OJ Avery Posted January 9, 2018 Share Posted January 9, 2018 Hi all. I have a 12 mp7 with US10 emissions that has some catalyst issues. Here's what's been done. New DPF, 7th injector ,doser, doser lines, doser pump, doser coolant lines, EGR valve , EGR venturi and EGR differential pressure lines and sensor. Here's the problem. After a few days it calls for a parked regen. Driver does it and then in 10 miles or so it asks for it again. What I have done, ACM learned data reset (I don't know if that was done when doser was replaced) and an After treatment Injector Adaptive Factor reset. (again I don't know if this was done when the 7th inj was replaced). It came into the shop today with no codes. soot level was at 4%. I put 140 miles on it today, half country roads , half highway. Soot level is now 40%. I had the ptt hooked to it and it never showed a rolling regen. 7th inj was never activated. My biggest question is does any one know at what point (soot level %) will a rolling regen happen and at what point (soot level %) does it call for a parked regen? And why would it call for a parked regen with a new dpf? Quote Link to comment https://www.bigmacktrucks.com/topic/52174-mp7-regen-issue/ Share on other sites More sharing options...
Mackpro Posted January 9, 2018 Share Posted January 9, 2018 It should try to start a rolling regen at 100 to 106% . And same with a parked. Was the soot ratio reset at time of DPF filter replacement? Bad turbo could be causing soot build up. Mack usually wants us to remove pipe from turbo to DPF and do a "snap throttle" test to see if the engine smokes bad when reving it up. Remember , if your having high NOX problems, the truck will ask for parked regens to read the NOX levels to see if its clean enough to keep it from 5 MPH derate. If your soot ratio is not high and its asking for regen then its usually NOX related. Quote Link to comment https://www.bigmacktrucks.com/topic/52174-mp7-regen-issue/#findComment-389350 Share on other sites More sharing options...
OJ Avery Posted January 10, 2018 Author Share Posted January 10, 2018 The soot ratio was reset at time of replacement. What would a NOX issue be? It was suggested to me late yesterday by a dealer mechanic to do a snap test. I was told I should see a small puff of black, then it should clear up. If not the issue is probably injector(s) over fueling, which makes sense if the dpf soot levels are climbing quicker than they should. Thanks for the info on the rolling regen though, that will be useful! Also I got the turbo to hit #42 of boost a few times which the only other times I've seen it that high was bad injectors OR new turbo w/ new injectors. Quote Link to comment https://www.bigmacktrucks.com/topic/52174-mp7-regen-issue/#findComment-389378 Share on other sites More sharing options...
OJ Avery Posted January 10, 2018 Author Share Posted January 10, 2018 So I did the snap throttle test a couple times. the first time I did it the engine was cold and it let out a good sized puff of white smoke, then nothing. Shut it off, sat for about a hour and did it again, no smoke at all. Then I ran it in the bay for about 30 minutes to get some heat into it. It got up to about 170 and I tried it again and there was nothing. I did a warm hold function test which we've found to be handy when suspecting injectors and that was good. I'm not sure where to look next. Quote Link to comment https://www.bigmacktrucks.com/topic/52174-mp7-regen-issue/#findComment-389402 Share on other sites More sharing options...
Les Ortiz Posted February 27, 2020 Share Posted February 27, 2020 How do you perform a "warm hold test" not sure, New to diesel long time mechanic Quote Link to comment https://www.bigmacktrucks.com/topic/52174-mp7-regen-issue/#findComment-443900 Share on other sites More sharing options...
mp8_macky Posted May 3, 2020 Share Posted May 3, 2020 the only way to get thosse us10 and us07 macks running right is deleting them. i did my entire fleet and zero issues since then. god knows how many times i was pulling my hair because of those fuckers. i recommend this company https://truckecmtunes.com Quote Link to comment https://www.bigmacktrucks.com/topic/52174-mp7-regen-issue/#findComment-450253 Share on other sites More sharing options...
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