No Codes! No Lights!

‘15 Peterbilt 579 with newly installed low mileage 180k ISX15 CM 2350. Truck is in an almost constant “halfway”(for lack of a better term) regen. It does it’s active regen every 9 to 11 hours on the regen history but this “halfway” is going on for 5 to 7 hours between those. While in active the idle fuel is 3 to 3.5 GPH, the hot exhaust is on, idle is at 750 and I can disable it with the switch. This “halfway” the idle fuel is 2 to 2.2 GPH, No hot exhaust light, throttle responds like it’s in regen, idle at 750 and cannot disable it with the switch but can stop it with the cruise set button but if I tap the brake or clutch or rev it at all, it’s back on. Has anyone seen this before? Some background……The truck was also doing this with the old engine to a point as a company truck for a couple months but my write-ups were mostly ignored. The engine sank a liner and was parked for a year before I bought it and installed the new one. Most of the accessories except the turbo, EGR cooler and ECM are off the old engine with 677k. In the last few weeks it’s been to a dealer three times with one or two tier 2, then to Cummins. Both the dealer and I have replaced many things…..complete wiring harness from the DPF to the engine, DEF doser, DPF pressure sensor, two NOX sensors, turbo actuator, cleaned and flowed the DPF, removed and cleaned other sensors. The visit to Cummins produced a report that it failed the turbo speed test and I should “START WITH”$$$$$ installing a new turbo and DPF. Got a deal on a new DPF and installed it and went to the local dealer to reset the ECM yesterday. I have a hard time believing I need a new turbo with 180k on the engine and as many times as it’s been plugged in, nobody mentioned it. The dealer installed the new actuator and I’m SURE if that arm didn’t move properly THEY would have showed it to me to sell me a new turbo. With the new DPF I have not gone anywhere yet so there’s a slight chance it may be fixed but I doubt it. Anyone have any suggestions?

 

The new engine is a year newer with a different CPL but it came with numbers matching ECM and any particulars to the chassis were updated and also with the latest Cummins update. This issue was coming on with the old engine so it should be in the chassis or an accessory from the old engine. The new engine seller removed just about everything except the ECM, EGR cooler, turbo and actuator. In the last five weeks or so I’ve talked to countless techs including fleet mechanics and only one had seen this before and they fixed it with a new wiring harness, so I did that. I now realize this is a unique and rare problem and hoping someone else has seen it. Anything else I could have missed? Some obscure sensor somewhere? Thanks!

 

It is low mileage 185k, now, from a wreck. Old ESN 79740890 new ESN 79884745 both 2350s. The EGR assembly from the cooler, but not including the cooler, to, and including, the crossover pipe and everything on the left side of the engine except for the fuel pump and plumbing to the injectors, which pretty much had to stay with the new one, is from the old engine. The injectors, pump, turbo and actuator and ECM are original to the new engine. The dealer when connected to tier 2 did one or two little tweaks to the ECM that didn’t change my issue. Then whatever they tweaked was negated with the latest update at Cummins. I’m sure everything matches. Considering buying the EGR assembly, sensors and all, from the new engine if the price is right. He still has it but he’s on vacation ‘til next week.

 

Yes it does! The new engine and it’s ECM have never been separated. All numbers match, data plates….both ECM and with it’s downloaded data and engine data plate.