Vacuum fitting part # help?

Post here for mechanical and engine topics such as fuel issues, transmission problems, rough idle, exhaust, electrical issues, etc

Moderators: GRNSHRK, ron, bfons

Post Reply
songzunhuang
Platinum Member
Platinum Member
Posts: 1224
Joined: Fri Aug 14, 2015 10:04 am
Location: Silicon Valley, CA
Contact:

Vacuum fitting part # help?

Post by songzunhuang »

In my 84 633, there a fitting on the underside of the intake manifold that connected to a hollow plastic tube. The fitting is a small diameter hose with cloth outside re-enforcement. There’s a tiny metal clamp holding the short section of hose onto the manifold and the the hollow plastic tube (whiteish color) slips into the hose section.

Does anyone know the description or part number for that hose and clamp?

Mine is disentigrating and I am sure it’s not holding the vacuum correctly as it doesn’t fit around the plastic tube so well. Maybe this is part of my rough idling issue?

Thanks in advance for any help.
-----
Song Huang
1984 633CSi
Last 7 of VIN: 6997383
songzunhuang
Platinum Member
Platinum Member
Posts: 1224
Joined: Fri Aug 14, 2015 10:04 am
Location: Silicon Valley, CA
Contact:

Picture worth a Thousand words

Post by songzunhuang »

OK, no reply possibly because no one can tell what I am talking about from my prose? Here are some pictures to help.

Here's what you see from above. The plastic vacuum tube is clearly in view and you can see where it goes into the hose in question.
End of hose seen from above.
End of hose seen from above.
Screen Shot 2017-10-25 at 5.12.53 PM.png (1.52 MiB) Viewed 7024 times
From below you can see the hose connection to the manifold where it is secured by an Oetiker clamp.
Hose and clamp from below.
Hose and clamp from below.
Screen Shot 2017-10-25 at 5.13.40 PM.png (1.73 MiB) Viewed 7024 times
Does this help to generate any ideas? Thanks for any guidance.
-----
Song Huang
1984 633CSi
Last 7 of VIN: 6997383
User avatar
sansouci
Platinum Member
Platinum Member
Posts: 1850
Joined: Mon Jul 08, 2013 10:52 pm
Location: Southampton NY

Re: Vacuum fitting part # help?

Post by sansouci »

I've got the same thing and always thought it was part of a temperature sensor.
Sansouci
84 E24 633Csi Auto, Bronzit/PearlBeige 6997510
93 E32 740il M60 Auto, Alpenweis/Ultramarine
60 528i M30 5-speed Green/Beige (crushed)
71 240Z 4-speed White/Blue (rusty & sold)
65 396 Chevelle 4-speed, Marina Blue/Black (stolen)
User avatar
hornhospital
Platinum Member
Platinum Member
Posts: 2929
Joined: Sun Jul 11, 2010 6:46 pm
Location: Silverhill, AL
Contact:

Re: Vacuum fitting part # help?

Post by hornhospital »

Isn't that the "sniffer" hose for the interior temperature sensor? It uses carefully metered-down engine vacuum to draw air across the sensor above the driver's footwell.
Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'85 325e "Hazel Ann"; '95 M3 "Ashlyn"
songzunhuang
Platinum Member
Platinum Member
Posts: 1224
Joined: Fri Aug 14, 2015 10:04 am
Location: Silicon Valley, CA
Contact:

Re: Vacuum fitting part # help?

Post by songzunhuang »

hornhospital wrote: Thu Oct 26, 2017 2:50 am Isn't that the "sniffer" hose for the interior temperature sensor? It uses carefully metered-down engine vacuum to draw air across the sensor above the driver's footwell.
Hmm, these responses are making me think that this has nothing to do with my rough idle.
So why does interior air get drawn into the intake manifold? Is it creating a vacuum just so air gets drawn over a sensor inside the car?

While experimenting, I did pull this vacuum tube while the car was running and it didn't make much difference.
-----
Song Huang
1984 633CSi
Last 7 of VIN: 6997383
User avatar
hornhospital
Platinum Member
Platinum Member
Posts: 2929
Joined: Sun Jul 11, 2010 6:46 pm
Location: Silverhill, AL
Contact:

Re: Vacuum fitting part # help?

Post by hornhospital »

songzunhuang wrote: Thu Oct 26, 2017 6:06 am

So why does interior air get drawn into the intake manifold? Is it creating a vacuum just so air gets drawn over a sensor inside the car?

Exactly. It ensures there is airflow over the interior temperature sensor so the heat/AC system can adjust. Otherwise the interior temperature would fluctuate widely, because the sensor is small and rather buried in the dash underpanel.
Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'85 325e "Hazel Ann"; '95 M3 "Ashlyn"
User avatar
sansouci
Platinum Member
Platinum Member
Posts: 1850
Joined: Mon Jul 08, 2013 10:52 pm
Location: Southampton NY

Re: Vacuum fitting part # help?

Post by sansouci »

But after searching realoem, I couldn't find that part or where it connects to under the dash.....
Sansouci
84 E24 633Csi Auto, Bronzit/PearlBeige 6997510
93 E32 740il M60 Auto, Alpenweis/Ultramarine
60 528i M30 5-speed Green/Beige (crushed)
71 240Z 4-speed White/Blue (rusty & sold)
65 396 Chevelle 4-speed, Marina Blue/Black (stolen)
User avatar
zinnocoupe
Posts: 506
Joined: Fri Sep 19, 2014 12:57 am
Location: Vancouver BC

Re: Vacuum fitting part # help?

Post by zinnocoupe »

Song, I would suggest just getting rid of the old frayed hose section and oetiker clamp and replace it with a section of rubber hose with two hose clamps, one for the manifold end and one on the sniffer hose. I think I did that on my car when I first bought it and replaced every rubber fuel, vacuum etc line I could find. Since then I've never had any issues at all with leaking fuel or vacuum that seem to plaque these cars. I've just started the same procedure on my new e12. Some of the fuel lines near the tank are literally crumbling in my hands.
Image
Image
1979 Euro 635ci no longer a basketcase, just a running rust bucket!
1977 530i Partially restored and running now!
1987 635csi 60K KM Garage Queen
User avatar
86_6series
Platinum Member
Platinum Member
Posts: 1069
Joined: Mon Apr 02, 2007 10:08 pm
Location: West Nyack, NY

Re: Vacuum fitting part # help?

Post by 86_6series »

Sensor-Location.pdf
(168.71 KiB) Downloaded 238 times
sansouci wrote: Thu Oct 26, 2017 7:26 pm But after searching realoem, I couldn't find that part or where it connects to under the dash.....
86-635CSi
96-MB C220 SOLD
98-740i
71-Continental MK3
User avatar
hornhospital
Platinum Member
Platinum Member
Posts: 2929
Joined: Sun Jul 11, 2010 6:46 pm
Location: Silverhill, AL
Contact:

Re: Vacuum fitting part # help?

Post by hornhospital »

Thank you, sir! I thought I was imagining things...and I really didn't want to drop the under panel to prove there was such a thing. I still haven't located it in the online charts (Realoem.com)
Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'85 325e "Hazel Ann"; '95 M3 "Ashlyn"
songzunhuang
Platinum Member
Platinum Member
Posts: 1224
Joined: Fri Aug 14, 2015 10:04 am
Location: Silicon Valley, CA
Contact:

Interesting Observation

Post by songzunhuang »

zinnocoupe wrote: Sun Oct 29, 2017 5:35 am Song, I would suggest just getting rid of the old frayed hose section and oetiker clamp and replace it with a section of rubber hose with two hose clamps, one for the manifold end and one on the sniffer hose. I think I did that on my car when I first bought it and replaced every rubber fuel, vacuum etc line I could find. Since then I've never had any issues at all with leaking fuel or vacuum that seem to plaque these cars. I've just started the same procedure on my new e12. Some of the fuel lines near the tank are literally crumbling in my hands.
So Zinnocoupe, I did exactly what you said. I came across an old Volvo part that I had when I was replacing a bunch of vacuum connections. As it turned out, it looked like it could replace the old frayed BMW part pretty well. It served a very similar function on the Volvo. Here's the old BMW part on the left compared to the new Volvo part.
This Volvo part could very well serve the purpose of the BMW part on the left.
This Volvo part could very well serve the purpose of the BMW part on the left.
Screen Shot 2017-10-31 at 5.37.10 PM.png (1.18 MiB) Viewed 6904 times
OK, so off came the old crumbly hose and on went the Volvo part.I must say it fit well and almost looks like it was designed for it!
Volvo hose fitting installed in BMW intake. Looks good!
Volvo hose fitting installed in BMW intake. Looks good!
Screen Shot 2017-10-31 at 5.37.25 PM.png (689.39 KiB) Viewed 6904 times
When I was messing with the old crumbly part, I noticed something inside and decided to cut it apart. Surprise! There is an aluminum restrictor of sorts in the hose with a tiny hole in it. I guess only a slight vacuum is needed for this function. Of course I don't have that in the new Volvo part. I guess if I wanted, could jam it in the hose. For now, I'm just going to see how the Volvo part does.
Restrictor part that was inside the old BMW hose.
Restrictor part that was inside the old BMW hose.
Screen Shot 2017-10-31 at 5.37.43 PM.png (1.01 MiB) Viewed 6904 times
If nothing else, interesting to note.
-----
Song Huang
1984 633CSi
Last 7 of VIN: 6997383
User avatar
hornhospital
Platinum Member
Platinum Member
Posts: 2929
Joined: Sun Jul 11, 2010 6:46 pm
Location: Silverhill, AL
Contact:

Re: Vacuum fitting part # help?

Post by hornhospital »

That aluminum insert with the tiny hole is the "carefully metered" part I spoke of. It really needs to be in the hose.
Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'85 325e "Hazel Ann"; '95 M3 "Ashlyn"
Post Reply