BobbyT

1. Considering that OBDI doesn't trigger a CEL when the SAI system is faulty, how would one know that the SAI valve had failed?

2. When the valve fails, can it cause engine damage?

3. Rather than removing the entire SAI system, how about just plugging the valve and leaving all in place?

Vorsicht

1. Considering that OBDI doesn't trigger a CEL when the SAI system is faulty, how would one know that the SAI valve had failed?

In my case I had the air box out to replace the fuel filter and saw that the hose from the SAI pump was just dangling. The top of the check valve had rusted off. I could see into the valve and it too was a rusted mess. Short answer, do a visual inspection.

2. When the valve fails, can it cause engine damage?

Not that I'm aware of - it basically just shoots air into the exhaust when it's cold out.

3. Rather than removing the entire SAI system, how about just plugging the valve and leaving all in place?

That is certainly one good option - and easy. Many a 95 993 owners have removed the whole thing (myself included). I was looking for a fun project. And it turned out to be a barrel of monkeys (many hours over several days)!

Here is a pic of my check valve prior to excision.

FlatSix911

Based on my understanding of the system ... the SAI valve only functions during the first 30 to 60 seconds after a cold start to help with emissions ... so nothing to worry about on a 1995 993

simpsoap

A number of us have removed the system all together. I figured this was the best route and followed the advice of other fellow Rennlisters. Was an interesting DIY, and taught me a lot in the process.

Andy