High idle and BOV problems

[95redTSI]

Alright well I just picked up my 95 TSI and I am having a couple problems with it. First off the car runs great when I don't boost it up, after I do spool it up and come to a stop the car has a really high idle. It will fall back down slowly but it stays at like 2500 rpm for a minute. I think that the BOV is messed up because I don't hear anything coming from it and the car drives fine if I don't spool it up. I think it has a 1G BOV on it but I am not sure. I was thinking about getting a new one but I don't know which one to get because I am still learning about the car. Also the car has an atmospheric dump on it and I don't know what the hell that is. All i know is that there is some weird pipe that comes off the manifold and basically looks like a open header. Mods on the car are T28 turbo, FMIC, injectors, fuel pump, 3 inch exhaust no cat, etc... What are my options on changing the BOV? Any ideas or feedback would be great.
thanks

 

[dalatinromeo]

Are you venting???

 

[95redTSI]

to be honest I really don't know what that means. I am not used to these cars at all. I just put my cobra away so I could drive the TSI in the winter.
thanks

 

[dalatinromeo]

Go to your car and look at your bov. If their is no return tube from your bov to your intake then your are venting. Which is bad, which ultimately could be causing your idle problems.

 

[andymoraitis]

Typically, a vented BOV will cause the opposite issue of what you're describing. Instead of the idle rising and then falling back or "surging", the car will want to stall since metered air is not being returned through the intake tube. For the most part, you may want to have a diagnostic scan performed at a local Autozone and see if any error codes come up. Usually, these will be related to the ISC motor on the throttle body. These can still function partially and not trip a code, but still cause the surging you're experiencing. As a secondary step, you may also want to check the BISS screw on the throttle body and make sure that it hasn't backed out or lost the O-ring that helps it seal properly.

As far as the BOV goes, a 1G unit will hold fine to about 19-21 psi and should do well for your purposes. If you have a chance, take a picture of your BOV and post it so we can have a look and identify it for you.

Hope that helps,

Andy

 

[oldman]

Typically, a vented BOV will cause the opposite issue of what you're describing. Instead of the idle rising and then falling back or "surging", the car will want to stall since unmetered air is not being returned through the intake tube.

Metered. What's up Andy?

 

[1eyedtalon]

not too sure on this but i had an idle problem and it was just a leak in the vaccum line that went from the bov to the intake manifold. not sure if it will help but thought i would throw in some opinions.

 

[95redTSI]

Thanks for all the info. so far, i am going to try and take a picture of it this afternoon. I am pretty sure that it is not venting, I remember seeing a line going from the BOV to the intake. I will try and get a pic. up later.
thanks again

 

[dalatinromeo]

Thanks for all the info. so far, i am going to try and take a picture of it this afternoon. I am pretty sure that it is not venting, I remember seeing a line going from the BOV to the intake. I will try and get a pic. up later.
thanks again

no problem. keep us posted