CM870 Smoking Issues

[Submariner]

So a quick update as the saga continues with this engine.... It started dumping smoke badly at idle again today. I pulled over to a parking lot, disconnected the air hose to the turbo. The actuator moved smoothly through the full range and the smoking increased in the “big turbo” position. On a whim, I disconnected the intake air temp sensor on the manifold, engine fan kicked on immediately and with in seconds the smoke cleared and ran perfect. Installed another new temp sensor, fan disengaged and immediately started pouring smoke out the stacks. Unhooked the sensor, fan came back on and smoke cleared, idled perfectly. According to KW, the new ECM has the latest Cummins software version and is correct for the CPL. Do these engines when they loose a input like intake air temp, default to a “safe” fuel map?

[Rawze]

the engine has multiple operating modes.. it is very possible it is changing into a different run mode when you unplug that sensor... you need Insite to properly troubleshoot your problem, and you need ( C A L T E R M ) if you want to know what engine modes it is jumping into or out of, what it is actually doing, etc. ... All your accomplishing by unplugging stuff randomly is nothing but guessing blindly at it.


smoking issues are typically not rocket science... clean up the egr and intake systems/circuits on it,.. replace all the old sensors that are more than a couple years old, including the Delta-P and crossover tubes for it,. Check the EGR valve, etc. and go from there.

BTW: The EGR valve on the CM870 is notorious for going bad.. it is a bad design where it suffers the heat from the exhaust, and they like to go bad repeatedly. The Delta-P sensor is located (roughly) behind/to the right of the fuel filter and is one of the most neglected circuits and sensors on the 870.


If you can't figure it out, then take a trip down to Mr.hags in atlanta and get some professional help by someone who has this stuff, etc.

[DarrenEW]

I am having a white smoking issue with my cummins cm870 as well. It was rebuilt and has new injectors, so I am assuming that it's not one of them. When I give it the beans, as in accelerating a couple times, it stops smoking white at low idle. It also doesn't run very smoothly at start up. Is it possible that something needs to be reprogrammed in the ecm after the rebuild?

[Lonestar10]

just cause its got new stuff done mean nutting can be installed wrong, also cummins reman parts are becoming crap quality.

[Rawze]

(02-21-2020 )Lonestar10 Wrote:  ... also cummins reman parts are becoming crap quality.

I have helped hundreds of people with all sorts of reman certified OE parts. Everything from reman turbochargers, reman injectors, reman air compressors, etc. ... It has been rare to see any of them what could be considered simply "crap" though.

This however also does not mean that a person should rely blindly on something, especially if it has had a failure in its past (and now is a reman part) either. - A person should always do their homework before choosing a reman part vs. an alternative vs. brand new OE parts.


- I HOWEVER STRONGLY DISAGREE with this new bulls$it policy they are forcing onto truck owners (illegally) of having to take your truck to an OE certified collection of complete morons before you can make a warranty claim on a part you have purchased though ..-- THAT IS UTTER BULLS#$IT in my book, no matter how a person looks at it. They are not alone though in this horse#crap policy either. There are many other companies that do this same thing.

[Lonestar10]

i was basing this off getting 2 injectors out of 6 that were bad out of the boxes failing the bubble test, 1 timing and 1 fueling actuator bad out of the box timing leaked fuel and metering wasnt delivering the fuel it was suppose to, 1 actuator of 4 we put on dads 870 the connector was screwed up and wouldnt stay connected. 2 ECMs bad right out of the box

then add on of the factor that 8 months after replacement still waiting on a yes or no on warranty claims.