Ok, finally took the cover off of the throttle body. Finally found the vacuum tree that everyone has been talking about. Doh! It is starting to show its age.


I only have two vac lines branching off the tree. One of them I replaced last year, hose and elbows. It leads from the vac tree to a solenoid then to an air control valve that injects air into the cat converter through the 2" corrugated silver hose. The control vane is mounted below the engine air filter box.


Next up, the solenoid driving the purple hose.

Unplugged the solenoid from the computer for "Secondary Air Injection Switching Valve A". Computer gave P0413 code and "Circuit Open". This line has a 1" dia air filter thing in the middle of the pipe and leads to a solenoid valve mounted on the top center edge of the radiator fan. Solenoid connects vacuum to the purple line that leads to a 2"x2" round silver thing at the firewall that apparently allows fresh air into the engine.

My rubber parts are in really bad shape there. The tree and all the vac lines will be replaced next week, ASAP. I promise.

Something did change during my drive with this solenoid unplugged. The car still stalled a predictable distance away from where I started. But, it restarted right away and continued on, a couple of sputters but ok.


EVAP SYSTEM.

I didn't realize this, but the Evap system doesn't connect directly to the vacuum tree. It has a larger 1/4" dia port on the drivers side of the engine and has a larger black rubber pipe leading towards the battery then down to a clip on the radiator. This didn't seem to have any breaks in the line. However, this system caused a "evap leak" code to latch three years ago. Not sure why it stopped last year.


My car only recently escaped a life of southern California. The lack of salt may explain why I still have the original on the car.


If you have an ODB code reader and need to identify the function of something with vac lines going to it, Unplug it and turn the ignition on. The engine computer will most likely throw a fault code and tell you what it does. Course you will have a fault latched and will need to clear it.


I'm trying to get up the courage to start driving with the EVAP solenoid and the Air Control 2 Valve disconnected to see if this changes anything.

Will let you know.