CM 870 Smoking white

[Ken Worth]

Hello guys my cm 870 started smoking white smoke and what feels like sputtering when reving up. But If I take off and start driving the smoke stops and truck is normal/ no power loss , or if I raise the ideal up to 1100-1200 and hold it there it will smoke for a little and then clear out to normal no smoke no sputtering nothing.

Any ideas what could be causing this? Thanks guys

So far I changed fuel filters.

[tree98]

Is it using coolant? Could be the head gasket..... dropped liner?.

[Rawze]

also do injector leak tests on it too..
ref: http://rawze.com/forums/showthread.php?t...8#pid67948

[Ken Worth]

(01-16-2025 )tree98 Wrote:  Is it using coolant? Could be the head gasket..... dropped liner?.

Not using coolant or anything. Uses some oil but it has front main leaking like most Cummins

[Ken Worth]

(01-16-2025 )Rawze Wrote:  also do injector leak tests on it too..
ref: http://rawze.com/forums/showthread.php?t...8#pid67948

Am still waiting on the adapter to do a leak test.

But I was Abel to get a cylinder cutout test and turning off number 4 it stops smoking. Turing of the front 3 causes to smoke even more. Or turning of back 3 it also stops. I was scared to try and run it on one at a time.


Could this indicate number 4 injector leaking?

Thanks for the reply’s guys.

[tree98]

Yea seems to be something going on with #4

You can run it on 1 cylinder, won't hurt it at all.

[Ken Worth]

(01-25-2025 )tree98 Wrote:  Yea seems to be something going on with #4

You can run it on 1 cylinder, won't hurt it at all.

Amazon finally delivered the adapter for the leak test and I jumped on it real quick.

When I mount it on the rear fueling actuator (back of the engine) there is 0 bubbles. But when I mount it on the front one it has crazy big bubbles.
Would This mean it’s one or all of the front 3 injectors right?
On the cm870 there is 4 actuators, the very first one is fueling for the front 3 and the very last 4th in line, is for the rear 3 right? Or have I miss read the instructions on test procedure.

I was not abel to bar it by hand to see if it between A B or C because my damper markings are missing/and it got dark out side. I will do that tomorrow after finding the correct markings on the damper.

[tree98]

(01-25-2025 )Ken Worth Wrote:  When I mount it on the rear fueling actuator (back of the engine) there is 0 bubbles. But when I mount it on the front one it has crazy big bubbles.
Would This mean it’s one or all of the front 3 injectors right?

Yes

(01-25-2025 )Ken Worth Wrote:  On the cm870 there is 4 actuators, the very first one is fueling for the front 3 and the very last 4th in line, is for the rear 3 right?

Yes.......

it's possible you have a bad timing or metering actuator for the back 3 since you've found an issue on #4 but no bubbles.

Also look VERY close when barring the engine over, "bubbles" can be easy to miss. Watch Rawze's video(3 short videos) and you'll see what i mean.

https://youtu.be/Wu_WN8BA-LA?si=atQphHcIJ6w-xbb6

[Ken Worth]

(01-26-2025 )tree98 Wrote:  

(01-25-2025 )Ken Worth Wrote:  When I mount it on the rear fueling actuator (back of the engine) there is 0 bubbles. But when I mount it on the front one it has crazy big bubbles.
Would This mean it’s one or all of the front 3 injectors right?

Yes

(01-25-2025 )Ken Worth Wrote:  On the cm870 there is 4 actuators, the very first one is fueling for the front 3 and the very last 4th in line, is for the rear 3 right?

Yes.......

it's possible you have a bad timing or metering actuator for the back 3 since you've found an issue on #4 but no bubbles.

Also look VERY close when barring the engine over, "bubbles" can be easy to miss. Watch Rawze's video(3 short videos) and you'll see what i mean.

https://youtu.be/Wu_WN8BA-LA?si=atQphHcIJ6w-xbb6

Thanks to Rawze and his videos is the only reason am even messing with any of this.

What do you guys think is this too much oil on turbo side feels caked up little wet.