Rawze.com: Rawze's ISX Technical Discussion and more

Hi Guy's
Awesome bunch of folk on here, good blog to have a membership going! Hotsauce or not...

I have a problem with a CM871 ISX engine. Initially it cooked 3 x ECM when Cummins had a go at it and it turned out that on DPF regen the ECM was getting a back feed power surge frying them all up.

I sent my guy an exchange ecm with egr and dpf deleted ( I am in New Zealand so this is not a problem) and it has all the @m*m^2 goodies, including a 660 Hp tune. Worked fantastic, and no more ECM issues.
Initially it went fine and was great on fuel and power. This was beginning of January 2016.

In the last month it has gradually lost more and more power and started using more and more fuel.
It was using about 5 MPG (2 Km per liter) which is quite good for here, now it is down to 2.9 mpg (1.2 km per liter). No turbo or intake or inter cooler issues, this was checked by a local Cummins dealer who seemed knowledgeable on the phone.

Any idea's before I send the guy another ECM to make sure it is not an ECM problem?
I am thinking fuel pressure / fuel flow?
Thanks in advance.
Jack

I would be interested in where the boost and egt's are. If there is little change in that area then....because it had a harness issue before.....would go over the harness to make sure everything is ok. It sounds like some hardware didnt agree with the HP level and is starting to protest. How big is the hole in the DPF? Is exhaust getting out as it should? An EGT gauge would show exhaust back pressure in degrees if there is a problem in the exhaust system. 2.9 mpg for a mm871 is a VERY low figure. Also is the dozer valve completely shut off? Could it be pumping fuel into the exhaust stream? Just sayin.

(03-03-2016 )Optimanzltd Wrote: [ -> ]Hi Guy's
Awesome bunch of folk on here, good blog to have a membership going! Hotsauce or not...

I have a problem with a CM871 ISX engine. Initially it cooked 3 x ECM when Cummins had a go at it and it turned out that on DPF regen the ECM was getting a back feed power surge frying them all up.

I sent my guy an exchange ecm with egr and dpf deleted ( I am in New Zealand so this is not a problem) and it has all the @m*m^2 goodies, including a 660 Hp tune. Worked fantastic, and no more ECM issues.
Initially it went fine and was great on fuel and power. This was beginning of January 2016.

In the last month it has gradually lost more and more power and started using more and more fuel.
It was using about 5 MPG (2 Km per liter) which is quite good for here, now it is down to 2.9 mpg (1.2 km per liter). No turbo or intake or inter cooler issues, this was checked by a local Cummins dealer who seemed knowledgeable on the phone.

Any idea's before I send the guy another ECM to make sure it is not an ECM problem?
I am thinking fuel pressure / fuel flow?
Thanks in advance.
Jack

660 HP in constant high torque applications = short engine life.

I would ensure the doser is not leaking fuel. Cap the line if needed.

I would also agree that pyro gauge on the exhaust manifold and a boost gauge would absolutely be necessary to ensure it is running like it should.

here is video of how we do them over here...

I would start with a new imap and exhaust back pressure sensor... Also, has all the carbon been cleaned out of the intake? I'd also check the cam timing to make sure one hasn't slipped at all