my 79 300d is not shuting down. I thought it was the vacume shut-off valve. i pulled it out and sucked on one side, air passes through. when i push on the pin it stops the air flow so i asume it is working. I tried blocking the vacume lines for the doors and what ever else come off of the three way spliter and manualy pushing the pin on the vacume switch ( i pulled the hoses into the engine compartment and re-attached the switch) but nothing happed. when I use the manual shut down, it really dose not want to die. what am i over looking?
thanks,

STRESSED

When you say you checked the shutoff valve it sounds like you checked the valve at the ignition switch. The shut off valve is mounted at the rear of the injector pump with one vacuum line attached to it. Remove the vacuum hose and attach a hand vacuum pump and see if it will shut off when you pump a vacuum. If not replace the vacuum shutoff valve.

I'm a little confused. The part # for the vacume switch on the ignition is the " vacume shut-off valve" at fastlane. are there two? second question is there is one vac. line (brown w/ blue) from the injector pump, it goes to the igintion vac. switch then comes to the first spliter (brown hose). my question is, the vac. switch at the ignition is open when the car is in the running position. how would pulling a vac. on the injector pump shut it down? does it not have a comstant vac. exept when shut off by the ignition switch?