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+--- Thread: Low EGT's 250°f wont regen (/showthread.php?tid=6692)
Low EGT's 250°f wont regen - AyronP - 10-12-2020
How's it going yall?
So I have this 2012 isx single cam that won't regen, I've been all over this truck, reman turbo, fixed a bunch of exhaust leaks, lots of back lash in the idler gears. It just won't get hot, and low exhaust pressure as well. Most of our trucks read 150inhg
When in regen but this one won't get over 40inhg. It had a 1921 code but when I blew out the dpf it actually went away on the drive back to the shop. I'm stuck.[/size]
RE: Low EGT's 250°f wont regen - Rawze - 10-12-2020
Almost all aftertreatment problems are a result of engine problems.
* Will it pass a rail leak test (less than 4,000 psi loss in 60 seconds)?
ref:
<iframe id="lbry-iframe" width="560" height="315" src="https://odysee.com/$/embed/isx-injector-leak-test-for-the-cm2250/e8187fb8d70f0f06388b597cb40751c5536d03dd?r=8p8MjqctPT8PafuYA5mftGueGF8L3how" allowfullscreen></iframe>
* Anyone verified the EGR valve is not stuck open?
* Anyone replaced the IMAP sensor, exhaust back-pressure sensor + its cross-tubing clear, other egr sensors like Delta-p, plugged, soot packed, old and in need of replacement, etc.? .. I.E.> An EGR tune-up for the enigne?
* Anyone verify the temps with a temp gun?
* When is the last time the Doser injector was replaced/cleaned. etc?
how many miles on the truck? engine? after-treatment components?
* .... blowing out the DPF is not a proper way to clean one.. it has to be baked, de-ashed, then flow-tested etc... along with the DOC element. This can be done at a stealers$it that has the proper equipment... there is no other way to properly clean one without causing it some serious harm.
* What is the oil and coolant consumption like? .. any excess blo-by?
* Anyone done a CAC and intake pressure test to ensure there are no egr or boost leaks?, new air intake filter, etc?
* when the turbo was installed, did someone just slap it on and do only the on-turbo calibration? -- or did they do it right and do the off-turbo calibration.. followed by the on-turbo calibration?
* Anyone verify the SCR element was not face plugged?
* Anyone inspect the decomp tube for the infamous 'Volcano' scenario?
ref: http://rawze.com/forums/showthread.php?tid=283
* overhead cam looks good?
* Overhead valve adjustment has been done within 250k miles and is correct?
-----
That is what comes to mind right away after reading your post. I am sure there is likely more. A healthy engine is the place to start for issues like this.
Also post a pic of the regen history, etc.
you also mentioned excess backlash in gears? -- you mean face gears for the enigne? which ones, and what is the backlash measuring? and why did someone have to measure this?. Are you getting cam and crank position sensor issues?.. or did someone mess with it?.. cuz those gears are not going to wear out unless the fuel pump fails and takes em oput.
Anyone inspect the fuel pump to ensure it is not destroying itself?.. Was it re-built/all its guts replaced at the 400k mile mark (or equivalent engine hours)?
There is a lot of care and maintenence that needs to go into a CM2250(2012) ISX engine. Most truck owners neglect 100% of it all until its way too late and all the problems set in.. then wonder why the thing will not operate correctly, the regen system is shot, and expensive components keep failing.
RE: Low EGT's 250°f wont regen - AyronP - 10-12-2020
Wow alot to unpack thank you very much.
The truck had the head and cam replaced about a year ago and the lash is on point. I can tell you as far as the sensors and tubes go they're good. The turbo was slapped on and the guy said he calibrated it properly but when I got my hands on it I had faults pertaining to the calibration. Can't remember what they were but I calibrated it correctly and it hasn't been a issue since. I agree the dpf has to be baked.
As far as the idler gears go they were very noisy. The spec on quickserve was .009 to .011
The best I could get was .016. The engine sounds good now. I was working on it a few hundred miles from the shop, they drove it back bobtail and in the regen history it shows it got one on the way. Check engine light is off and soot load is normal. But when stationary the exhaust Temps wont even try. I do feel like its a engine issue. Never got codes for a timing issue. However during the injector performance test 1st attempt it kicked out because the pressure was unstable the rail sensor had a cut wire on it someone fixed with a crappy butt connector so I replaced it. But thats before the test. Also when I preform the hysteresis test it fails 3 times and passes.
No boost leaks, good air filter. They hooked up a frac pump to it today and the driver said it drove awesome made good power. I did verify Temps with a temp gun.
RE: Low EGT's 250°f wont regen - Rawze - 10-12-2020
What is the leak rate then you do a rail leak test?
RE: Low EGT's 250°f wont regen - DieselKid - 10-13-2020
I think Rawze covered all the main things to look for. Just thought I would also mention the Regen Analyzer test in insite. We had one kickin our ass in the shop, kept failing for high percent load (20% during Regen, should be closer to 5) t/s for that led us to ipt test which failed a couple of injectors.
RE: Low EGT's 250°f wont regen - AyronP - 10-16-2020
That truck got put on the back burner.
I'm definitely gonna take another swing at it with that leak down test, I'll let you know. Thanks guys.