Auxilary Air Valve 77 3.0 ROW vs 78 U.S. SC

Argeo · 05-12-2003, 05:01 AM

Hi, I tried tinkering with my auxilary air valve (AAV) to no prevail. It started a bit better but didn't shut all the way when warmed up. Now I need to buy a new one. Where my car is a ROW 77 3.0, will it have the same AAV as the 77 or 78 U.S. models?

In case it is not, I will be posting another message to find out parts dealers around Germany and Switzerland incase I need to go that route.

Thanks.

1980SC · 05-12-2003, 06:29 AM

I assume you mean AAR. Don't order an AAV unless you want one of these :

I'm sure the USA '78-'79 AAR would work fine on your 3.0. I doubt they could have changed much. As long as the heating element in yours is working, you should be able to adjust it properly. Bend the bi-metallic strip so it does close completely when hot. It doesn't need to be open very much to raise your cold idle rpm.

If it doesn't raise your cold idle like it should, then you may have a vacuum leak, or your mixture is incorrect. A new AAR may not work any better.

Rob
1980SC

ChrisBennet · ChrisBennet's Garage

I think he meant AAR Auxilary Air Regulator.
-Chris

Argeo · 05-12-2003, 09:48 AM

Hi,
No, I meant AAV otherwise known as AA Device or AA Regulator unless the Bosch Solving CIS problems has the wrong name for it. The valve when cold is less than a 1/4 open. I tried bending the Bimetal spring a bit. The car didn't start much better but when hot the RPM's are at about 2K, so I don't think the valve is shutting enough now. Some have said that there valves are 1/2 way open cold. Where mine was less than a 1/4 open I am assuming that is the problem. The symptoms were all there. It took numerous starts to get to run, when it did run not all cylinders would fire as a result of too much gas pouring in without enough air causing fouled plugs. It also would backfire out of the pipe at startup which I think means the car is running rich. Before, when the car did warm up it ran great which meant the valve was shutting. Now the car still doesn't start that great but at least the plugs are not getting fouled up. I still do not think the valve is open enough. It is only a bit more than a 1/4 open now cold. Now the valve is not shutting all the way so the engine is sucking in more air at operating temp which explains the high RPM's at idle (2k). I also was not able to control the idle from the throttle body before, I can now but not enough to compensate for the overflow of air coming through the unclosed valve at operating temp. I may be able to get my hands on a 78 SC to try.

Thanks for your help.

Argeo · 05-16-2003, 05:48 AM

Problem solved. It was the AAV. I tried using the valve on my neighbor's car and it did not work. Well after sadness set in, I put my now tampered with valve back on so I could at least drive to a shop for fixing. By tampered I mean I pulled the valve apart and tinkered with the bypass line. Anyways, I called a local Porsche shop and the guy said it looked like a cold start valve problem. I went home that night and went to test the Thermo time switch and noticed the connection was off. It must have fallen off somehow when I put the motor back in recently. Anyways, I connected up and the car started right up. This actually happened two days ago but I did not want to report incase in was a fluke.

Anyways, I still need to back off the WUR a little bit. It seems to be running a bit rich. After that, adjust a slighly loose valve hopefully on the intake side and fool around with the shift linkage and I will be done. To sell or not to sell, that is the question. I am not sure I can take anymore abuse.

Thanks to all that have helped me.