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+--- Thread: Isx detuned? (/showthread.php?tid=3798)
Isx detuned? - MKCgrainhaulers - 11-27-2018
I'm sure this has been asked 10,000 times on this forum, but here goes again. My father an I are farmers in the rural midwest. We own a couple trucks that pull 40' hopper bottoms every fall hauling grain to the elevator. We recently purchased a 2004 International 9200i with a Cummins reman isx cm870. Motor has less than 15,000 miles since install. We were anxious to see what the isx could do. "Supposedly" its hp rating is 450 with 1650 torque. We know what 450hp and 1650 ft lbs of torque feels like and this thing falls short. Gearing is good (cant tell you exact ratio) but its turning roughly 1800 rpm at 65 to 70mph. We installed boost and pyro gauges prior to this years hauling season just to keep our eyes on internals. Now, before the bashing begins I'd like to state that I am not on here to turn this thing into some kind of smoking monster. That being said here's the problem. When fully loaded the truck is or should be grossing 80,000 lbs. And on a 2 mile hill, fully loaded, the boost will climb to 32lbs and stop instantly and will climb no more. Also the pyro will climb to 800 and will stop climbing as well. Never getting any hotter. Yes, normally that is a good thing but that's when we really need that 450hp to pull us the rest of the way and it seems to hit a wall and will pull no harder. In other instances such as taking off from dead stop empty or loaded it seems to do the same thing. Power is felt at very low rpms and the same wall is felt. It's almost as if it has the potential but something is holding it back. We are very mechanically inclined. My father has been a mechanic for over 30 years but on mostly no computer controlled diesels when it comes to heavy trucks. One more thing to add. We found out from the dealer that we purchased it from that the truck had spent most of its life used in the Walmart fleet. Do they detune their rigs? Is there somewhere we should look? Or is this the nature of the Cm870 isx? Any input would be very much appreciated. I know that was long and drawn out but I know more info usually helps. Thanks guys
RE: Isx detuned? - Lonestar10 - 11-27-2018
i know when i worked for crete when we moved from 62 to 65mph they didnt just change the speed limiter they had to put a whole new fuel table in the trucks so its possible it has an adulterated fuel table. your dealer should have installed an owner/op tune in it before he sold it to you.. i would go to said stealership and ask them to make sure the tune is an actual cummins tune not something some desk jockey thought was a good idea.
RE: Isx detuned? - Rawze - 11-27-2018
(11-27-2018 )MKCgrainhaulers Wrote: ...
the boost will climb to 32lbs and stop instantly and will climb no more
...
It could be turbocharger related...
-- It could be the turbocharger is out of calibration, the air operated controller is going bad, or the filter that supplies air to it is clogged.
What you describe though, is more like the classic symptom of a CM870 silent boost derate. The boost should be 36+37~ish psi.
There are a few reasons for this derate.
Most of the time on the CM870's as a result of someone disabling the EGR in some way and not re-programming it (or not programming it properly) for such things. In this case, the EGT's are usually higher then normal. It sounds like yours are lower than normal.
It can also happen if the ECM fails one of the fueling, metering, or fuel shutoff solenoids. Usually, you get an intermittent/occasional code for one of these components this in the fault history, but on rare occasion, you only get the derate without the code. This can cause lower then normal EGT's as well, as the injection timing could be off.
The engine may have the wrong program in it, or the injection cam timing may be off. - The CM870's in particular have different overhead cam mechanical offsets depending on CPL and ser# range. If someone has the wrong program in it, or if the engine was build (or re-built) with the wrong cam offset, it can throw off the injection timing and other things, making it not run as good, have power losses, have high injection timing leading to lower than normal EGT's, or a host of other minor issues.
I.E.> Only ever reaching 32 psi boost max on a CM870 in particular is a sign that it is not getting full power for some reason or another.
* Check that the overhead cam timing is correct for the CPL / ser# of that engine by wedging the cams and checking it. Re-adjust the overhead valves while your in there, as things could have settled since the initial build.
* Ensure there are no codes for any timing, metering, or fuel shutoff actuators in the fault history.
* Ensure the program matches the CPL and ser# for the engine.
* Ensure the turbo arm is not hanging up or something is causing it to not operate in its proper range.
* If the EGR is disabled on it, then ensure you have a program by one of the guys recommended on here (mommaburt / Unilevers) that tune CM870's specifically, otherwise, your likely to have a bad CM870 program. Most of the bad delete programs will do similar things to what you describe or other similar things.
* Make sure there is no air in the fuel, etc. causing lower than normal power.
* Do an injector leak test on it to ensure your not getting combustion gases back into the fuel system, leading to fuel-starved injectors.
Just some blind guessing here while drinking some coffee, nothing more.
RE: Isx detuned? - Rig Wrench - 11-27-2018
Didnt Wal-mart and possibly a couple of the other mega fleets have their own cals for there fleets? I feel like I recal ups having some obsurd 250 hp cal specifically for their trucks in an attempt to maximize fuel efficiency.
RE: Isx detuned? - DLC - 11-28-2018
The IH trucks has those one piece metal boot clamps that are prone to leak. Check your boots and intercooler for leaks. If you remove the EGR intake horn from your intake you'll wonder how it made 450 hp with that in there.
RE: Isx detuned? - Chamberpains - 11-28-2018
The way you describe your RPMs at 1800 doing 65 to 70 miles an hour tells me your rear end gears are 4:10's or better. That does not sound like a Walmart fleet truck at all. They gear their trucks with crazy low ratios in the rear. It sounds like you may have got your hands on someone that leased their truck to Walmart. That thing should be a pulling beast going up hills.
What you could also be describing is a torque limiter. I know on my 06 ISX I can set the heavy and light torque limiter at 1750 RPMs and it will fall flat on its face exactly at that RPM. you could also have the gear down protection enabled. There are a couple different torque limiters on your engine. And it wouldn't be unlike Walmart to set their trucks up to have all of them. You may want to invest in Cummins insite to check and change these governors if they're set. Also you'll be able to see if it's silently derating or going into an active derate under acceleration. it's well worth the money to invest in it so you can watch what's going on and keep your money in your pocket. It's a relatively simple program to figure out especially on your engine. And will help you diagnose the many many many other problems that may arise.