# Restoring a 16V GTI



## Dead Skunk (Jun 18, 2003)

I'm putting a 1991 16V back on the road and returning it to stock configuration. That means I'm taking out the race style header and exhaust and putting back the stock stuff. Since I didn't take the stock manifold out I'm having a little difficulty with a couple of things putting it back together. There's a tube from the manifold that the Bentley calls a CO2 sampling tube. It's clear where it connects to the exhaust, but where does the other end go to? And what goes on that end? Thanks


----------



## where_2 (Jul 21, 2003)

*Re: Restoring a 16V GTI (Dead Skunk)*

the CO sampling tube attaches to the exhaust manifold on the lower end, and usually has a light blue silicone rubber stopper plug attached to the upper end with a fuel injection style hose clamp around it to keep it from blowing off. 
If you were thinking both ends attached to something, you were mistaken. It is for performing emissions testing and sampling the exhaust gasses before they are "fixed" by the catalytic converter. Few shops had the apparatus to hook up to this "test pipe", and most places that test emissions test what you are spitting out, not what your catalytic converter is having to work with.


----------

