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threert · 08-12-2016, **(Subject: cm870 excessive black smoke under power )**

need help with black smoke issue, turbo is about 4 yrs old, seems to check out fine,cac no leaks ,egr 2 months old ,cooler 1 1/2 yr old,exhaust pressure sensor new ,delta p sensor new ,air cleaner new ,i'm wondering if it could be turbo control valve is bad ,this happen about 4 yrs ago and i replaced turbo after the cummins shop said they couldn't fine anything wrong. anybody with any ideas? thanks also should actuator on turbo be extended all the way out during idle or retracted? imap sensor is 1 yr old

Rawze · 08-12-2016, **(Subject: cm870 excessive black smoke under power )**

Black smoke is usually either too much fuel or not enough air flow.

On a CM870, it is usually too little air flow. Since the turbo positioning is air operated, it could be an air pressure issue for the turbo circuit, the actuator, or the control module.

gearhead · 08-12-2016, **(Subject: cm870 excessive black smoke under power )**

Make sure if there is a filter on that control valve that it is clean. If it has filter it will be right around the turbo control valve.

threert · 08-12-2016, **(Subject: cm870 excessive black smoke under power )**

Thanks guys, I think its the egr that was just replaced a couple of months ago , unplugged it and about normal smoke, so I will replace it

Wiseman · 08-13-2016, **(Subject: cm870 excessive black smoke under power )**

(08-12-2016 )threert Wrote: Thanks guys, I think its the egr that was just replaced a couple of months ago , unplugged it and about normal smoke, so I will replace it

Get in touch with Gearhead or Unilevers before you do that .

Wiseman · 08-13-2016, **(Subject: cm870 excessive black smoke under power )**

(08-13-2016 )Bahdan Wrote: Mine did black smoke with brand new egr valve. Theres much more to it than just egr valve.

I would suggest doing the rawze egr tune up. Or just leave it unplugged.

Leaving the EGR unplugged is ok to just get home and take care of the problem!
Otherwise is not good to drive like that for many reasons. One of which is this will derate the engine and throw havoc in the ECM. Not to mention the CEL light and unstable EGT's .
In my book this is no no .
I still strongly suggest to get in touch with the guys mentioned above!
The choice is yours.

Rawze · 08-13-2016, **(Subject: cm870 excessive black smoke under power )**

I agree with not simply unplugging EGR valve. If you had a pyro gauge on the manifold, you will discover the turbo is getting to 900+ degrees easily and it shortens its lifespan to about half of what it should be.

preacherboy24 · 08-13-2016, **(Subject: cm870 excessive black smoke under power )**

(08-13-2016 )Rawze Wrote: I agree with not simply unplugging EGR valve. If you had a pyro gauge on the manifold, you will discover the turbo is getting to 900+ degrees easily and it shortens its lifespan to about half of what it should be.

On my 870 it put my engine into a silent derate. High boost all the time and LOW power.

Runt · 08-17-2016, **(Subject: cm870 excessive black smoke under power )**

Probably the Turbo Actuator. Some refer to it as the waste gate.
I have to replace mine almost once a year.
As soon as I see excessive black smoke and loss of power......I spend the $300.00 or so and replace it myself in about 20 minutes. Bingo, she's good for another length of time!

Runt