EVAP Valve question

smithy850 · Post by **smithy850** » 29 Nov 2005, 14:03

I've had a CEL on in my '98 S70 for a while now. I can't remember the exact code, but it involved the air pump. My air pump is getting louder (not gone yet though!) and I was under the impression that a faulty SAS valve was the cause of both the pump deterioration and the code. However, on a visit to the dealer for a different, much more crucial problem, the tech looked into the code for me and told me I have a faulty EVAP valve.

Enough of that babbling, now the question. Is the EVAP valve part of the same system and can it cause the same code? Also, would a faulty EVAP act similarly to a vacuum leak? The reason for this question is that I have performance issues that I wouldn't relate to an air pump issue (ie: rough idle, poor pickup, etc.)

Thanks for any input!

White850Turbo · Post by **White850Turbo** » 01 Dec 2005, 06:51

I think there are two seperate issues at play here. First off, the evap valve is a relatively common failure and is not really very expensive to replace. You can do it yourself in about 15 minutes tops. The new part is updated to prevent a repeat failure.

The problem with the air pump sounds like you may have some torn elbows in the system. There are several of them; I'd carefully inspect them and replace if necessary. They can be the cause of codes for the air pump system and can also be to blame for poor performance. The absolute best way to tell if there is a leak in the system is with a vacuum gauge hooked up to the vacuum tree on the throttle body. It should read between 18 and 21 inHg at idle. The best way to find the leak is with an unlit propane torch; when you get near the leak, the idle speed will rise.

smithy850 · Post by **smithy850** » 01 Dec 2005, 11:14

Thanks for the input. I swapped out the EVAP valve last night, 15 minutes exactly. I did notice that one of the vacuum lines I had to pull was a little flaky on the outside. It didn't crumble on me when I was pulling and pushing on it though. On visual inspection, the others seem OK, but I will test further. When using the vacuum guage on the vacuum tree, does it matter which port you use?

White850Turbo · Post by **White850Turbo** » 01 Dec 2005, 16:13

smithy850 wrote:Thanks for the input. I swapped out the EVAP valve last night, 15 minutes exactly. I did notice that one of the vacuum lines I had to pull was a little flaky on the outside. It didn't crumble on me when I was pulling and pushing on it though. On visual inspection, the others seem OK, but I will test further. When using the vacuum guage on the vacuum tree, does it matter which port you use?

No, any of the empty ports will work.