Hello to you all, I am new to mercedesWorld, thank you for having me on board.
I have a 4cyl Sprinter, 2000 model, which was running perfectly fine, and i managed to snap an injecter securing bolt upon replacing the injector copper washer to stop compression blow by.
I decided to disconnect the battery, and proceed to use a welding method to extract the broken bolt, which came out on the 16th attempt. After removing the injector, replacing it, bleeding the fuel through both pumps and all hoses, i tried starting it, and had no luck, so i then tried pressurising the fuel tank with compressed air and tried helping the high pressure pump to recieve fuel, and that didn't wiork either. i then decided to use "start ya basterd" which got it running, although would shut down completely after about 10 seconds of "start ya bastard". At this point i assumed the worst as it being my car that i'm working on and decided to surrender it to mercedes benz vans "Grand motors" and the dealer advised me that the ecu was not getting power due to the dme relay not activating from a loss of earth which is internally induced by the ecu. so they simply induced an earth and managed to get power to the ecu, and obviously threw heaps of codes relating to no high fuel pressure, vehicle only developing 17 bar as opposed to the min 320 bar to make the injectors start to work. They told me that they suspected that the welding had caused electronic problems and that the suggest i replace the ecu, and wps or immobiliser, so i took the ecu, immobiliser, key and key reader to an EFI specialist who bench tested the ecu, to which it showed nothing to be wrong with it, so the decision to replace the ecu has made me hesitant, and i'm thinking of a better option.
Since this has all happened, i've replaced the fuel press. reg. "o" rings, externally supplied pressured fuel to the high pressure pump, done every single possible thing to bleed air from the high pressure curcuit, bypassed the fuel lock solonoid, checked all the fuses, and found a few at the battery area that wern't blown but were not allowing current through due to bad contacts, which seemed to feed power to the ecu, replaced fuel filter, i can tell that the ecu is doing something as some of the solonoids can be heard that are driven from ecu. cracked all injector hoses while cranking, and now at this point where i'm hoping to find a donor vehicle where i can put my suspected faulty ecu and wsp into to see if it would stop a known good vehicle from running, and then obviously take appropriate action. In this way non of the electronics can be affected, and it will illiminate the diagnosis. So if there is anyone out there with either some advise, or perhaps a donor vehicle who's chasing a couple hundred bucks to let me diagnose for an hour, Please keep me in mind. All i can say is that it's been verrrrrrrry frustrating.
Thanks guys, and very sorry about the long essay