so i was reading this (because i heard that ac noise is bad for ecms) and i was wondering if it would hurt my replacement ecm to crank my truck to check my VAC, and how much diesel i would need to run it to do that, because my fuel sending sending situation is FU*KERD and i don't know when i can get the right parts in, but i can pull fuel out of a jug, just don't want to fight to get a 5 gal bucket, when all i need is a gal. ( also i 

AC voltage doesn't immediately kill it.  so you could wait.

 

Or take the alternator to have it checked.  Rebuild shops don't normally check for AC but ask them to do it.

 

If you return the fuel to the jug you can run a long time on a couple gallons.  If you run from the jug but return to the tank it will disappear quickly.  I drove less than 3 miles on 5 gallons on a jug as supply, but return still connected to tank. (the return flow is significant)

 

GL  HTH

 

Hag