Yeah some have ECM issues, well as for gremlins on our M series, I Am not a big Fan of the Huie pump engines, ex, C7 Acert engines, we have replaced the pump 3 times now at 5 grand a pop, plus Cat has to clean the head so your looking at 9 grand per pump, so common rail are better, we are on our third engine in our 140M and so are the other older 140Ms at our sister shops and a 12M 2 lost a engine also, our last engine From Cat was a new reman and burns about 14liters of oil on a 12hr shift, was burning oil right from day one which Cat said was normal, but has got worst now, wiring harnesses on the Ms are a working part also so if you get a broken wire good luck finding it, the harness is about 6" round and we had to replace it, not cheap, I could go on and on, I have a older thread called 140M down, you may find it interesting, Find a H series, they are out there, all depends on what you want to pay, best of luck to you