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+--- Thread: CM870 power issues (/showthread.php?tid=8573)
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CM870 power issues - Zocaid - 11-21-2022
Is this fuel actuators or something else? Truck takes off and pulls sluggish and harder to shift gears after 2 days driving then clears up over the weekend after sitting two days. Almost seems like a boost leak but problem consistently clears up after sitting. It’s a head scratcher.
RE: CM870 power issues - Rawze - 11-21-2022
see if it will pass an injector leak test after when it is acting up...
ref: http://rawze.com/forums/showthread.php?tid=7747&pid=67948#pid67948
also, what is the boost doing when this is happening?..
and also.. does it have a delete program in it?.. If so then you need to have the program checked out right away to ensure it is not harmful or causing it to jump engine operating modes improperly. - 90%+ of all delete programs are very harmful to the engine, even if the power was not touched.
RE: CM870 power issues - Zocaid - 11-21-2022
Appreciate it Rawze,
Truck is not deleted, and boost doesn’t change when the issue starts. It feels more like the engine is choked up starting even from takeoff. Truck shakes when I left off the clutch like I’m in way to high of a gear. Starts out slow and don’t gain much ground from 3-7 gears and when I let off the gas the engine pulls me back almost as if the Jake’s are on but they aren’t. But on a day like today it ran smooth as butter and has great acceleration between gears
RE: CM870 power issues - Zocaid - 11-21-2022
(11-21-2022 )Rawze Wrote: see if it will pass an injector leak test after when it is acting up...
ref: http://rawze.com/forums/showthread.php?tid=7747&pid=67948#pid67948
also, what is the boost doing when this is happening?..
and also.. does it have a delete program in it?.. If so then you need to have the program checked out right away to ensure it is not harmful or causing it to jump engine operating modes improperly. - 90%+ of all delete programs are very harmful to the engine, even if the power was not touched.
And I forgot to add. I have 26k on a long block from Cummins. I had the same issues with the last motor.
RE: CM870 power issues - Bengy88 - 11-21-2022
Do you have insite? If so ill be happy to help you figure it out one evening.
RE: CM870 power issues - Truckdriven - 11-22-2022
I had a CM570 that would have very random low power problems, It was a bad barometric pressure sensor. There were no fault codes but I found it by reading the sensor value with Insite, at my location should be around 31inhg but was reading 6 ingh.... Just a suggestion
RE: CM870 power issues - kamiar - 12-06-2022
Hello all, We have a CM870, 565HP, all stock, on an engine dyno that is been calibrated recently, it makes close to 700HP and Pyro jumps to 1060F under full load, all sensors reading seems in range, new injectors, turbo, egr valve, etc, tried older calibration as well as latest, AB10352.23, when i am think about it, i had at least one more stock CM870 and that was also making around 680-700HP on the dyno, we have a straight pipe exhaust system on the dyno, any ideas?
RE: CM870 power issues - Rawze - 12-07-2022
(12-06-2022 )kamiar Wrote: Hello all, We have a CM870, 565HP, all stock, on an engine dyno that is been calibrated recently, it makes close to 700HP and Pyro jumps to 1060F under full load, all sensors reading seems in range, new injectors, turbo, egr valve, etc, tried older calibration as well as latest, AB10352.23, when i am think about it, i had at least one more stock CM870 and that was also making around 680-700HP on the dyno, we have a straight pipe exhaust system on the dyno, any ideas?
sounds to me like the dyno is not showing you the correct numbers.
What is the fuel flow and boost pressures/.. mg.stroke during testing?. Without a lot more fuel, it will not do those numbers. Gureatee you that if the fuel flow is what it should be for 565hp, then the dyno is lying to you. That or you need to call every scientist on the planet and tell them that your engine breaks the laws of thermodynamic and you now have proof that aliens exist!.
RE: CM870 power issues - kamiar - 12-07-2022
(12-07-2022 )Rawze Wrote:(12-06-2022 )kamiar Wrote: Hello all, We have a CM870, 565HP, all stock, on an engine dyno that is been calibrated recently, it makes close to 700HP and Pyro jumps to 1060F under full load, all sensors reading seems in range, new injectors, turbo, egr valve, etc, tried older calibration as well as latest, AB10352.23, when i am think about it, i had at least one more stock CM870 and that was also making around 680-700HP on the dyno, we have a straight pipe exhaust system on the dyno, any ideas?
sounds to me like the dyno is not showing you the correct numbers.
What is the fuel flow and boost pressures/.. mg.stroke during testing?. Without a lot more fuel, it will not do those numbers. Gureatee you that if the fuel flow is what it should be for 565hp, then the dyno is lying to you. That or you need to call every scientist on the planet and tell them that your engine breaks the laws of thermodynamic and you now have proof that aliens exist!.
I hear you, we run a lot of engines on this dyno and they all make the exact hp that they are supposed to, only these CM870 CPL 8018, boost is 32PSI full load, fuel flow i am not sure but i will look again and report here, btw the timing and metering actuators are replaced as well...