hey guys, as some may know im doing a 95' 12v engine swap into my 90' truck, so i talked to a mechanic and he told me that i just had to wire up the red wire from the fuel shutoff solenoid to power( so im using my old fuel solenoid power wire, from my 1st gen motor as the power wire to the new fuel shutoff solenoid) and the black wire is ground, so thats what i did and i noticed on a test run that the solenoid got SUPER hot so i unhooked the power wire. so my question is why are there three wires to the fuel shutoff solenoid. and why would the solenoid start burning up. is it not suppose to have 12 volts to it?? thanks

jason

 

come on peoples, doesn't anyone know how these thing work??? please just a little help

 

The solenoid consists of two coils, one that lifts it up and one that holds it.

One wire is for the solenoid lift up coil, it draws a lot of juice and will overheat and fry the solenoid. Might have already happened. This wire is only energized when cranking though a relay that is triggered by the starter motor. Other wire is for the hold up coil, energized when the key is in the run position. Last wire is a ground.
All this explained in detail with a wiring diagram here http://www.fostertruck.com/dodge/default.htm

 

There are two inputs to the fuel cutoff solenoid on my 97. They each feed separate coils. One is a low current coil (4 amps?) that runs off the ignition. The coil holds the fuel cutoff shaft up when the truck is running. The other coil runs off a relay that provides power straight from the battery. The coil pulls the solenoid shaft up and draws something like 40+amps. It is only in drawing current when cranking the engine. Attached is a diagram I drew a while back from information extracted from the 97 service manual.

 

thanks alot, i will probably wire a switch system to it to make it work. in makeing this switch thing work, what fuses should i use for the red wire(this one pulls the solenoid up) and the white wire(which holds the solenoid up while driving) thanks again for your help.

jason

 

Stock the hold up coil fuse is 10 amp, the lift coil is protected by a blue fusible link (360°F at any autoparts) connected directly to the battery and switched by a relay.

You might want to consider abandoning the shut down solenoid system and replacing the shutdown with a choke type pull cable. This is especially true since the solenoid was overheated, it might not have much life left.

 

just take off the solinoid, hook a spring on the arm off the pump, so it pulls it in the on position, and throw a pull cable/choke cable on it, you pull it, it kills the truck and the spring pulls the cable and the arm both back to the on position, so next time you start the truck its already on.... I just did my 98,{solinoid was burnt up} did mine with an actual throttle cable off of a parts CTD 2wd, I can pull the cable with 2 fingers, works slick!!!!