IanM

I pressure tested my intake, and found the vacuum port under the throttle body is not holding pressure. The vacuum hose from this port goes to the two-prong thermo switch under the intake manifold, and in turn the hose from the thermo switch goes to the diaphragm at the carbon tank control valve.

It appears that when the engine is cold, the diaphragm is closed and the recirculation vent from the gas tank to the intake is closed. As the coolant heats up the thermo switch opens, which opens the diaphragm and allows the gas tank to vent into the intake just upstream of the turbo.

I have previously replaced the thermo switch, in an attempt to correct this intake leak. At this point I've decided to just plug off the port under the throttle body, and vent the carbon tank control valve diaphragm to atmosphere. With the diaphragm vented (instead of being under a vacuum) it only seems to take a small amount of pressure to allow fumes to vent through it.

Does anyone know of a problem with doing this? So far I can't smell anything nasty, and my idle is much improved with the intake leak fixed.

Scott H

Do you have to get the car inspected? If not just rip all that crap out of the engine bay, take off the DS inner fender liner and remove the charcoal canister and lines, and then trace the one line back to the fuel tank and hack it off near the tank. I as well as many others have done this and never got any fumes in the garage or anything like that. Plus it cleans up the engine bay nicely. For more directions search for "fuel vapor purge delete"

IanM

Thanks!