Need help! Disconnecting the Return fuel line from filter, may have gotten wrong line

I tried to make a small mod that a friend told me about on my 96 Passat...cut the fuel line (nearest one to the passenger fender) coming out of the fuel filter and going into the 'T' fititng, then I plugged both ends. He did this on his 97 Passat and the result was much less smoky start-ups and a little better fuel economy, supposedly due to the fact that the line in question runs fuel back out to the exhaust. Mine, it seems is sending fuel to the cooling system...supposedly there is also a How To about this simple mod on TDIclub.com, but there's som mcuh stuff I can't find it. If it's acutally sending fueld to the cooling system, then how do I fix that? Un-doing the mod is easy....Any help would be greatly appreciated.
Jeremy

Picture showing what you did? We need to see what you did.

The only line you cut on a 96 Passat with the 5th injector is the one going to the solenoid mounted on the side of the airbox. Block it off with a bolt and clamp it.