Detroits 12.7 shuts down and wont refire
 

can you refer me to anyone whos familiar wiht 12.7 detroit. i bought a 93 peterbilt 379 and later found out that the truck shuts down in the rain and will not restart.the major overhaul done at Detroit has 91,000 miles on ti out of warranty for time tho. the motor did the same thing before rebiulding it... it has to be a ground or somethign wiring related. i was told soem mice were found under hood of truck but nothing looks chewed up... any advice as to what would cause this motor to just shut down only when moisture present or where i can begin to search for issues.or how to troubleshoot it?any info would be super to start with or maybe you possibly know of someone who specializes in detroits? thanks Rich Foreman indiana trucker.the garages seem to get it running again somehow but unable to cure the issue because it reoccurs mostly when it rains and not always. the previous owner thinks mice got intot he wiring somewhere but unsure no visual evidence of mice or rodents anywhere under hood on under dash? any suggestions or ever heard of this happening??

I merged the replies with your post in the help section, but in this particular case I will also leave it in here just to be sure all the right members see it. When it is resolved we can put it back together and leave it her for future referance. Good Luck.

I used to work in a truck shop and we had a 98 pete with a 12.7 come in and it was doing about the same. We found that it was in the harness behind the starter that runs along the back of the motor. If the starter has been replace it may not be behind it any more. But what had happened is that where it makes a bend 3 wires were broken just enough to let moisture in them and it would not die. I forget where the wires run to but once it dried out it would start back up. Another thing to do is check the plug in in that go to ecm I have seen them get corroded and do some weird things. If you have any more questions just contact me. I have worked on these motors for a long time and know quite a bit about them. I don,t know where in Indiana your from but I am around Vincennes.

Ive also seen a series 60 do kinda the same thing. It was the water level sensor in the radiator.