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914World.com _ 914World Garage _ pre 75 D-jet fuel pump

Posted by: echocanyons Apr 13 2005, 04:28 PM

I am trying to figure out the wiring for the fuel pump and the lines to and from the engine

The pump I have (from a 74 1.8) looks like it has a plug on the side of it and I cant seem to find the wiring to connect it to the car (72 1.7)

The fuel pump sits under the engine tray at the base opf the firewall right?

Are the lines routed through the engine tray are there two or three that go to the engine tray?

Where should the wiring for the fuel pump be?

Pictures are a big help too.

BTW I just picked up a 90000 mile gemini blue 72 with appearance pkg. from the second owner (who oned it for less than 6months)
The first owner was an older lady who bought it new and garaged it ten years ago, but managed to start it every week.
And best of all its an essentially rust free california car

This makes this the fourth 914 Ive owned...I think I'm hooked

Posted by: vsg914 Apr 13 2005, 04:39 PM

If your converting the car back to FI from carbs, The plug was probably cut off. Should be two wires under the battery somewhere. maybe above or below the engine shelf. One wire is brown(ground) the other should be black/red (power). You don't have to use the plastic plug if you don't have it. I would take this opportunity to relocate it to the front. do a search on the hose routing. There was a thread about this just two weeks ago.

Posted by: echocanyons Apr 13 2005, 04:54 PM

This car is still FI but the previous owner yanked the fuel pump to change it but never got any further than that.

I do think the fuel pump should be relocated to the front.

However, for purposes of diagnosis and operation I am going to leave it in its stock position (after I get it sorted I will change the location).

OK I found the wires and they are stripped. Is there a source for the connection plug?

Posted by: vsg914 Apr 13 2005, 05:00 PM

Might find a used one, but you don't really have to have it. Female wire connectors will work just fine. I use the ones that are insulated all the way.

Posted by: echocanyons Apr 13 2005, 05:14 PM

Thanks Curt I get it now I was wondering how I would do it without a connector but that makes sense.
So any ideas which side on the fuel pump is positive?

Posted by: vsg914 Apr 13 2005, 05:16 PM

It should be marked on the pump. I'll go check one and get back to ya.

Posted by: vsg914 Apr 13 2005, 05:18 PM

Yep. marked on the plastic surround for the connection.

Posted by: echocanyons Apr 13 2005, 05:23 PM

Guess I'll have to clean it

Thanks again

Posted by: echocanyons Apr 13 2005, 08:25 PM

OK fuel pump is mounted and wired.

I am having trouble fuguring out how the lines go.

The pump has three lines out

S= is from the tank after the fuel filter...right?

R= does the fuel pump output go from the fuel pump directly to the pressure regulator or just directly to fuel distributor?

D= does this tee from the return and the pressure regulator?

it is so simple with carbs I thought I could figure this out too.

Posted by: vsg914 Apr 13 2005, 08:46 PM

Tank to filter
filter to S on pump
D on pump to passenger rear fuel rail
passenger front to cold start valve to drivers front fuel rail
drivers rear fuel rail to pressure regulator
Pressure regulator to R on pump and "t"
T back to tank

Posted by: Dave_Darling Apr 13 2005, 08:51 PM

S = suction
D = druck (pressure)
R = return

Fuel comes from the tank, goes through the filter, goes to the S port on the pump.
High-pressure fuel comes out the D port on the pump, goes to the high-pressure loop on top of the engine.
The fuel pressure regulator is the end of that loop, "overflow" from it goes to a 'Y' connection that goes to the R port on the pump and to the return line running through the center tunnel and back into the tank.

--DD

Posted by: echocanyons Apr 13 2005, 08:57 PM

Great info Curt and Dave thanks a ton

Now lets see if it'll start

Posted by: echocanyons Apr 14 2005, 10:00 PM

Well no fire last night so I'm back at it tonight

I have a couple of questions

When the key is in the on position does the pump prime and shut off (a second or two) or fully pressurize?

When the starter is turned does the fuel pump do anthing else?

Where should I tap to test pressure the haynes is vague, do I need a special type of tester?

Can I and should I bypass the cold start valve?

Its gettin there

Posted by: vsg914 Apr 15 2005, 06:51 AM

[QUOTE]When the key is in the on position does the pump prime and shut off (a second or two) or fully pressurize?[QUOTE]

Should fully pressurize.

[QUOTE]When the starter is turned does the fuel pump do anthing else?[/QUOTE]

I think the fuel pump runs when the starter is turning.

[/QUOTE]Where should I tap to test pressure the haynes is vague, do I need a special type of tester?[QUOTE]

On the drivers fuel rail between the two injector hoses. You just need a simple fuel pressure gauge from flaps

[QUOTE]Can I and should I bypass the cold start valve?[/QUOTE]

It only works when the temp is below 35F or so. Disonnect it if you wish.

.