ISX - Injectors Cutting out

[Rawze]

(02-19-2022 )azine Wrote:  2006 Cummins ISX CM870

Money was VERY likely wasted replacing injectors and/or actuators. Now moving forward I’d like to prevent any further bleeding from money wasted on parts and/or labor trying to determine what the problem is. I will get the software downloaded ASAP but I thought there might be a more simple reason than two different software programs.

The owner of the shop gave me the update after hours on Friday. The owner was not the one doing the assembly but I trust the guy doing it knew what he was doing up until this point.

Your words are just about exactly what everyone else that comes on here says. PPL always put way too much damn faith in "their mechanic/shop" and that is exactly what gets them into problems... and they are always quick to argue it away just like you have there... that is, until they start to learn the truth. There are just too many under and/or improperly trained repair shops for these ISX engines any more, it is as simple as that... and the people who do d-emandate programming are mostly nothing but a complete joke, and do not even know how the engine or its programming works .. but they are experts in copying garbage off of each other on those auto-tuning web sites like fools. ref: http://rawze.com/forums/showthread.php?t...5#pid13255


assuming for a moment that it has a rougher than normal idle...


FIRST ... if the engine has just been rebuilt.. it is completely normal for it to lope, run like crap, shake, etc.. for about the first 10-20 minutes after the fuel system has been all apart. It takes at least that long just to get all the air out of the fuel after any of that type of work has been done. Here is a nice example of what is typically seen on a fresh build at first crank: http://rawze.com/forums/showthread.php?t...1#pid27361

Assuming this is not the case for a moment... and that it really is a badly running...

As far as the rough idle.. your programming may or may not be the issue with that.. but you can be assured that having it checked out/reviewed should take the highest priority for the sake of the engine and to ensure you have a good base to go off of for troubleshooting the rest of it. - I don't care how much faith you have in the person who did that to it. It IS the biggest elephant in the room in your first post, and as such, should take the highest priority.

=====

also.. will it pass an injector leak test>?...
http://rawze.com/forums/showthread.php?t...8#pid67948

Injector leak tests, etc. should have happened instead of blindly replacing injectors + guessing like a fool!... because most shops these days that I have come across are completely clueless on how to do proper injector tests .. and resort to guessing and replacing s$it at YOUR EXPENSE instead of taking the proper steps to find the issues.

Also.. did anyone bother to replace the cam and crank position sensor during the inframe? ... and did anyone bother to ensure the tone wheel on the crank was not loose (had any play), or damaged in any way .. because those are also 2 more reasons that it would idle rough.

Also,... what wedge was used for the valve cam when the engine was put back together.. and what is the engine ser#?.. and/or its CPL#? on the valve cover?. Those CM870's require different wedges based on CPl... and many shops get it wrong when re-assembling that model engine.. so that is yet another concern.

Also, was the block counter-bored? .. and if so, what was the liner height on each cylinder set to?.. and did they let it sit over night and allow the head gasket to crush.. then re-torque the head-bolts next day a second time? .. because that liner height and gasket crush will make or break the longevity of the engine after an inframe, and all that money was either spent well.. or wasted because it may come apart again in a few years or less. ref: http://rawze.com/forums/showthread.php?t...5#pid41315

.. and what is the turbo/boost doing at idle when it is running rough?.. is the control arm moving around?.. or is it steady?

and has anyone bothered to do a compression leak test on it?..

or checked to see if a cam has slipped?...


Were the actuators actually checked before some fool blindly replaced them?...ref: http://rawze.com/forums/showthread.php?t...619#pid619

.. and were the new ones checked after the rough idle did not go away>?.

or an engine brake solenoid is not sticking>?

.. anyone bothered to inspect / replace the fuel solenoid dampers on the back-side of the IFSM if they are many years old, while the head was off of it?... or when the rougher then normal idle would not go away?.

Anyone bother to ensure it is not sucking air into the fuel system by pressurizing the fuel tanks + checking for leaks / dumping the inlet line to the fuel pump into a bucket to ensure a pick-up tube was not cracked at the top of the tank? ... or letting fuel go into a bucket at the compu-check port(s) and checking for bubbles??.

The problem may even be electrical... or even a bad ecm ... which in your case, you mentioned replacing with another one off another truck.. so hopefully it is not the ecm itself. ...

When is the last time someone went thru the engine and replace all the old sensors (that had more than 600k miles or several years of run time on them). Sensors like the intake pressure and temp sensors?... how about replacing the exhaust pressure sensor and ensuring the circuit thru the thermostat housing was not blocked up?. ... what about those disabled EGR sensors and the EGR valve?. - Just because they are disabled.. does not mean one cannot act up and throw the engine into chaos as they get really old and start to fail. What about the altitude sensor?, etc.

-- there are hundreds of reasons that would lead to a rougher than normal idle on an ISX CM870 ... you start with the obvious and work your way towards to the less obvious.. that is how its done.