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914World.com _ 914World Garage _ fuel pump

Posted by: bd1308 Dec 17 2005, 12:06 AM

what fuel pump works with FI....that's not ten thousand dollars...?

I was thinking a bus fuel pump (input-and-output style) with some kind of pressure regulator using the return to the tank as the relief from the regulator.

the pump is mounted in the front....by the steering rack.

b

Posted by: Mueller Dec 17 2005, 12:36 AM

just about any 12vdc pump designed for FI except for perhaps CIS should work.......

QUOTE
I was thinking a bus fuel pump (input-and-output style) with some kind of pressure regulator using the return to the tank as the relief from the regulator.

you cannot have an output without and input

you pretty much described the factory FI system.....

the stock 914 regulator is adjustable (at least mine is, not sure if all are or not)

Posted by: bd1308 Dec 17 2005, 12:44 AM

QUOTE (Mueller @ Dec 17 2005, 12:36 AM)
just about any 12vdc pump designed for FI except for perhaps CIS should work.......

QUOTE
I was thinking a bus fuel pump (input-and-output style) with some kind of pressure regulator using the return to the tank as the relief from the regulator.

you cannot have an output without and input

you pretty much described the factory FI system.....

the stock 914 regulator is adjustable (at least mine is, not sure if all are or not)

Mike I was talking about a pump without the crazy 3rd port.....I did have one in my car (needed a rebuild or replace) but the mechanic took it, or its missing or its in my box O parts.

b

Posted by: Mueller Dec 17 2005, 12:50 AM

'75/'76 pumps only have an in/out........so just hook it up like a '75/'76 FI equipped car.....

I'm sure pelican or someone else has got to have a diagram for you....

most pumps only have the 2 ports...........

Posted by: bd1308 Dec 17 2005, 12:54 AM

i had forgotten about the late pumps....

okay, well thanks mike. so as long as the pump provides around 40PSI of pressure everything should be good?

wait, mike....are the late-style 914 regulators the same as the early-style? I have a 74...

b

Posted by: michelko Dec 17 2005, 02:30 AM

Hi,
you can use nearly every fuel pump used in L-Jetronik or modern Motronik cars.

They should bring max 3 bar pressure, 12 Volt is standard.

At the moment i am using a VW-Polo pump. Last one was from a OPEL Vectra (see picture) nearly the same look then the original late style 914 pump just another parrt number. But worked fine for a few km.

Attached image(s)

Posted by: michelko Dec 17 2005, 02:47 AM

and this one i am running now for 2000km (VW-Polo part) without problems.

Attached image(s)

Posted by: bd1308 Dec 17 2005, 03:22 AM

thanks.

I would have said some german, but i'm afraid of making a mistake...

anyway, good night. I'll check tomorrow and see what I can find.

b

Posted by: Dave_Darling Dec 17 2005, 08:25 PM

Any 12V pump that can provide the appropriate amount of pressure (~3 Bar; ~45 PSI) and flow rate (I forget now, is it 50 liters/minute?) should work fine. Just make sure you can hook up the inlet and outlet fittings correctly to the fuel system, and mount it decently.

--DD

Posted by: airsix Dec 17 2005, 09:30 PM

QUOTE (Dave_Darling @ Dec 17 2005, 06:25 PM)
Any 12V pump that can provide the appropriate amount of pressure (~3 Bar; ~45 PSI) and flow rate (I forget now, is it 50 liters/minute?) should work fine. Just make sure you can hook up the inlet and outlet fittings correctly to the fuel system, and mount it decently.

--DD

What Dave just said. I'm running a pump off a BMW 325. My engine dosn't know the difference. Any pump that will provide adequate flow/pressure will work. The regulator takes care of the rest.
-Ben M.

Posted by: bd1308 Dec 17 2005, 09:32 PM

okay thanks people....

i was over at the FLAPS today....I was getting ready to ask them car related, but I knew they wouldnt have the answer if the computer didnt give it to them.

BMW 325
VW Polo (?)
OPEL Vectra (??)

b

Posted by: billd Dec 17 2005, 09:35 PM

When I found the 3-port pump in my 73 dead, I replaced it with the 2-port pump for a 75-76 and just eliminated the "Y" connector on the return. Summit Racing also has a Mallory pump for FI that should work.

Posted by: KELTY360 Mar 22 2006, 08:02 PM

QUOTE (billd @ Dec 17 2005, 07:35 PM)
When I found the 3-port pump in my 73 dead, I replaced it with the 2-port pump for a 75-76 and just eliminated the "Y" connector on the return. Summit Racing also has a Mallory pump for FI that should work.

I'm not sure I get this. Do you just block off the return system when changing to a two-port pump? What is the purpose of the return system? I have to replace my 3-port pump on my '74 2.0 FI and I'm looking for the CSOB solution.

Marc

Posted by: swl Mar 22 2006, 08:18 PM

In another thread a mallory 4060fi was recommended. I have a used one but haven't had a chance to test it yet - need the right fittings for it. It does have a return port on it that is supposed to assist in priming. Seems to run around $150 new.

Posted by: jimkelly Mar 22 2006, 08:22 PM

I choose mine per jake raby suggestion.

http://www.914world.com/bbs2/index.php?act=ST&f=2&t=36629&hl=4060fi

jim

Posted by: Dave_Darling Mar 22 2006, 09:14 PM

QUOTE (KELTY360 @ Mar 22 2006, 06:02 PM)
I'm not sure I get this. Do you just block off the return system when changing to a two-port pump?

Nope, the return system must be there and be functional for the fuel system to have the correct pressure. So you can't completely eliminate it.

However, you can get rid of the branch of that circuit that goes to the fuel pump. The third port (the "R" port) on the early fuel pump is Y'd into the return line. If you don't have an "R" port on your pump, you can eliminate that Y. Just run the one line from the outlet side of the fuel pressure regulator to the return line in the center tunnel.

--DD

Posted by: KELTY360 Mar 22 2006, 11:17 PM

Thanks, I think I've got it now. I would like to know the reason for the return system if anybody can explain.

Marc

Posted by: pnewman Mar 25 2006, 02:31 PM

I could be wrong about this but I am sure that other members will correct me.

The Fuel comes from the tank to the New fuel pump then out the Pressure side of the fuel pump and then through your tunnel and to the pressurized side of the fuel rail system.

After the fuel rail is the fuel pressurized then the rail continues to the regulator. Whatever excess fuel pressure that is above the required amount per the regulator is then discharged into the return fuel line back through the tunnel and into the fuel tank.

Think of the return fuel line as a pressure dump for excess psi so as to not over load the fuel circuit.

I am in the process of relocating my oem fuel pump to the front and simultaneously switching over to a 2 port cylinder style fuel pump from the dreaded 3 port pump.

I will be using you as my gineou pig I guess.

Let me know if it works..
If I don't hear from you I will assume that you died in a firey 914 fuel pump mishap and then I will have to hit the books again.

Pete

Posted by: Jeff Nelson Mar 25 2006, 07:39 PM

Here's a pretty good diagram of an L-jet setup:
http://www.pelicanparts.com/914/technical_specs/914_18FI_diag.htm
This should be the same basic configuration as used in the 75-76 2L D-jet models. On my 73 2L the charcoal canister is up front and the tubing that connects it to the engine runs through the driver's side long.

One more thing, if anyone is looking for a new Bosch FP these guys have a good price on one:
http://www.autohausaz.com/search/productx.aspx?sid=2q5zjo2qr4034jn2lbxofl55&makeid=800019@Porsche&modelid=1263204@914%20&year=1975&cid=22@Fuel%20%26%20Air%20System&gid=6256@Fuel%20Pump,%20Electric
I just ordered one from these guys. I could go to the junk yard but it's too muddy right now. (Occasionally I like to use a new part.)

Posted by: pnewman Mar 25 2006, 08:58 PM

That is a good price for a new bosch pump without haggling etc.