hi i bought a 94 dodge cummins 3500 with the computer(pcm control) fryed in it. they some sort of by passed it to be able to charge the batteries and run some stuff. now my questian is how much is a new computer and whats all the stuff which it controlls? i got a standard tranny in it so no worries about that. also my fuel gauge is messed up? thanks for all the info.

 

They must have added an external voltage regulator to the alternator. Other than than with a standard, the ECM doesn't do much other than cycle the grid heaters and run the dash gauges.

The fuel gauge being messed could be PCM related or the level sensor in the tank. They are known for getting worn or getting a loose rivot to make it not operate properly.

 

exactly they added an external voltage regulator. is the grid heater the heating system? can i put any pcm in their since its a standard? (used? how much is one?) is the fuel gauge controlled by the pcm? thanks

 

I doubt the PCm is fried. Its probably a bad ESS sensor. It will give you the same symptoms as a bad PCm such as no charging or A/c and such. Search crank sensors you will learn how to check it.

https://www.dieseltruckresource.com/...t=crank+sensor