ISX 871 error 2449

[Rawze]

Only 28 psi boost is too low for a CM871.

* who did the de-mandate on it?.

* has anyone bothered to remove the down pipe for the exhaust and see if it gains more boost on a hard pull?.

* Has anyone bothered to check the intake, CAC etc. for leaks or to see if the CAC unit is leaky under 30 psi of air pressure?.

* Has anyone bothered to remove the turbo actuator and do a proper turbo inspection?... see if there is too much resistance in the arm movement vs. a new turbo?.

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You know, there was recently another person on here that had a de-mandate done.. it was done 100% correctly, program reviewed by myself to ensure this, .. and same thing. Engine went from making 36+ boost down to only 28 psi. No matter what, that engine would not make good boost after a proper de-mandate program was put in.


He kept swearing over and over that it was the program .. because he could put one of those trash garbage de-mandates in it that tear the engine up.. and the boost would be back u- to normal levels (because most bad deletes over-spool the crap out of the turbo, and this masked the issue).

Put the properly made program in it .. and it went back to low boost, power issues, etc.etc.etc..

I kept arguing with them .. over and over.. round and round we went.. him taking it to several different repair shops to try to find something wrong with that truck... did every test under the sun to it... and it recently also had a brand new (re-man) turbo put onto it too.

I must have check/reviewed his program 4 or 5 separate times with him just to be sure .. .. literally there was noting wrong with the program... but this person would not believe me to save his arsse by this point.. no one could find anything wrong with the truck.

I have to give him some credit though.. he did not resort to running the garbage-can delete .. he was bent on solving the issue rather than risk tearing up his engine.

About half a year went on of this .. and I would get phone calls where they tried all kinds of things to resolve it .. and no one could figure it out.. and all of them, always said that it has to be in the program.

I kept pushing back, and told him there are too many thousands of 871's running around out there for me to know better. If he drove it down here, I would help him find the problem... and for him to prove me wrong once and for all. - Problem is that he lived in northern canada... and never got down this way.

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He finally got fed up with it enough, he had his father drive the truck bobtail all the way down here from canada... as a last resort. When he got here a couple days later.

What we found ... His exhaust back-pressure sensor circuit was 100% completely clogged up where it went thru the thermostat housing. - i had already told him to check this.. and no one ever bothered to!. -= It was so bad, that we had to take a drill bit to it to clean it out. i had never seen one that bad before.. so surely, after fixing this, the boost would come back and the fuel mileage,.. etc. .. right?.


I took it on a single test drive and saw the low boost, power issues, etc.. all the problems, but i also showed him on the laptop screen that the ecm was crying about low boost (only 28 psi), but that also the turbo RPM was upwards of 121K rpm!> ... Clearly that turbo spinning that fast should have been making almost 40+ lbs.. but it was not!.

I told him that his re-man turbo was bad!.... of course, he did not believe me at all. He left and did not believe me. That turbo had gotten replaced dammit!>

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About 3 weeks after he left, he called me on the phone and asked me if I could turn down his boost tables.. as it was now over-boosting. -= He said that he purchased a certified re-man from cummins and all his boost problems went away and the truck ran great!. -= Apparently, this reman turbo he had purchased prior, was not a certified cummins, but something from a very well known turbo shop up there in canada that many people seems to use up there, and that it had the wrong exhaust housing on it, making all his boost etc. suffer.

-= the turbo shop refused to give him his moneys back.. and also refused to fix it ... and he only found out about it after sending that other turbo to YTS in griffin, ga. in attempts to save it.