Vacuum at auxiliary valve hose help

[ADV_rider]

Hi guys, I just got my w116 and between several other things, I noticed that one of the two connections for vacuum, on the aux valve hose, has been blocked with a screw.

Anybody knows where these vacuum lines go to?

This is the hose.. https://www.autohausaz.com/search/product.aspx?sid=wlrk5z3jxfve4batsdg4vqnw&partnumber=1000941191

I took a picture, but don't know how to insert.

Thanks in advance.

[jbrasile]

ADV_rider,

What year is the car?

The hose was modified at some point but basically you have the larger connection going to the top of the WUR and the smaller one feeding the idle compensation valve for the a/c.

Here is a picture of my 78 450SEL Euro, if your car is a US model depending on the year and VIN, the smaller connection feeds a temperature vacuum switch that retards timing during warm up.



Let us know if this helps.

Tks

Joe

[ADV_rider]

ADV_rider,

What year is the car?

The hose was modified at some point but basically you have the larger connection going to the top of the WUR and the smaller one feeding the idle compensation valve for the a/c.

Here is a picture of my 78 450SEL Euro, if your car is a US model depending on the year and VIN, the smaller connection feeds a temperature vacuum switch that retards timing during warm up.



Let us know if this helps.

Tks

Joe

First of all... WOW, WOW , WOW... I did see your thread about your engine cleaning... But hats off!

Thank you... I'll check it as soon as I can get into the car.

It's a 1977 and its supposed to be Euro, manual a/c and velour seats. But it has us spec bumpers... I assume it maybe was Americanized.. S
Is there any way to confirm if its an Euro?

[jbrasile]

Tks ADV-rider

Manual a/c and velour confirms it is an Euro. Do you know if the car was ever registered in the US? There are 2 possibilities for the US bumpers:

1) Car had an accident at some point and previous owner could not locate Euro bumpers in Mexico and resorted to a US dealer or supplier, which probably told him Euro bumpers were not available in the US... not true...

2) Car was Federalized at some point and registered in the States. If that is the case they may have installed a catalytic coverter, air pump and modified to vacuum lines to meet emission standards, that would include cancelling the a/c compensation system and using that vacuum port to feed the above mentioned vacuum temp valve.


Tks

Joe

[Bandolero]

It goes to the Air Con switch (valve), I don't know the correct name but it is on the firewall on the v8s and on the LHS on the six cylinder cars.
It is used to increase the rpm when the A/C is turned on (this makes up for the drag of the compressor thereby keeping the rpm the same. (At idle)
It works by "dumping" the vacuum (when you turn the A/C on) to the inner part of the vacuum advance pot and this then increases the timing (at idle) to make the car idle faster.
This is why (with all the vacuum pipes connected properly), you time the v8s to 0 (TDC) with the aircon OFF.
I think the 6cyl is the same.
If this feature is disconnected, you have to have the timing set to about 10 degrees advanced.

[jbrasile]

Bandolero,

That only applies if the car is Euro. US emission spec cars from a certain VIN onward do not have idle compensation, as I mentioned the connection for  the line that feeds the firewall valve is used to supply vacuum to the  retard switch.

Tks

Joe

[Bandolero]

Our Australian delivered cars have this feature as well.
My 6cyl and the 6.9 which are both Aussie delivered have this feature which does work very well. Modern cars do this by the computer but ours were done mechanically.

[jbrasile]

Bandolero,

All 116's have idle compensation except for certain US versions. And yes it works perfectly! Starting with 126's Mb started using   and electric idle compensating valve that sometimes goes bad and is $$$ to replace...

Tks,

Joe

[Bandolero]

Haha, that'd be right. Go modern and up go the $$$$$$$ 

[ADV_rider]

Tks ADV-rider

Manual a/c and velour confirms it is an Euro. Do you know if the car was ever registered in the US? There are 2 possibilities for the US bumpers:

1) Car had an accident at some point and previous owner could not locate Euro bumpers in Mexico and resorted to a US dealer or supplier, which probably told him Euro bumpers were not available in the US... not true...

2) Car was Federalized at some point and registered in the States. If that is the case they may have installed a catalytic coverter, air pump and modified to vacuum lines to meet emission standards, that would include cancelling the a/c compensation system and using that vacuum port to feed the above mentioned vacuum temp valve.


Tks

Joe

Supposedly the car was bought by the Philipines ambassador at the Vatican. There are original service receipts from MB Rome.  Then taken to Hawaii and then to Florida by the original owners son, and then inherit by the  nephew in FL..
I bought it in Florida and the tittle prev registration is march 92..

Sincerely this wasn't important, just interesting, but the car condition. it has only 107,000 kilometers (67,000 miles)! The instruments are all kilometers ... But it's kind of awkward it has the us bumpers and headlights!

I don't think it has a cat, but I will check out. I don't know how or what is the air pump.. Where should I look for it?

I flew to Orlando and drove the car like 1300 miles to Laredo, Tx... Car was perfect... Except for a leak on the left manifold to exhaust,  and then the most obnoxious thing heat always coming on from vents! (A/C not working.

I  found the white plastic between the vacuum element and heater inlet valve is broken, I assume this is what is causing the hot air.

[ADV_rider]

Is part #2a in this pic, the switchover valve that it should connect to?

[jbrasile]

ADV_rider,

No question you have an Euro, however since it was registered in the US in the past they probably had to Federalize it, hence the US bumpers and headlights.

Florida did not have smog tests back then as far as I know but maybe Hawaii did, most likely you do not have a cat. The air pump would be located under the alternator on the passenger side of the engine. Its function was to reduce emissions by pumping air into the exhaust manifold. Looking back now we realize how crude and archaic emission controls were in the 70's and 80's...

As for hot air coming out of the side vents, the heater valve's default position is open so if there is no vacuum to close it,  hot water will circulate through the heater core and you will get hot air blowing through the side vents. This problem can probably be solved by replacing the broken vacuum line or the valve itself.

Sounds like you got a great car with a very interesting pedigree!  Post some pictures when you have a chance, I have been traveling  to Mexico City from time to time over the last 20 years and have yet to see a 116.

Tks

Joe

[Bandolero]

The pics aren't showing. 

[ADV_rider]

ADV_rider,

No question you have an Euro, however since it was registered in the US in the past they probably had to Federalize it, hence the US bumpers and headlights.

Florida did not have smog tests back then as far as I know but maybe Hawaii did, most likely you do not have a cat. The air pump would be located under the alternator on the passenger side of the engine. Its function was to reduce emissions by pumping air into the exhaust manifold. Looking back now we realize how crude and archaic emission controls were in the 70's and 80's...

As for hot air coming out of the side vents, the heater valve's default position is open so if there is no vacuum to close it,  hot water will circulate through the heater core and you will get hot air blowing through the side vents. This problem can probably be solved by replacing the broken vacuum line or the valve itself.

Sounds like you got a great car with a very interesting pedigree!  Post some pictures when you have a chance, I have been traveling  to Mexico City from time to time over the last 20 years and have yet to see a 116.

Tks

Joe

Thank you. I've been searching some threads  and I can confirm my car doesn't have an air pump.

I don't know how to insert pictures into a thread and didn't  find any help on how to. But his is my car, there are some pics on the ebay add I purchased from:
http://cgi.ebay.com/ebaymotors/450-SEL-/300871820109?_trksid=p3984.m1497.l2649&ssPageName=STRK:MEWNX:IT&forcev4exp=true#ht_500wt_1064


I was lucky, it went under the radar because there where like 3 6.9s offered at the same time.

Funny what you mention about not many W116s in Mexico.... After I got mine I have seen > 4 in a few weeks.  I'm in the Mexican MB club and there are none..

[ADV_rider]

The pics aren't showing. 

I thought it was only my iPad not showing them. 

I tried to link a picture posted by zeppelinboy .. Called blowup #2

http://forum.w116.org/mechanicals/emissions-thread-update-name-these-parts/msg21245/#msg21245