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Hello all,

I have been looking into replacing some parts in the fuel system of my 635.
Although my dad's 3.0Si has L-jet, it does not have the same fuel rail system.
It is the M90 engine with L-jet, which happens to be the same as the M535i.
According to Real OEM, it has the same fuel rail (as we expect).


http://realoem.com/bmw/showparts.do?mod ... g=13&fg=15

My question is for item 8 (sleve), how it is removed? Is is just friction fit? I will have to replace the fuel lines (items 2 and 7) that have started cracking.



Also, it looks like the lines from the rail to the injectors are deteriorated. Are these a standard BMW rubber fuel hose or are they part of the rail itself? The image above does not indicate any additional hoses...

What is the best way to get int here to replace these--- remove the intake and runners?

Thanks in advance!

If they're original, you're in for a fight. Part #8 is just a collar, it will slide off once the fuel line is off, which is the hard part. The original fuel line is very tough, you aren't going to pull it off, I spend some time with an exacto knife, the factory manual says to burn them off with a soldering iron, which I'm uncomfortable with given the proximity to gasoline. But be careful not to nick the metal or else you can have a leak. Really, any fuel line that is original should be replaced now, it's over 30 years old. BMW fuel line is very good quality and not that expensive, and downright cheap for FI rated line from Autohaus, once you find it, it's not listed for every application so some searching for 70s-80's BMWs is in order. You'll also need clamps, again, the original line didn't need it, but the replacement does.

No 8 is a crimped fitting, when you replace the line you can use the standard fuel line fitting (no 3). Same with the other short lines to the injectors, which can be replaced with standard fuel lines. It's much easier with the runners removed.

...tom




-----Original Message-----
From: tschultz <littleguyschultz@gmail.com>
To: tech_forum <tech_forum@firstfives.org>
Sent: Mon, May 13, 2013 8:40 pm
Subject: M90 Fuel Rail Questions

#AOLMsgPart_1_6bf4e06e-b762-4dab-a67d-7a3e4b92dddf td{color: black;} Hello all,

I have been looking into replacing some parts in the fuel system of my 635. It is the M90 engine with L-jet, same as the M535i.
According to Real OEM, it has the same fuel rail (as we expected).


http://realoem.com/bmw/showparts.do?model=5331&mospid=47199&btnr=13_0185&hg=13&fg=15

My question is for item 8 (sleve), how it is removed? Is is just friction fit? I will have to replace the fuel lines (item 2) that have started cracking.



Also, it looks like the lines from the rail to the injectors are deteriorated. Are these a standard BMW rubber fuell hose or something else? The image above does not indicate any additional hoses...

What is the best way to get int here to replace these--- remove the intake and runners?

Thanks in advance!




1980 635CSi
1985 535i









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All great information!
This is one of the itemns on my list to do, but it sounds like it may be something to do when I can leave it in the garage taken apart for a few days in case it's a bit stubborn.

IF #8 is crimped and not a collar, just cut it off and use a hose clamp. Standard BMW fuel line for the injectors too, but you need clamps, the stuff you get now while very good isn't the same as the original. The original is unbelievable tough and will not pull off, it will break first, you have to cut or melt it off.

I used standard fuel line cut to length with hose clamps when I replaced all of mine to the injectors. It's practically impossible to do it without removing the intake runners, and as long as you do that, you might as well remove the log manifold.

When you remove those chances are the gaskets between the manifold and runners will break off or tear, so be prepared with new gaskets ahead of time if you go that route.

There's a FAQ (written by Adam).

I've done three systems using it. I agree with Mike it takes a new Xacto blade, careful cutting under the retainer cups. Last set was three years ago, no leaks.

OEM BMW fuel line fit under the retainer cups (look like baby cereal bowls) fine. Check the outside diameter of any purchased new to fit snug. I admit I hate seeing, using dinky do hose clamps. Use an old piece of fuel line you've removed to cut the six pieces to exact length.

Think before you push the new lines on. Check the retainers are in place and the injector hold down rings are in proper order.

Same as the old line, new line must be cut to get it off the barbed fittings if you don't get things in proper order.

Good info, thanks guys! Haven't tackled yet, but once I get proper space that I can work on it and have it apart for a few days...
May be a good time to do some other needed maintenance link valve adjustment and new exhaust manifold gaskets.