Mack MP7 Derate and redish oil

[B_harward]

Sorry this is a long read. We’ve  been intermittently battling this truck for about a year. It is a 2013 Mack MRU concrete pump truck, with an MP7. Started out with code SPN4094 FMI 1 (insufficient regen quality) and a mild derate. Ran forced regen as first step in trouble shooting, problem solved for a month or so. Same code came back as FMI 1 and 18(moderately severe) as well as SPN5246 FMI 0(SCR inducement severity) which is signifying it is in the 5mph derate. Through fault tracing with tech tool, we found and resolved the issues it revealed. New DEF Dosing Valve due to worn nozzle overdosing, new OEM NOx sensors, new EGR pressure differential sensor and Venturi pipe, serviced the fuel nozzle, spark plugs, wires, and coil in the bottom of the DPF. Verified the DEF pump can build and maintain pressure and is dosing correctly. At this point, going through tech tools fault tracing and every possible test you can run on tech tool, it says there is no issue found. The engine runs great until it throws the codes and is in derate. So we have the DPF professionally cleaned. All of this was over the course of 6 months. At this point we have outsourced to another mechanic we are friendly with that worked for Mack for 15 years. He came to the same conclusion as we did and got one of his buddies involved in Mack’s research and reliability department. After explaining our findings he said it has to be either the DPF, SCR, or an upstream issue(Engine issue) so we bought a new DPF, and had the SCR cleaned and tested. At this point we noticed the oil has a red tint to it. So now we’re down to upstream issue. We’ve used a combustion leak tester on the coolant reservoir, didn’t show anything, the EGR cooler is fine, we’ve even pulled the injectors, and pressurized the coolant reservoir with a block heater plugged in to check for cracked head. As far as we can tell, no issue there. Anybody ever dealt with something similar?

[fjh]

3 hours ago, B_harward said:

Sorry this is a long read. We’ve  been intermittently battling this truck for about a year. It is a 2013 Mack MRU concrete pump truck, with an MP7. Started out with code SPN4094 FMI 1 (insufficient regen quality) and a mild derate. Ran forced regen as first step in trouble shooting, problem solved for a month or so. Same code came back as FMI 1 and 18(moderately severe) as well as SPN5246 FMI 0(SCR inducement severity) which is signifying it is in the 5mph derate. Through fault tracing with tech tool, we found and resolved the issues it revealed. New DEF Dosing Valve due to worn nozzle overdosing, new OEM NOx sensors, new EGR pressure differential sensor and Venturi pipe, serviced the fuel nozzle, spark plugs, wires, and coil in the bottom of the DPF. Verified the DEF pump can build and maintain pressure and is dosing correctly. At this point, going through tech tools fault tracing and every possible test you can run on tech tool, it says there is no issue found. The engine runs great until it throws the codes and is in derate. So we have the DPF professionally cleaned. All of this was over the course of 6 months. At this point we have outsourced to another mechanic we are friendly with that worked for Mack for 15 years. He came to the same conclusion as we did and got one of his buddies involved in Mack’s research and reliability department. After explaining our findings he said it has to be either the DPF, SCR, or an upstream issue(Engine issue) so we bought a new DPF, and had the SCR cleaned and tested. At this point we noticed the oil has a red tint to it. So now we’re down to upstream issue. We’ve used a combustion leak tester on the coolant reservoir, didn’t show anything, the EGR cooler is fine, we’ve even pulled the injectors, and pressurized the coolant reservoir with a block heater plugged in to check for cracked head. As far as we can tell, no issue there. Anybody ever dealt with something similar?

Have you done an oil sample?