air valves

[Boydskyking]

I have a question about the air valves on my 1980 911 3.0. The Bentley manual shows by pictures the deceleration valve right next to the Auxiliary air regulator with the Auxiliary air valve behind the engine.The CIS primer on the Rennlist list shows the Deceleration valve behind the engine and the Auxiliary air valve next to the Auxiliary air regulator. My question WHICH IS RIGHT

I want to let all you guys know that I really appreciate all the help I have received from you in the pass,I really really appreciate it
Thanks

[Jim Williams]

The location and the type of factory Decel valves changed between '79 and '80. I don't own a Bentley Manual, but I assume it shows the '80 and later. The CIS Primer shows, in at least one place, the style and location of the Decel valve up through '79, so I guess you might say they are both right.

[Bob Kontak]

Believe the later decel valves look like cadmium plated flying saucers - similar to the AAV - and sit to the right (passenger side) of the AAR but a little further back (towards front of car) and below the AAV.

I can get you a pic of the later setup but I think a search on "911SC engine" in google will show you both setups.



I do noth know

[Jim Williams]

Actually now that I look further, a page on the Primer site shows both styles:

CIS Primer for the Porsche 911

and see "Vacuum Diagrams" in the Menu.

[Boydskyking]

Go back to the CIS primer and click on the Parts ID window and scroll all the way to the bottom of the page and you will see actual pictures of and CIS system sitting on an engine with the valves reveresed from what they are in the vacumn diagram, Which is right


Thanks

[Bob Kontak]

See post 7. That is a 1980 SC.

Wiring all the gauges in a 911 SC

[Boydskyking]

Thanks guys I know which way they go now

[Jim Williams]

CIS primer
Go back to the CIS primer and click on the Parts ID window and scroll all the way to the bottom of the page and you will see actual pictures of and CIS system sitting on an engine with the valves reveresed from what they are in the vacumn diagram, Which is right

Just a clarification:
The parts diagram is from a catalog which has parts for the '74 - '89. The diagram covers CIS parts from years '74 though '79, and is not a diagram of one particular year. If you will notice, part 20 is the throttle control pressure regulator, the last year for which is '75. Yet the AAV, shown in this same diagram, did not appear until '76. Number 24, the thermovalve, did not appear until '77. The diagram was used only to order parts from; you won't find all these parts on any one year's CIS system.

The photo at the bottom of that page is of a conglomeration of various year parts, set up for a demonstration, and not intended to represent any certain year. As far as the exact location of the AAR in this photo, it really makes no difference to the CIS which valve is in which place, as long as they are both there.

[paj]

I have 80SC also, does yours have air nipples on both of them? I finally hooked the vacuum hose to the bottom one next to the AAR. The vacuum hose was plug when I got the car.

[Jim Williams]

Originally Posted by paj

I have 80SC also, does yours have air nipples on both of them? I finally hooked the vacuum hose to the bottom one next to the AAR. The vacuum hose was plug when I got the car.

Not sure of who the question was directed to, but both the valves won't have nipples. The one with the nipple is the deceleration valve, and should be on the bottom. The other is the Aux Air Valve (AAV) with no nipple.

[paj]

Here is a photo of my 80SC do you think someone had put the wrong valve on mine? maybe this is the reason why my car is idling high after warming up? I just got this car running after sitting four long years.

[Jim Williams]

Originally Posted by paj

I have 80SC also, does yours have air nipples on both of them? I finally hooked the vacuum hose to the bottom one next to the AAR. The vacuum hose was plug when I got the car.

Originally Posted by paj

Here is a photo of my 80SC do you think someone had put the wrong valve on mine? maybe this is the reason why my car is idling high after warming up? I just got this car running after sitting four long years.

I can't speak to the reason for your high idle after warm up without knowing the basic settings on your CIS, but I can say that whatever you have in the place of the AAR (top component) is not what belongs there. If you can post the Bosch number stamped on it, I can likely tell you what it belongs on.

I know that certain 930 (Turbos) have something that looks like a Deceleration Valve that also may act like both an AAR and a Decel valve. I haven't had anyone confirm this, just a suspicion... If anyone knows the answer, please post it.

[911Freak]

Originally Posted by paj

Here is a photo of my 80SC do you think someone had put the wrong valve on mine? maybe this is the reason why my car is idling high after warming up? I just got this car running after sitting four long years.

My 80SC looks similar to this picture, in that I have a hose/line connecting onto the lower canister from behind the engine, and none on the upper canister's nipple.

When I 1st got my 911 and hadn't read up on the CIS for 911s, I thought both nipples needed to be hooked up (stupid), so, when I plugged the upper nipple my idle jumped high and stayed there until I removed the plug and all went back to normal.

This shows how important it is to understand our CIS injection system, buy the tools/gauges for checking pressure (CIS is all about pressure) and read up on the system here and in your repair manuals.

There could be several reasons for your high idle. To properly diagnose you'll need the gauges and understand the troubleshooting process as it's best done in specific order to produce the desired results.

The good news is CIS is a very good system and once you get a handle on it you'll enjoy it's performance and maintenance

Good Luck!

[Goodie]

I've got nipples on both as well ('80 SC). Completely rebuilt this Fall, plugged the top nipple and now it idles vey high all the time. I'm hoping the removal of the cap on the nipple will allow it to idle as it should. It did idle (relativley) fine before the rebuild.
I've been on lots of forums...everything from chainsaws to washing machines. This is one of the finest out there!!
Thanks everyone for sharing all of your great experiences and advice!

[mercury26]

According to the parts catalog and looking at my own CIS setup, you should have one with the nipple for vacuum (which is the decal valve) and the other that does NOT have a nipple. If you have two with a nipple, then I think some one was messing with your CIS setup in the past.

[Pazuzu]

I think it's a 1980 thing. My 80 has both with nipples, bottom one hooked to vacuum.
The part numbers are:
0 280 160 324 (standard decel valve)
0 280 160 404 (aux air valve, but strange part number)

There is almost nothing on the web about the -404 valve, but it's clear that several (all?) 1980 911SCs have them...

[Pazuzu]

Here's a link with a good picture from a few years ago. It's not perfectly clear in the picture, but in person they're clearly not the same thing (they have a different dish on the face). also, the part numbers, but those are hard to see without everything removed and cleaned up a bit.

80SC vacuum lines

[Pazuzu]

So, Jim, do you have any ideas about the strange AAV? I'll be putting everything together in the next few days, and would like some expertise on it. For now, it will remain unplugged and uncapped, since that's how ever 1980 SC so far has been.

[911Freak]

I spoke about this 80 only issue with a couple of porsche wrenches, they told me the 2 canisters both with nipples is a 1980 only configuration as the CIS system crossed over from older version 78 and 79 to the newer 81-83 configuration. This makes the 1980 configuration unique. The upper canister with the nipple functions similar to a decel valve in which it allows air into the system on decel in conjunction with the emmisions system (distributor advance/retard/0xygen sensor etc)

So in summary, only the 1980 MY SCs will have the double nipple configuration.

The bottom canister being connected to vaccum line and the upper canister's nipple left open.

Great thread for future 1980 SC owners!

Cheers

[Jim Williams]

Originally Posted by 911Freak

I spoke about this 80 only issue with a couple of porsche wrenches, they told me the 2 canisters both with nipples is a 1980 only configuration as the CIS system crossed over from older version 78 and 79 to the newer 81-83 configuration. This makes the 1980 configuration unique. The upper canister with the nipple functions similar to a decel valve in which it allows air into the system on decel in conjunction with the emmisions system (distributor advance/retard/0xygen sensor etc)

So in summary, only the 1980 MY SCs will have the double nipple configuration.

The bottom canister being connected to vaccum line and the upper canister's nipple left open.

Great thread for future 1980 SC owners!

Cheers

According to the Bosch catalog "Gasoline and Diesel Injection Products" (this one is a 1996 issue, and covers all makes and models), the 0 280 160 404 "Auxiliary Air Valve" is for the 78 and 79 Porsche 3.3 turbo engine. That is the only engine Bosch lists this part number for in the years '76 - '83. If there was a substitution of this one onto the 911 from the 930, it must have been done at the factory.

Bosch calls the Deceleration Valve a "Vacuum Limiter" throughout this catalog. It calls the AAR and the AAV both "Auxiliary Air Valves" and doesn't list the 0 280 160 xxx part number at all from '80 through '83, only the 0 280 140 218, which most of us know as the Auxiliary Air Regulator. I have always wondered about this exclusion of the AAV for these years, and I have never heard an explanation.