CIS - Confusing Injection System - How did it run?

CIS Guru's please advise.

While I'm waiting on a couple more engine components to get back I thought I'd try to get the CIS system ready for cleanup and checkout but..
I have found that many of the components that appear to need to be there are not and I can't believe the car ran as well as it did without them.

The first pieces missing are the auxilliary air valve, auxilliary air regulator, and thermo valve and associated hoses. (The throttle body and cold start valve where these components have vacuum lines from are not even capped - Haynes Manual pg 263 Figure 11.16 items 2,3,& 4 gone and not connected)The cold start valve is there and was hooked up electrically but no hoses are attached. The EGR and diverter valves are also gone(items 7 and 8). The WUR is hooked up electrically but again the hose connections are capped except for gas in and out.

Item 9, the vacuum control valve, is still present and configured as in the Haynes manual as best I can tell. However the ?? Throttle Positon unit? (page 70 figure 2.57) is in place but the small hard plastic hose on the back is cut as is the rubber hose also going or coming from this device.

Sorry for the long essay but here are my questions:

How could this ever have run?

I would like to put it back right, with the exception of the air pump which is also gone. I assume all of these are required components?? The EGR once existed as this was originally a California car.

I have the Bosch fuel injection book but can find no reference to the ? throttle position gizmo? What does it do?? Where shoulkd the hard plastic line and rubber line go?

Where is the idle air bypass used to adjust curb idle? (pg 109 Bosch)

Lastly, anybody have any good pictures of a unit set up correctly that they would like to share with me??? Bosch and Haynes are pretty good but they need a wider lens.

As always Thanks for your help...

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78 3.0L/3.2L CIS 911SC

To start with buy these two books, How to tune and modify Bosch Fuel Injection by Ben Watson and Bosch Fuel Injection & Engine Management by Charles O. Probst. These are great books and will take the mystery out of CIS. You can find them at Borders or Barnes and Noble....TargaEuro

The major function of most of the items that you have missing is to assist in cold starting. It's concievable that an engine with a rich mixture setting could start and run without all of those pieces in place. Massive vacuum leaks though.

The Haynes manual has the best complete diagram for your '78 system. I believe it even shows the EGR valve installed on CA cars. I don't have the manual in front of me, but I'll take a look at it later tonight.

You're going to have to round up your missing components. New costs are outrageous, but you might get lucky finding used stuff. There was somebody on the Pelican Parts board selling CIS stuff recently. Make sure you get the right parts for your year, the CIS components seem to vary from year to year.

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Bill Krause
'79 911SC Euro

The Probst book is good, but it is not specific to Porsche, so there are some details missing.

I can help you with part no's for your missing devices. I've also got a digital camera and a fairly well running CIS system to photograph. No EGR valve though.

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Bill Krause
'79 911SC Euro


[This message has been edited by wckrause (edited 04-03-2001).]

Thanks guys, I'll check the books tonight as there is a B&N close by.

I'm not hung up on getting the EGR valve in place, but I think the overall performance would be better to get most of the components back. I can start the search through Pelican and others going forward.

What is the purpose of the diverter valve and the throttle postion gizmo? I somewhat understand in general the cold start valve, warm up regulator, EGR, thermo valve, etc. from reading other posts and doing some searches.

Bill, The pictures would be a bid help with the device routing as well as mounting. Thanks All...

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78 3.0L/3.2L CIS 911SC

From memory, the 78SC CIS system had fewer pieces and vacuum hoses than say the 80SC. I believe the EGR valve wasn't even on the 78. Again don't quote me, but I do remember the Hanes manuel showing a difference between the early late SCs.
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Paul
78SC Targa

The 80-83 SC's (US) had the Lambda system with oxygen sensor. They didn't have the thermovalve. EGR was only on CA cars, I think.

I'm going to have parts of my engine dismantled for a valve adjustment this weekend. It will be a good time to hunt down and photograph CIS components.

What parts do you have, and what parts do you know are missing?

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Bill Krause
'79 911SC Euro

Bill,
Items I do have:
WUR, Cold Start Valve, Vacuum Control, Distributor with vacuum unit.
In the Haynes Manual page 263 fig 11.16 these would be items 5,10,9 & 6 respectively.

Items I don't have and were not on the car, even though it ran very well before I took the engine out:
Auxilliary Air Valve, Auxilliary Air Regulator, Thermo Valve, EGR Valve, Diverter Valve.
Again in Haynes(Same reference) this would be items 2,3,4,7 & 8 respectively.

No power brakes on this car. Also the air pump and all of it's components were not on the car. The injector ports were capped with ball bearings and a fitting on each cylinder.


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78 3.0L/3.2L CIS 911SC

Adam Roseneck has/had CIS parts for sale from his '78SC. I believe he still has many parts left. Look over on the "for sale" board.

Most of the jusnk piled on top the CIS is emission and cold start related. If you were to strip all this off the system becomes quite simple in its function. Apparently the P.O. did just that.

RarlyL8's right, it's all cold start and emissions. The part that bugs me is all of the vacuum leaks you've got that aren't plugged up. I think, if this were my car, I'd try to find an AAR and AAV, and get that all plugged into the air box correctly. Next, I'd worry about the vacuum limiter (decleration valve), thermovalve, WUR vacuum connections.

Also, get a pop-off valve, I think you're going to need one.

I've got a thermovalve you can have. I got my old one working while I was waiting for a new one to get delivered to my local Porsche dealer.

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Bill Krause
'79 911SC Euro

Thanks for all your help fellas.
I'm going to sleep on it and see where I go from here. I e-mailed Adam to see if he might still have his CIS system for sale.
My initial feelings are to get the AAV, AAR, Thermovalve and diverter valve and install them like fig 11.17 Haynes for 79 CIS. I'll just have to figure out where/how to mount the devices. It sure would be nice if they had put the hose sizes in the manual as well. Thanks Again for all your support.

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78 3.0L/3.2L CIS 911SC