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injection cleaning vacuum lines

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635sharknose
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injection cleaning vacuum lines

Post by 635sharknose » Tue Oct 29, 2019 7:47 pm

I want to perform an injection cleaning using injection cleaner fluid. My goal was to let the motor suck it up through the vacuum lines.
Drove the car to warm it up a bit and opened the can with fluid.
Pulled the vacuum line (see marked with 1) but to my surprise there was no vacuum at all.
Pulled another vacuum line (see marked with 2), same result.
Pulled the line that comes from the charcoal canister (marked with 3 and 4) also no result.
Motor is running fine, no stalling, so I expected no vacuum leaks.
What am I doing wrong here?
Thanks for the help!
vac lines.JPG
vac lines.JPG (144.99 KiB) Viewed 1819 times
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1987 635CSi Bronzitbeige

bakemono
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Re: injection cleaning vacuum lines

Post by bakemono » Thu Oct 31, 2019 2:12 pm

You would need to use a vacuum line that is connected directly to the intake manifold. Maybe the one for the FPR? I don't know if there is any other option on your car. The ones for evap are connected outside of the throttle body so they have practically no vacuum at idle and only a little bit even when the throttle is open.
'82 528e - M50B25 + GS6-37BZ
'83 633CSi - Megasquirt and a 3.46LSD

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635sharknose
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Re: injection cleaning vacuum lines

Post by 635sharknose » Thu Oct 31, 2019 6:19 pm

Thanks for your reply.
That would mean the hose which I marked with 2. This has no vacuum but I did try it after the black/white check valve.
Will try it directly at the manifold with the check valve removed.
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bakemono
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Re: injection cleaning vacuum lines

Post by bakemono » Fri Nov 01, 2019 5:13 pm

Just to clarify, it looks like #1 or #3 are connected to the intake boot in your pic. But maybe that's only an illusion, I'm not sure if M30s have lines connected outside the throttle body now that I think about it...

Definitely try without the check valve though

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635sharknose
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Re: injection cleaning vacuum lines

Post by 635sharknose » Fri Nov 01, 2019 5:42 pm

#1 and #3 both go to the purge valve
#2 goes to the check valve which is closest to the manifold, just before the throttle valve.
#1 and #2 come from the temp switch
#3 comes from the charcoal canister (#4)

There is also one which comes from the FPR, it is located just an inch left from where I placed the #1.
It is connected to a hose pillar on the bottom of the manifold.
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1987 635CSi Bronzitbeige

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635sharknose
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Re: injection cleaning vacuum lines

Post by 635sharknose » Fri Nov 01, 2019 5:54 pm

Found it! The line which comes from the FPR sucks very strong. You were right just from the beginning! Thanks for the help!
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1987 635CSi Bronzitbeige

Jim Con
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Re: injection cleaning vacuum lines

Post by Jim Con » Wed Dec 25, 2019 8:56 pm

I have always disconnected the white nylon line that comes from the cabin temp sensor, it is under the manifold and you need a hose that fits that nipple.


Last bumped by 635sharknose on Wed Dec 25, 2019 8:56 pm.

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