X15 possibly dropped liner? input please

[Rawze]

I was sent the program out of his truck today. Here is what was found on a review...

* There are some minor discrepancies in the program + some block codes used because of it. Not harmful to the engine itself, though they can be corrected, but a Couple of those block codes, I would have suggested avoiding. One of those codes was that they blocked error code 285. With error code 285 blocked, any number of dash switches like cruise control, engine brake switch, etc.etc.etc. can go bad and stop working,.. but will not throw any codes into the ecm/dash if this code it blocked. - As an example, It would be a troubleshooting night-mere for a mechanic somewhere in a shop to figure out why say the cruise control is not working if the cc switch itself had gotten re-assigned in the ecm or if the switch went bad/stopped communicating. This would go for about a dozen other switches and systems too. Not very good to block error code 285, as it effects a lot of sub-system communications and its errors. there are a couple other block codes i do not agree with, but they are not nearly as bad.

* The bulk of the rest of the program is quite impressive however aside for a couple red flags, so I will give credit where it is due before mentioning these red flags. - the engine is correctly mapped into its non-egr operating modes, all aux emissions systems have been properly taken care of, and the myriad of things that would cause harm like injection timing was within safe boundaries (although a degree or so higher than I like to see it for that X15 style compression ratio, no big deal ), power, torque all good, etc. ... all set within bounds. - this is a stark contrast from most programs that people send me, is nice to see for a change. Whoever made this program ... overall did a real swell job on it, and a lot of time and effort was put into making it right. ... HOWEVER THOUGH ... (couple red flags, and they are pretty big ones)...

* Red Flag#1: The boost pressure is set to peak as high as 36-37PSI in places. -- For an X15 efficiency series,.. This is TOO MUCH BOOST,.. and can eventually cause a liner issue or a cracked piston. MAX boost on an X15 efficiency series is about 28, maybe 31 psi MAXIMUM!. <-- Was this the cause of the premature liner issues ?-- It would be speculation to conclude that it was a causation, but boost set too high for the power/torque certainly did not help it, as it could have been a contributing factor. It was not set ridiculously high (I have seen programs that were far worse),.. but is certainly set in the lower edge of the danger zones.

* Red Flag#2: Engine brake settings were adjusted and made significantly stronger. THIS IS USUALLY DANGEROUS FOR THE ENGINE AND HEAD. - When engine brake settingsd are set higher, all it would take is for a driver to end up at 1900 or 2000 rpm going down a mountain and engine brake on highest setting,.. and there is extremely high potential for a valve to strike a piston, cracking the head or destroying the engine. <- THIS SHOULD NOT BE DONE!. - A closer examination shows that the engine brake was made stronger only in the lower RPM ranges,.. not as bad ... but they are set 98+% closed (up form the factory 70%), completely choking off the exhaust badly. - This is a bit too high, even for low rpm ranges and can cause some problems for the engine, the exhaust manifold gaskets, and for the turbo.

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All in all, the program can very easily be fixed as it is. The bulk of it is really nice and well done overall. - Simply putting the engine brake settings back where they belong and lowering the turbo tables to peak a few psi lower, and the program would have been 100% set towards not being harmful/hard on the engine.

Perhaps drop the injection timing a degree (maybe 1.5~ish) or so just to play it safe to help protect the engine a bit more next go around. NO injection strategy was adjusted to go with the maps that someone used, and it is a bit high for a 500+ hp engine being run fairly hard, but not completely out of bounds. This would be a good move to do this since it did in fact loose a liner prematurely just as a safety precaution. I do not think this was necessarily a contributing factor in having a liner issue, but lowering it a bit would make it a bit less chance towards possible future problems.

Note: 1 degree of injection timing is actually more like 1.6 or so degrees on older model engines. The X15 injection timing is quite sensitive compared to older trucks.

It looks a lot like someone perhaps simply copied/used CM2250 turbo mappings and copied some CM2350-X101 injection timing tables?. - Neither of those tables are compatible with an X15. CM2250 turbo mappings are definitely too strong for it, and the 2350 injection timing .. well is pushing it a bit, but not out of bounds with more appropriate injection strategy settings, but strategy was nit touched. - With 500+ HP,.. it could be risky, but only some testing and boroscoping engine after a while would reveal how risky it may be for it.

Overall,... Did the program cause its premature demise? -- boost + and extra degree or so injection timing (though timing was technically inside its safe zones) .. It is definite that it was not set towards minimizing this possibility,.. the excess boost certainly would make it run a bit lean, kinda hard on the liners and pistons, ... but to conclude that the failure was caused solely by the programming is a stretch considering it was not extreme. Especially since the engine's lifetime avg. load shows almost 40%,.. and this is higher than most highway trucks where they tend to hang around the 28-30% mark. -> 40%+ is typical of heavy haul highway trucks,.. or truck geared too tall and someone lugging it hard a lot of its life. Those factors alone could contribute heavily towards it loosing a liner at 500k. All of these issues and contributing factors can be resolved and avoided, absolutely. It just takes implementing the suggested programming changes, perhaps re-gearing the truck if need be for the heavier operations if that is what the truck is doing, and absolutely driving it in the right ways (Avoid heavy torque/lugging it below 1500rpm, keeping it above 1500rpm when heavy on the fuel pedal).

I would be curious to what kind of freight, weights, rear ratios, etc. too.

Also,.. picture are worth 10,000 words. Taking good clear pics of the bottom side of the head at each cylinder + a pic of each piston and cylinder BEFORE they are cleaned up (only dried off with paper towels) is worth gold towards the story of what might have caused its premature demise.