2009 ISX435 ST Emission Issues

We have seen where the egr valve is not fully closing, but also not logging a fault for being out of position and the engine ends up loosing boost pressure out the exhaust. This would explain the pressure codes. The 2973 code also directs you to trouble shoot the 2345 first. The ECM is detecting turbo speed changes that are physically impossible. Most results of 2345 trouble shooting points to a turbo speed sensor or wiring problem. During this time the ECM basically ignores the measured turbo speed and "guesses". The ECM will command the actuator based on default values which may be insufficient and also causing the low manifold pressures. During a regen the ECM will command the turbo actuator to close to at least 89%. This will cause exhaust back pressure to increase load and exhaust heat. There are three temp sensors in the DOC/DPF. The first one is the DOC( catalyst ) inlet temp. This must be a minimum of 525 degrees,(ballpark) or the doser injector will never even fire. The next temp sensor is the DPF inlet temp, this must also be at least 525 degrees or the doser will never fire. The third sensor is the DPF outlet and is used for monitoring system temps during the active or forced regen, but not needed to start one. If the DOC and DPF inlet temps are 525 or better the injector should fire. This will raise the DOC inlet temps slightly, but the DPF temps should reach 1000+ degrees. The DPF outlet is usually with in 100 degrees or so of the DPF inlet temp. If your DOC inlet temp will not reach 525 the engine cannot maintain enough exhaust back pressure. The turbo is the usual culprit, as the actuator will not close as commanded, or the engine is reading exhaust back pressure wrong. Exhaust leaks could also cause this, but usually you can smell that. If the temps are hot enough at the DOC inlet and the injector is firing, but the DPF inlet will not reach 1000, ( usually less than 800), you could have a plugged or dirty, or malfunctioning doser injector, or the precious metal coating on the DOC is burnt off and the catalytic chemical reaction isn't taking place which causes the 1000+ degree heat. DOC could also be cracked or some other damage/plugging. If the injector is coming on, but low DPF inlet temp, and high DPF outlet temp of 1150 or more, (1220 degrees sets a code for temp too high) this means the DOC is not working and the catalyst reaction and temp increase is occurring in the DPF. The DPF is supposed to "bake" the soot into ash, not "burn" it. The DPF material is not designed for this and quickly gets damaged from the excessive heat, replacement is required. Do you happen to know what is happening with the temps? Having the DOC and DPF cleaned doesn't mean they will work properly. How are they being cleaned? What is the mileage of this unit?

 

this engine also has an open TRP T1141. an ecm recalibration to improve engine and aftertreatment durability.

 

That's only if he replaced the DPF, I saw that too.

 

At this point I would strongly recomend checking the static injection timing. It's a procedure that requires some special tooling that every cummins dealer would have. The injector camshaft can be "timed" to the crankshaft but be running retarded(late) or advanced. When the 07 emission engine came out, it wasn't long after they came out with a new series of camshaft wedges ie 4.25deg, 4.50deg, and 4.75 deg. as it was never an issue before because even an engine running late would maybe smoke a bit, but didn't have a DPF. I have checked several engines and found one so far that was right. After adjusting the timing on the engines I have done, I have gotten a lot of positive feed back from the drivers, including better fuel economy. If the fire in the cylinders isn't right your aftertreatment system is working harder to clean it up. If you get this done and an adjustment is required make sure they replace the camshaft retainer with the updated one and use a little loctite 609 as requested by cummins. I agree with post by Heavy D, egr valves not sealed and exhaust leaks is a big problem. If the egr valve isn't sealing you will get boost codes, and the engine will lack power/sluggish. Good luck hope this helps.

 

The ECM recalibration is a software update to change some of the regen parameters. I can't remember right now what gets changed. But this recalibration is only needed if you replaced your DPF with a different/reman or new DPF. The recal is actually a different ECM code all together, so it is a rather significant change. The newer DPFs have a slightly different material inside. If you use a new DPF with the old calibration you will damage the new DPF. I don't know if the new calibration is bad with an older DPF or not. Is the truck at an actual Cummins dealer? These engines have been around long enough now they should be able to fix the hell out of it! Basically I would have to tackle any active codes, make sure the ECM calibration is correct/up to date, then just do a forced regen and see what is going on.

 

Any details?