Vacuum diagram for M635?

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ericono
Posts: 500
Joined: Fri Mar 23, 2007 1:51 am
Location: Spartanburg, SC

Vacuum diagram for M635?

Post by ericono »

Just checking, does someone have a diagram showing the vacuum line routing for the M635? I'd like to go through and make sure I am updating all the old hoses which most likely are cracking by now.

Thanks,

Eric
'85 M635, '00 528iT, '98 Z3
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TN_M6
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Location: Middle TN USA

Post by TN_M6 »

The vacuum lines are pretty much self explainatory I think.
Crankcase to plenum, big one.
Manifold to FPR and interior temp sensor, small ones.
Drain line from the plenum(hidden underneath) to dipstick, small like fuel line that you don't want to miss.
Another like it for the vapor recovery system.
Then the idle air stabilizer valve lines which run and tuck down under the intake runners.
Of course the six bigger boots to the plenum and the boot to the AFM.
I think it's about this simple.

But if you are chasing vacuum leaks and poor running you might look at o-rings too:
intake plenums
idividual TB air adjustments
large coarse idle adjustment
the injectors

I would hope the throttle seals are OK but you should lube all the linkages while you at it.

Do you plan to re sync all the throttle bodies after replacing things? I think you will need to and I think that is harder than figuring out the routing. IMO if you mess with any of this you'll need to balance the ITB vacuum each and every time and maybe also adjust the TB butterflies to be sure it's all in sync. It's a pain but makes it run smooth.
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ericono
Posts: 500
Joined: Fri Mar 23, 2007 1:51 am
Location: Spartanburg, SC

Post by ericono »

Hey, thanks for the list. I'm not actually having any rough idle issues, just trying to do some preventative maintenance while in the engine bay. I'll have to look into the ITB adjustment.

Thanks again,

Eric
'85 M635, '00 528iT, '98 Z3
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