Cummins ISX CM871 Technical discussion

If all you do is clean or replace the aftertreatment injector, then NO, there is nothing that HAS to be done in the ECM, but I Highly recommend that you (or at least someone) connects to the ECM with cummins Insite and performs a 'forced regen' while watching the temperature sensors. The DOC Inlet temp sensor should stay somehwere around 550-650, and the DPF Inlet temp sensor should climb after a bit (when the After-treatment injector becomes active) upwards of 1000-1100, and should do so within a minute or 2, once the injection starts,...Then the DPF Outlet temp. sensor should slowly climb after that to somewhere around 800-1000. The final kPa reading should be less than 3.0, and if all is really good, then it will be less than 2.0.

If your getting exhaust backpressure alarms then replace the exhaust backpressure sensor. They only usually last 500-600k miles anyway. At 780k miles, if ALL the sensors haven't been replaced by now, then its time to start doing so. There is no need to start chasing ghost problems because of old, weak or failing sensors.

If you had a coolant leak from the EGR cooler, then ALL your piping needs to be taken off and clened out like I show in that video, but since you have 780k miles on the truck, and while your at it, your best bet is to also take off the EGR valve itself and clean it out good or replace it. That many miles, if it isn't 'sticky' yet, then it soon will be, and you will be chasing problems even more. Take it off, clean it up, and inspect it for smooth plunger travel. Also look for rust and corrosion in and on its top. Road spray intrusion is common inside the top of them over time between the top and the bottom of the electric actuator part of it. The actuator comes right off with the 4 tall screws holding it and is easily replaced.

 

I am in pomona,CA today and tonight. I PM'd you my phone number. No need for steak dinner, I help others for free.

 

The IMAP sensor does not like carb and choke cleaner. Basicly, If its plastic, Don't soak it down with the stuff, but If its all metal, then no harm to it. The stuff works great on those pipes and such, especially if the soot will not come out dry. You might want to pick up a small can of red spray-paint that matches the motor color from wal-mart or something for after the Tune-up If you have to use a lot of the choke cleaner. Sometimes it will wash some of the paint off if you have to use a ton of it. I always touch my motor up a bit with a light dusting of red spray-paint when I am done. Makes for a cleaner-looking motor.

Just some thoughts on it,...Rawze