Thanks in advance for any suggestions and help. I recently performed an In-Frame overhaul to an '09 Maxxforce DT285 in a International Durastar due to low compression. During the overhaul the cylinder head was completely rebuilt by a reputable machine shop and both EGR coolers were pressure tested for leaks before reinstallation. After the overhaul was complete we were getting active faults for the Intake Throttle Valve during road tests. We were also getting faults for Unable to Build Exhaust Back Pressure during the KOER Standard Test and Overduty Cycle during the Air Management test. After replacing the Intake Throttle Valve that fault has not returned. The variable turbo was found to be sticking and it was replaced after finding two cracks in the turbine housing when we disassembled it to clean the vanes and unison ring. After the new turbo was installed we are now getting fault 3347 (Under Duty Cycle) during the Air Management test when the engine is hot. However, if we perform the AMT when the engine just reaches operating temp we get faults 2352 (EBP Above Desired) and 3346 (EBP unable to build during EGR test). These two faults go away during the AMT once the engine is hot and fault 3347 is the only one that returns. A new engine sensor wire harness was installed due to some wire chafing that was found and the EGR valve has also been replaced. Our KOEO sensor readings are as follows: Baro 14.4 psi, Boost .29 psi, EBP .01 psi. Under load while driving we have 35 psi of EBP and 26 psi of boost. There are no exhaust or intake leaks we can find and all pressure sensors have been checked as per the VIN. The DPF has been separated and visual checked for any face plugging. After performing the fault tree diagnostics we were directed to replace the turbo actuator, even though it was already new we tried a different one but the fault still returns. I don't feel comfortable letting the vehicle go after an overhaul when it isn't passing an air management test. Does anyone have any suggestions on what we are missing? I can't believe there is something wrong mechanically with the new turbo that was installed as the movement feels as it should, even with the actuator off.
We removed and visually inspected the DPF and its looked ok. Also, the differential pressures are within spec. We haven't checked the DOC but don't think we can because it's part of the turbo outlet pipe.
'09 Maxxforce DT DTC 3347 Air Management Test
Posted - 10/29/2015 : 6:15:34 PM
