379 Wong shut off!!

What engine - could be a shut down solenoid on a Cat of that era?

 

My old Cat won't shut down by the key unless I have sufficient air pressure built up, otherwise I have to pull the fuel shutoff lever. Maybe Cummins had something similar?

 

Check the charging system..... If you are getting a feed to the alternator after turning the key off it will most likely keep the wire on your pump solenoid hot. Ran into this a lot on the old antique tractors I have worked on, especially when someone does a 6 volt to 12 volt conversion, a simple diode would solve the problem. Good luck.

 

Same with my 8V92TA in my Transtar, need 40 psi for the no fuel cylinder to pull it to no fuel position.

 

Same thing with my 3406 a model. Just keep a handy vice grips handy. Check for broken wire on fuel shut down. Or run a test hot wire see if it works.

 

What motor is in the truck

 

if I remember those old ntc's have a electric shut off on the back of pump. see if a wire has fell off or the shutoff has gone bad.