Goddy454 Posted October 18, 2021 Share Posted October 18, 2021 Could use a little help with a regen issue. Truck is calling for a parked regen and it fails. The regen starts but after about 5 mins the idle becomes lopey and the exhaust temps only go as high as 360. While viewing the data in PTT i see the turbo only reaches a maximum speed of 22K RPMS and my EGR Diff pressure reads 1.5. With the truck at normal idle the turbo speed is 0 RPM. Besides a faulty turbo is there anything I should look for that cause the the turbo issue, and what can anybody tell me about the EGR Diff Pressure. I dont think that is normal, I did swap the sensor and it made no difference. Could my EGR valve be malfunctioning too. Thanks for any help anyone can give me. Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/ Share on other sites More sharing options...
Onyx610 Posted October 18, 2021 Share Posted October 18, 2021 EGR valve could be stuck open some and 7th injector could be dirty. We had one with a bad valve and it would fail regens and the dpf was face plugged. I was told one time from someone at Bergeys truck centers that if you take the egr pipe off that goes into the intake and if you feel pulsing/exhaust your valve is open. Just have to figure out when it should be closed to do that test. Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/#findComment-481541 Share on other sites More sharing options...
Goddy454 Posted October 18, 2021 Author Share Posted October 18, 2021 My temps aren't even getting high enough to activate the 7th injector. Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/#findComment-481551 Share on other sites More sharing options...
Onyx610 Posted October 19, 2021 Share Posted October 19, 2021 Could be a combination of a faulty turbo/actuator and maybe a discharge recirculation valve? Maybe the DOC is plugged up too? Hopefully some of the guys with a lot more knowledge on this can help you out. Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/#findComment-481557 Share on other sites More sharing options...
Joey Mack Posted October 19, 2021 Share Posted October 19, 2021 looks like you are holding the gasket for the 7th injector... the DPF has a boatload of soot on it as well.. What is going on before turbo pipe? I have used a lenth of .035" wire from a mig welder to rod out the DPF (gently) but never one a filthy as that one... Looks like re-gens were not completed.. I'm so rusty on these P.O.S. systems. are there any leaks around the sealing ring's? have you reused the rings and clamps and didnt get the sections connected good during previous dissassemblies? The slightest air/pressure leak can cause issues with the differential pressure sensors, both in the DPF and the EGR venturi pipe... there will be much smarter folks than me chiming in on this... Jojo Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/#findComment-481559 Share on other sites More sharing options...
Joey Mack Posted October 19, 2021 Share Posted October 19, 2021 Ooop's I should have paid better attention... I have made these mistakes a few times lately... I'm sorry... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/#findComment-481561 Share on other sites More sharing options...
Onyx610 Posted October 19, 2021 Share Posted October 19, 2021 Older style MP8, don’t think much has changed. This has some good info though. Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/#findComment-481562 Share on other sites More sharing options...
Goddy454 Posted October 19, 2021 Author Share Posted October 19, 2021 Can a stuck wide open egr valve seriously affect turbo speed? Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/#findComment-481569 Share on other sites More sharing options...
Onyx610 Posted October 19, 2021 Share Posted October 19, 2021 I’d say yes, being it’s essentially a boost leak. Kind of like a wastegate. Plus it will change the air fuel ratio. Probably why the idle seems different. You could have a bad actuator. Run some tests and see what you come up with. Post back with what you find and I’m sure some of the guys on here will be able to get you going in the right direction. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/#findComment-481570 Share on other sites More sharing options...
fjh Posted October 20, 2021 Share Posted October 20, 2021 22 hours ago, Onyx610 said: I’d say yes, being it’s essentially a boost leak. Kind of like a wastegate. Plus it will change the air fuel ratio. Probably why the idle seems different. You could have a bad actuator. Run some tests and see what you come up with. Post back with what you find and I’m sure some of the guys on here will be able to get you going in the right direction. Agree ! The turbo needs to spool to create heat for the regen if the EGR valve is held open whether being told to by the computer or by the turbo being stuck it cant do it! If the DP sensor Or The Ports are clogged under the sensor the egr valve will gradually l be commanded open by the ECU as it thinks there is not enough egr flow !this creates more soot yada yada Its a vicious Circle! this seems to be one of the most common causes of face plugging pf the dpf From what we see at our shop! Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/#findComment-481606 Share on other sites More sharing options...
Goddy454 Posted October 20, 2021 Author Share Posted October 20, 2021 I did clean the venturi tube ports and they good, i have the turbo off, seems like it sticks a little bit, doesn't freewheel as easy as i think it should,I didn't pull the actuator to check the gate. I have other trucks sitting around so i am borrowing some parts and running comparisons. I am still looking at things and will post back with results. Thanks. Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/#findComment-481607 Share on other sites More sharing options...
Goddy454 Posted October 20, 2021 Author Share Posted October 20, 2021 When you say DP sensor do you mean DPF differential pressure sensor or EGR differential pressure sensor? Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/#findComment-481608 Share on other sites More sharing options...
fjh Posted October 20, 2021 Share Posted October 20, 2021 1 hour ago, Goddy454 said: When you say DP sensor do you mean DPF differential pressure sensor or EGR differential pressure sensor? Thanks Egr Venturi tube! Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/#findComment-481612 Share on other sites More sharing options...
Goddy454 Posted October 23, 2021 Author Share Posted October 23, 2021 UPDATE - I replaced the EGR and all is well, Turbo speeds, temps and EGR values are where they should be. Regen idle is now stable. Thanks to all who helped. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/68511-2014-mp8-regen-issue/#findComment-481743 Share on other sites More sharing options...
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