyone have any specific examples of what they did with all of the extra lines after removing their fuel injection system? Thanks

First: Why are you switching to carbs?
Second: You can buy a low pressure fuel pump for carbs for roughtly $50.
Third: A fuel pressure regulator can help with the pressure.
Fourth: You will have to "close" the return fitting at the fuel tank. Maybe even something as simple as a bolt in the end of the fuel line with a fuel injection hose clamp. There is only a feed and return line with FI so there are not alot of extra lines unless you're counting the cold start line

This will get you started:
http://www.914world.com/bbs2/index.php?showtopic=25954

I recommend using a rotary pump. They're MUCH quieter!
I used the CB Performance pump and liked it.

As for the return line, you can safely cap it off in the engine compartment. That way, if you ever go back to a setup where it's needed, you don't have to run new lines.
However, it is beneficial to run the return, even with carbs. It will require some extra work to set this up, so most people don't do it.

Make sure you run the thick FI spacers between the heads and the intake runners to prevent heat soak.

As for the wiring, the FI brain and and harness are pretty much one unit. Simply remove those. The rest of the wiring is still needed. Coil, Tach etc.


And lastly, if it's a stock engine, i'd rather fix the FI than run carbs ...
Andy

Not trying to hi jack and maybe this question will help the original poster.

Andy, I would like to use the return line on my carb set up just because of the benefit of colder gas circulating instead of hot has sitting. I have a low pressure (3.0 psi) pump. It seems like the best place to insert the return line would be After the second carb. I don't have that type of fitting on the second carb and was considering a tee right before it. I'm worried about losing pressure. If the tee has a smaller outlet to the return than the outlet to the carb, do you think it will work? Suggestions?
Thanks.

I agree with Andy. I think you are creating unnecessary expenses as compared to the fuel injection. I believe you can get equal and better performance from FI. I did a conversion on Alfa's and got better performance with hot cam and mechanical injection (stock config) several times. Besides you do not have to worry about altitude changes as we do in Flagstaff to California . I have helped several friends over the years making conversion to carbs and most wanted to go back (Porsche and Volkswagen)

Just my thoughts.

Steve Hurt

I bought an engine that is all set up with carbs on it. I just want to see if the engine even works. If it works and i dont like the carbs, ill put all my FI stuff back on. I have a LP fuel pump so i dont have any expenses there. Also, when i bought my car, my high pressure fuel pump for the fuel injection was running off of the coil. I think my relay board has some issues.

Before you get too distant from the seller, find out what cam is in the engine. The cam may prevent you from going back to FI. Back to your original carb question, I would think there is a pressure regulator, like in the FI system, for the carb system.

Carbs are OK just different.
No need for return line and no real way to route it from the pressure regulator (Holley from Summit)
I used the CB pump for 6 years and it finally gave up the ghost last week. Now have a pimp ass pump from Summit and a gauge to set the pressure.

...Lots of ideas in this post Brandomc. here are a few more...1. You will need a low pressure fuel pump, one that is NOT for a fuel injection system. 2. you will need a LOW PRESSURE fuel pressure regulator, and a way to test fuel pressure. fuel pressure should be set at 3.5 psi. 3. you will need a good (metal cannister) fuel filter. 4. you should ensure the fuel pump is "soft" mounted w/ rubber soft mounts. you will need a ground wire to the pump body. the "hot" wire should have a fuse. 5. there are many places you can mount the fuel pump, but THE ENGINE BAY should not be one of them. 6. I cannot suggest strongly enough to run NEW FUEL LINES for the entire system. (the fuel lines are about 35 years old) 7. NOW is a good time to pull the gas tank, and clean it out, especially the fuel strainer/screen filter. You will need to plug off the small line,(inlet fitting) which is/was the fuel injection return line. 8. you will probably find that 5/16 '' fuel line,...( or 8 mm) fits the carburator fittings best. 9, use s.s.hose clamps. 10. install a new metal fuel line through the chassis. finally, If you will do all of this at one time you can eliminate a "fire hassard" as a cause for concern for quite some time. routine maintenance checks are necessary for any fuel system. murray

Is there any reason you can't use the stock fuel filter?

3. The idea is to get and use NEW parts. I think the o.e.m. fuel filter is somewhat more expensive than a 5/16th inlet / outlet metal fuel filter, available for about $6.00 at your local auto parts palace.

You can buy an adjustable regulator with a return port. Hook the return port to the return line and run the FI fuel pump. Use a pressure gauge to dial in the pressure. This will allow cool fuel to circulate through the system and you can use the same fuel pump.

Using the stock FI pump and a regulator to get the pressure down to 3.5 psi is a bad idea IMHO. Most regulators cannot handle the approx 90% pressure drop you are looking for. Use a low pressure pump - the CB has a built in regulator to 3.5psi, so you can ( but not reccomended) get away with not adding the extra regulator.

Cevan,
I have a metal filter that is capable of being opened and cleaned (its a stone filter)
I like it better. Go to summit racing for that.
I got the CB performance rotary pump.
I am heading the same way....if I ever get out there and finish building that motor...its close.

Rich

Summit racing filter, CB pump, and Holley pressure regulator gives you the perfect control over the fuel pressure.