I am investigating my 1984 300SD's shutoff time. At one time, the engine was taking 12 seconds to stop with the key. In 12 seconds, I could already be in the house if I hurried. Something had to be done. I decided to follow the directions for replacing the shutoff valve at Dieselgaint. The directions are great. The link is:
http://www.dieselgiant.com/repairyourshutoffvalve.htm
I ended up buying two vacuum shutoff valves at the JY for $9. Instead of taking the shutoff valve off of my car, I decided to test the used ones directly on the vacuum line coming off of the vacuum pump. The arms of both of the shutoff valves take 7 seconds to fully retract. I added two small vacuum reservoirs to the shutoff valve lines. I managed to get the engine to shut off in 7 seconds.
This is what I think is happening in the 7 seconds. For the 5 seconds, it seems the engines idles normally, but in the 6th second, the engine begins to slow down. In the last second, the engine shakes and dies like it is starving to death.
Is the 7 second shut off time normal? The engine will shutdown instantly as quickly as I push the stop lever. I am suspecting that there is not enough vacuum being produced by the pump. However, the car's brakes work great. The HVAC doors open and close as they should. The transmission shifts nicely. The vacuum system will even hold vacuum overnight. Any ideas?
06-26-2011, 01:28 PM
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