Colin

Fuel Lines + Fuel Pressure Regulator for 318i manifold?

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Maybe this is a dumb question, but on my megasquirted m10 I've got the 318i manifold with 02again's IAC valve adapter. My question is:

How the heck does the plumbing go for the fuel rail and the fuel pressure regulator?

Thanks in advance.

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It is my observation that there is a feed line to the fuel rail and a return off the rail. The pressure regulator is bolted directly to the fuel rail and is controlled by vacuum.

Someone else might have more info.

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It is my observation that there is a feed line to the fuel rail and a return off the rail. The pressure regulator is bolted directly to the fuel rail and is controlled by vacuum.

Someone else might have more info.

That is what I thought but what confuses me is that the fuel pressure regulator not only has the vacuum line on it but seems to have some sort of fuel-line sized connection (output) on the other end.

On the fuel rail, I assume that the end most connection is the fuel return line and the inner one is the input?

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You plumb from the fuel filter directly into the fuel rail (at the back of the rail). The regulator attaches to the rail and the output is plumbed to the return line to the fuel tank. The vaccuum line connect to the intake manifold.

I hope I understood your question correctly.

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I believe you are correct about the orientation of the fuel inlet and return. That large port on the FPR is what goes onto the fuel rail. It looks similar to a fuel injector end that also goes to the fuel rail (in four locations).

In the photo here http://www.bmw2002faq.com/content/view/16/32/ you can barely see the FPR at the end of the fuel rail (closest to the radiatior) with a red vacuum hose hooked to it.

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If I recall correctly there are actually two different fuel rails that one can find on early EFI M10 motors, one has more outlets than others. Take a look at the attached link and then scroll down to where you'll see two different fuel rails. The upper illustration is the one that you want. http://www.realoem.com/bmw/partgrp.do?model=1374&mospid=47315&hg=13&fg=15

Ah, well that answers my question. The fuel rain I have has two inlets plus the FPR. Its that second inlet that was confusing me so much.

Am I right in assuming that I can safely plug the second inlet?

Thanks all.

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Am I right in assuming that I can safely plug the second inlet?

I plugged mine with epoxy. So far so good. I suppose you could weld it shut also.

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Am I right in assuming that I can safely plug the second inlet?

I plugged mine with epoxy. So far so good. I suppose you could weld it shut also.

Sounds good. Thanks.

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Am I right in assuming that I can safely plug the second inlet?

I plugged mine with epoxy. So far so good. I suppose you could weld it shut also.

Imagine what could happen if the epoxy plug fails, with 45 PSI of fuel pressure. Good luck.

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I like the idea of the T connection. I have that same fuel rail and was looking at everything this morning on my kitchen table and was a bit stumped by the 2 fuel line connections to the fuel rail. The real OEM site provided how it was supposed to work (cold start injector where my IAC valve is going to go.), but I was a bit stumped on how to safely block that line off without turning my car into a car-b-que. I think I will go with the T approach instead of finding another fuel rail or trying to block off one of the ports.

Thanks!

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I like the idea of the T connection. I have that same fuel rail and was looking at everything this morning on my kitchen table and was a bit stumped by the 2 fuel line connections to the fuel rail. The real OEM site provided how it was supposed to work (cold start injector where my IAC valve is going to go.), but I was a bit stumped on how to safely block that line off without turning my car into a car-b-que. I think I will go with the T approach instead of finding another fuel rail or trying to block off one of the ports.

Thanks!

Your rail is an early one and you are correct that the extra nipple provided fuel to the cold start valve. Later rails did not have the extra nipple and had a tee in the fuel line to the cold start valve (a cost cutter design).

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