Can you equate a failed turbo actuator to the DPF system?
Based on only my understanding of this engine…2010 cummins with ISX motor…
If your Turbo Actuator is bad then it can effect charge pressure. If charge pressure is too low, the the engine will have reduced power and create excess soot. It has to be pretty bad tho, for it to clog up the DPF. Bad enough to notice it fairly easily. Most often, it is accompanied with actuator alarms as well. Also, incorrect charge pressure during a passive REGEN, if the ECM detects this, will fail the Regen cycle, disabling Regen’s, and setting the all too familiar ‘DOC Face Plug Alarm’. That is not the only cause of that alarm, the engine likes to throw that alarm for several reasons. I call it the ‘Money Maker’ alarm, because it is way too sensitive, and make shops lots of money. The question posed here, is how does one know for sure, a Turbo actuator is bad to begin with?…
If your Actuator itself is bad, then it will usually give an alarm, but positioning alarms can be a false alarm caused by a bad VG ring in the turbo itself. The only way to know if the alarms are from the actuator itself, is to remove it and do a good turbo inspection first. As well, if there is more than 1/4 – 1/2 tooth free-play in the drive gear, then its time to replace the actuator, and can be the cause in itself. Actuator alarms can also come from improper installation. Many mechanics are lazy and get away with just throwing one on semi-blindly, and get away with it, because the full working range of the actuator/VG ring is hardly used during engine operation. I found out this when working with people who do EGR deletes, and remap their turbo for maximum efficiency. Doing this reveals quickly, if a Turbo Calibration has not been done properly, or if the VG arm position was not set properly during installation, because suddenly, you get actuator alarms. After looking into this deeper, I found that if the actuator is not installed exactly right, then many times, no, you will not get alarms, but in fact, you loose a bit of combustion efficiency, effecting fuel mileage a bit. Again, NOT a good practice to assume it will be right after simply ‘Slapping One On’, then doing just that final calibration alone, using Insite software.
But wait,…there’s more,…(complicating things further),…Actuator failures and positioning alarms can indeed be caused by a couple of outside sources as well,…A bad IMAP (Intake Manifold Pressure Sensor), and/or a bad Exhaust back-pressure sensor can in fact cause turbo Actuator alarms. The sad thing about this, is that one of these sensors reading incorrectly, but not failed yet, will almost always cause turbo/actuator alarms, EGR, or other alarms, long before the engine will throw a single code for one of these sensors. Replacing the Actuator, when this is happening, will sometimes clear your problem up a bit, because of less backlash in the gears, but then you get problems somewhere else in the engine. The only way to ensure your not chasing a ghost, is to ensure your IMAP, and exhaust BP sensors are in very good condition before resorting to accusing the actuator/turbo to begin with.
But Wait,….there’s more still yet,…DPF problems can be caused by the fact that the intake manifold and/or venturi, Delta-P, etc. (everything related to an EGR Tune-up), and A worn, or out of calibration Actuator, but not actually bad yet, can give alarms because of the erratic demands by the ECM. Replacing it there again, will clear one problem short term, but not solve the problems of the engine.
Confused yet?,…This is exactly why many shop do not do a good job solving this, so the Answer to a problem like this is simply to ‘Cover All The Bases’ progressively, Starting with a thorough EGR Tune-up, Verification that the engine is running well and not producing excess soot, A thorough turbo and actuator inspection / replacement if necessary, A new After-treatment injector so that a force regen can be performed to fix the DPF, and so that anomalies can be watched for during the regen, with a verified kPa of less than 2.0.
Just my opinion on the question you asked, and would also be what I would do to my own truck, if faced with such errors. I am not out here to play, I am out here to make money, and to move freight. I will not compromise my operation, trying to guess at my problems, because it is just too costly. It is far cheaper to cover all things related to a problem, then afterwords, to take the time to go through the rest of the truck with a fine tooth comb, fixing anything even remotely suspect, than it is to be down again, or become unreliable. That is one of the main reasons that I am always testing, inspecting, looking under, and around things, and do very thorough maintenance to my truck. I want to know BEFORE something fails, so that I can plan for it. It has not steered me wrong yet.
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