I drive a 2003 Jetta Wagon TDI. To my knowledge it is completely stock. I love the car and have always been concerned about the consequences of a runaway since I care for the car very well and I intend on keeping the car for an extended period of time.
I read every post that I see regarding runaways and how to stop them. Through this reading I had come to the disappointing conclusion that VW engineers had dropped the ball and not set things up properly to shut the engine down in event of a runaway even though everything (anti-shudder valve) was in place to do so. I eventually set out to confirm this by watching the anti-shudder valve as the engine was shut down. It appeared that my fears were confirmed as the valve only closed for 2 seconds or less which would not be sufficient to shut down a full blown runaway in my opinion.
I began devising a plan to have the anti-shudder valve stay closed longer upon shutting the key off to solve this. I was pretty much ready to start acquiring the parts to do it when I ran across this post. http://forums.tdiclub.com/showthread.php?t=276398 Posts #11 and #12 by Ski in NC were the ones that really peaked my interest. Could it be possible that the VW engineers had not dropped the ball?
Well the weather was reasonably warm today and I had some time so I set out to see if I could duplicate Ski in NC's findings. I back probed the N239 (anti-shudder valve control solenoid) electrical connector and lead wires into the cabin which I connected to my volt meter to. I started the engine and my meter read 24 mv which is negligible. I headed out of town a couple miles to a nice steep hill and as I crested the hill I shut down the engine and left it coast in gear to keep the engine turning with the key off. The volt meter went to 13.58 volts showing that the anti-shudder valve was actuated. The meter stayed at 13.58 volts for well over a mile as the car slowed down. Eventually when the car was going slow enough that it was just about to stop I pushed in the clutch and the engine stopped turning. within about a second the meter went to 0 volts. I figure the valve was actuated for about 1.5 min. Certainly long enough to stop a runaway! I tried it a second time with the same result.
From this I conclude that if a person maintains the anti-shudder valve system and keeps it in good working order that it will indeed shut down a runaway and help prevent engine/bodily damage. Anyone who has had a runaway that they were unable to shut down with the key also had a problem with their anti-shudder valve. Joester in post #16 of this thread http://forums.tdiclub.com/showthread.php?t=273249 is completely wrong provided the anti-shudder valve a ECU are operating correctly.
I read every post that I see regarding runaways and how to stop them. Through this reading I had come to the disappointing conclusion that VW engineers had dropped the ball and not set things up properly to shut the engine down in event of a runaway even though everything (anti-shudder valve) was in place to do so. I eventually set out to confirm this by watching the anti-shudder valve as the engine was shut down. It appeared that my fears were confirmed as the valve only closed for 2 seconds or less which would not be sufficient to shut down a full blown runaway in my opinion.
I began devising a plan to have the anti-shudder valve stay closed longer upon shutting the key off to solve this. I was pretty much ready to start acquiring the parts to do it when I ran across this post. http://forums.tdiclub.com/showthread.php?t=276398 Posts #11 and #12 by Ski in NC were the ones that really peaked my interest. Could it be possible that the VW engineers had not dropped the ball?
Well the weather was reasonably warm today and I had some time so I set out to see if I could duplicate Ski in NC's findings. I back probed the N239 (anti-shudder valve control solenoid) electrical connector and lead wires into the cabin which I connected to my volt meter to. I started the engine and my meter read 24 mv which is negligible. I headed out of town a couple miles to a nice steep hill and as I crested the hill I shut down the engine and left it coast in gear to keep the engine turning with the key off. The volt meter went to 13.58 volts showing that the anti-shudder valve was actuated. The meter stayed at 13.58 volts for well over a mile as the car slowed down. Eventually when the car was going slow enough that it was just about to stop I pushed in the clutch and the engine stopped turning. within about a second the meter went to 0 volts. I figure the valve was actuated for about 1.5 min. Certainly long enough to stop a runaway! I tried it a second time with the same result.
From this I conclude that if a person maintains the anti-shudder valve system and keeps it in good working order that it will indeed shut down a runaway and help prevent engine/bodily damage. Anyone who has had a runaway that they were unable to shut down with the key also had a problem with their anti-shudder valve. Joester in post #16 of this thread http://forums.tdiclub.com/showthread.php?t=273249 is completely wrong provided the anti-shudder valve a ECU are operating correctly.