Goddy454 Posted May 30, 2023 Share Posted May 30, 2023 You guys have helped me in the past, and i need to call on you again. I have a 2012 GU813 MP8 where my regens will not complete. They seem to cycle. When connected to PTT and running a regen all is good till DPF outlet temp hit 945 degrees, at this point the idle drops, recirc and fuel shutoff activate and 7th injector go inactive. When temps drop to about 850 the regen kicks back in. It will keep doing this and soot level will not drop causing truck to always seek a regen. When regen kicks out temp readings at DPF in is about 840 (sensor 2) and exhaust temp is about 640 (sensor 1). Any help would be greatly appreciated, btw, 7th injector is new OEM and filters were recently cleaned. Thank You Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/ Share on other sites More sharing options...
fjh Posted May 30, 2023 Share Posted May 30, 2023 Not guru how ever what is the fuel pressure during regen?I believe a stuck turbo can cause this issue as well!if any of the younger folk are around they may chime in on this! Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532205 Share on other sites More sharing options...
Joey Mack Posted May 30, 2023 Share Posted May 30, 2023 Where's Onyx?? Vmac and Mackpro probably know how to approach this one.. and then you add FJH... and well...... It's fixed.. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532207 Share on other sites More sharing options...
Joey Mack Posted May 31, 2023 Share Posted May 31, 2023 Well,, Hello there stranger...... Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532211 Share on other sites More sharing options...
Onyx610 Posted May 31, 2023 Share Posted May 31, 2023 1 hour ago, Joey Mack said: Where's Onyx?? Vmac and Mackpro probably know how to approach this one.. and then you add FJH... and well...... It's fixed.. I guess we should all move to a certain location and open a business. We would all be millionaires….If t2 gets around 950-990 it will knock out of regen and start up again once it cools down some. However you said your t2 never gets that hot. Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532213 Share on other sites More sharing options...
Joey Mack Posted May 31, 2023 Share Posted May 31, 2023 Were gonna get the band back together boy's... 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532214 Share on other sites More sharing options...
Onyx610 Posted May 31, 2023 Share Posted May 31, 2023 Have you done a learned data reset on the parts replaced? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532217 Share on other sites More sharing options...
fjh Posted May 31, 2023 Share Posted May 31, 2023 14 hours ago, Onyx610 said: Have you done a learned data reset on the parts replaced? good call Onyx ! Also do you have any exhaust leaks on the accordion tube ( common issue) or anywhere on the engine side of the of the system exhaust gaskets are another( common issue ) these things don't take kindly to exhaust leaks inspect that tube and gaskets closely ! Also check for broken bolts and cracking near the front of the intake Manifold! Just sayin! Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532225 Share on other sites More sharing options...
Goddy454 Posted June 1, 2023 Author Share Posted June 1, 2023 My fuel pressures at both the 7th injector and engine are fine just about 60lbs, I cant remember if I did the learned data reset but I will give it a shot anyhow, I know I did the 7th injector reset. There are no exhaust leaks either. And I will check the intake as I had 2 MP7's with cracked intakes. Any other suggestions I am open too, all ears. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532274 Share on other sites More sharing options...
fjh Posted June 1, 2023 Share Posted June 1, 2023 Are you able to update with your PTT ? Maybe do an up date! and try again I find it odd that that recirc valve is going off I always thought it was engaged to heat the air ! humm! Onxy Macpro your up! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532275 Share on other sites More sharing options...
Goddy454 Posted June 1, 2023 Author Share Posted June 1, 2023 Just out of curiosity and to make sure I'm reading them properly which temp sensor is which? Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532277 Share on other sites More sharing options...
Goddy454 Posted June 1, 2023 Author Share Posted June 1, 2023 I did update with PTT, and what I meant by going off was that it changed states, I get confused by what is considered open and closed with the green dot on PTT Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532278 Share on other sites More sharing options...
Onyx610 Posted June 1, 2023 Share Posted June 1, 2023 1 hour ago, fjh said: Are you able to update with your PTT ? Maybe do an up date! and try again I find it odd that that recirc valve is going off I always thought it was engaged to heat the air ! humm! Onxy Macpro your up! Yea DRV is for creating heat. Everyone is currently giving you the free and easy things to start out with, and it also helps us navigate you to hopefully a solution. Maybe run a regen and post a picture of temps. Also when did this truck start having regen issues? Anything done prior to that? 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532280 Share on other sites More sharing options...
Onyx610 Posted June 1, 2023 Share Posted June 1, 2023 Also what’s soot level and differential pressure sensor (delta p) at during regen? Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532282 Share on other sites More sharing options...
Goddy454 Posted June 2, 2023 Author Share Posted June 2, 2023 I came to work today to run the regen and snap some pics for you guys but the truck was out on the road. About 3 mo's ago the truck was calling for regens multiple times a day. When I looked at the truck I found that the regens were failing, not able to build up enough a heat. I found the 7th injector was crudded up and spraying poorly, tried cleaning it but that didnt work, so I replaced it. After that the truck had no problem building up heat and that's when the "cycling" problem appeared. So reading the boards here I found posts that mentioned there are 2 different injectors, I double checked my part numbers, and I do have the proper injector. I swapped out the injector with another new one, as we keep a few new ones on hand. Problem still exists. I will be back here at the job on Sunday and check the data and snap some pics. Thanks once again. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532333 Share on other sites More sharing options...
fjh Posted June 2, 2023 Share Posted June 2, 2023 On 5/30/2023 at 3:45 PM, fjh said: Not guru how ever what is the fuel pressure during regen?I believe a stuck turbo can cause this issue as well!if any of the younger folk are around they may chime in on this! Suggestion Take the venturie tube and def sensor off and clean them and while you’re at it blow out the egr cooler! Open the egr valve with ptt with enge running to blow out the crud ! 2 Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532345 Share on other sites More sharing options...
Onyx610 Posted June 2, 2023 Share Posted June 2, 2023 At this point with all these failed regens it’s possible the dpf is face plugged, this could have all started when the 7th injector went to shit. No need to go there yet though. Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532347 Share on other sites More sharing options...
Joey Mack Posted June 3, 2023 Share Posted June 3, 2023 I may not have paid good attention, but did he look inside the SCR for white deposits?? or is it the DOC?? dammit.. I need to stop trying to be smart on these... MP's SUCK!!!! Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532351 Share on other sites More sharing options...
Onyx610 Posted June 3, 2023 Share Posted June 3, 2023 (edited) Could do a crystal sub regen…MPs have very few issues compared to most others, we been through this multiple times…. Edited June 3, 2023 by Onyx610 Spelling 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532352 Share on other sites More sharing options...
Joey Mack Posted June 3, 2023 Share Posted June 3, 2023 Now here is a voice of reason... Mr, Onyx...He can guide you quite well.. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532353 Share on other sites More sharing options...
Onyx610 Posted June 3, 2023 Share Posted June 3, 2023 We need the grandmasters MackPro and Vmac on this too. 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532355 Share on other sites More sharing options...
Joey Mack Posted June 3, 2023 Share Posted June 3, 2023 Onyx,, you have a lot of knowledge,, you seem to stay gone too much.. Stick around... these guys need you as well.. jojo 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532357 Share on other sites More sharing options...
fjh Posted June 3, 2023 Share Posted June 3, 2023 12 hours ago, Joey Mack said: Onyx,, you have a lot of knowledge,, you seem to stay gone too much.. Stick around... these guys need you as well.. jojo 100 percent on that one Joey ! I know enough to be dangerous on this junk! 😡 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532378 Share on other sites More sharing options...
Goddy454 Posted June 4, 2023 Author Share Posted June 4, 2023 Good Morning, I have some pics available of a regen is ran, i will send them one at a time with an explanation of what stage I was at and observations I have made. Here is the first picture, this is when I started bringing the truck up to operating temp without starting the regen Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532453 Share on other sites More sharing options...
Goddy454 Posted June 4, 2023 Author Share Posted June 4, 2023 here is the second pic during initial warmup in the regen, before the injector activated Quote Link to comment https://www.bigmacktrucks.com/topic/72906-2012-mp8-cycling-regen/#findComment-532454 Share on other sites More sharing options...
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