Re: Old and stupid
Yes,most starters will turn the same direction even if the battery is hooked up backwards..some with permanent magnets might spin backwards,but I think the starter drive has a one way clutch that will not engage if it spun backwards even if it has a solenoid to shove the gear into the flywheel ring gear..
As suggested,the reversed polarity may have fried something else--on a diesel there is usually a fuel shut off solenoid unless there is a manual shut off lever on the injector pump..that solenoid cuts off the fuel flow when you turn the key off..if that fails to open with the key on,no fuel will get to the injector pump and it'll just crank over and not start..it may have run temporarily on some fuel still left in the lines and injectors..
Most of the other electrical items on a diesel dont really keep it from running if they fail--the alternator wont affect if it runs or not if it got fried,the battery will just die eventually from it not being recharged..the fuel shutoff solenoid wont open if the battery gets very close to dead to though don't forget..
I'm not a diesel expert but I've been forced to learn basics due to owning two trucks with them..