Hello, I am working on a 1999 IH 4700 with a T444E engine. The truck would not start, had a code for no CMP signal, replaced CMP sensor, still no start. I began going thru all wiring and testing for power, ground, and 5v references. Pulled the drivers valve cover off to test injector wiring. I unplugged 1 injector at a time and tried to start engine. When I got to third injector back (#6?) the truck fired right up and ran fine on 7 cylinders. Tested wiring to that injector and it did not have a ground with key ON like the other injectors. I then ohm'd the wiring from the PCM to the injector harness and all checked out good, cut open the harness a few inches back and wires look fine. At this point I believe the IDM is bad, and it is inside the ECM so I would need to replace the ECM. Does this sound reasonable to anyone? I know these use the same ECM as the DT466 but I assume I would have to get it programmed to run 8 cylinders instead of 6. If I find an ECM with the same part number, can I take it to the dealer for programming, or do I have to take the entire truck? Really trying to avoid that. Thanks for any help/opinions!
The dealers can program the ecm by itself as long as they still have the connections for that particular ecm. You would have to call them and ask.
Good to know, I will call them in the morning. What do you think about my diagnosis? Have any experience with the t444/7.3 engines?
It should configure itself when the ecu boots up. Same as the Ford gas engines that use the same ecu on V6 and V8 engines. It counts injectors when it verifies them at boot up and sets itself up to run the appropriate number of them. Never tried it with Navistar stuff but a V6 to V8 swap on Mustangs and Rangers I’ve done you just plug in whatever engine is in there and it runs it. Chev 4.3 management will run a 305 too. Again, it runs whatever one you have plugged in at the time. As you’ve already verified your wiring I think I’d be leaning toward a problem inside the magic box too.
Get or find someone with ServiceMaxx J1708 + link diagnostic (I think you can still download the software from Navistar for free). Find out what's going on before you drive it through the parts store guessing. IH/Navistar T444e and Ford 7.3L electronics are not the same.
Easier said than done. If I had access to that equipment I would have used it already. Im trying to make the best educated guess through diagnosing the issue without a scanner. Definitely not ideal
The valve cover gaskets with the injector plugs in them would short out and cause problems with those engines, cheapest way to go if you don't want to scan it
I removed the gasket and ohm'd every wire. They all ohm'd out the same. Also, from the injector harness to the ECM, I still get a different reading on the injector 6 wire
