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TRex
Senior Member
89 Posts |
 Posted - 01/29/2020 : 06:16:54 AM
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| On other forums and sites I see articles about the problems carbon buildup causes in the intake passages of Gasoline Direct Injection engines(GDI) If I read these posts correctly this build-up can cause no code engine miss and stumble problems. The solution is to clean out the intake passages by various means. This is my question. Has anybody experienced this on a medium duty diesel engine? I have an International School Bus, vin CB396013 with a MaxxForce DT inline 6 cylinder engine EPA 2010 engine. We chased a miss/stumble problem through any and all diagnostic steps short of tearing engine down. Steps taken would be 2 paragraphs. We never found a cause. Has anybody seen the carbon soot buildup cause this on a MD/HD engine. TIA. |
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bwest
Administrator
United States
3820 Posts |
Posted - 01/29/2020 : 06:26:14 AM
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| TRex, I'm going to change the title of your post. My hope is that it will get more people to click on it and give you a hand. |
Bryan |
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Bluenozer
Top Member
Canada
644 Posts |
Posted - 01/29/2020 : 09:16:19 AM
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| EGR hot pipe clogged along the back of engine no codes and it will act up , ITV dosn't always set a code ( you can just unplug it and run it to see if stumble goes away) bear trap( cylinder used for heating emission up, or exhaust brake) on exhaust suck closed a bit, intake pressure sensor clogged up could be a lot of things |
OEM trained in wiring and all engine platforms for over 20 years
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TRex
Senior Member
89 Posts |
Posted - 01/29/2020 : 12:15:01 PM
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| Bluenozer, ITV and EGR valve new. Converted to open breather so cross tube is new. Bear trap working. Ran it with exhaust system off. Still missed. Garage states this has been an issue since cam replacement in 2016 or 16. Using NED's with CPA and BEAM all tests have been run. NAV Tech flat out states eng is in time based on results. From problems on other engines I believe they are right. Best I can do on timing w/o pulling front cover. Injectors replaced in Sep 19 because they were shorting. The miss is noticable, I have caught it on several snapshots. It's about a 200 rpm drop. Was going to put this on IATN but thats offline today.Reading about the GDI issues got me to thinking about that. Open to all ideas about this problem. |
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TRex
Senior Member
89 Posts |
Posted - 01/29/2020 : 12:17:59 PM
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| Bryan. Thank you. |
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Bluenozer
Top Member
Canada
644 Posts |
Posted - 01/30/2020 : 05:44:32 AM
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I would look at everything with cam then--
valve adjustments?
ensure roller lifters are in correct?
did the push tubes seat correctly?
did they double the dog bones? did a bone break and roller go sideways?
can't see it being out of time, pretty hard to mess that up?
or did the cam hardener come off again and a lobe is wearing or roller ? |
OEM trained in wiring and all engine platforms for over 20 years
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Edited by - Bluenozer on 01/30/2020 05:45:28 AM |
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td083
Senior Member
195 Posts |
Posted - 01/30/2020 : 05:45:31 AM
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| you may want to double check part numbers for the injectors that were installed , we have had one that the wrong injectors were installed went for a while like that and caused an issue similar to this just a thought |
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TRex
Senior Member
89 Posts |
Posted - 01/30/2020 : 08:27:37 AM
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| We checked valve adj when we did cylinder leakdown and physical comp tests. All valve adjs were in spec. Very aware of cam issues on these engines. Reminds me of 79/80 mess with poorly hardened lobes although this current issues is a bit dif. Cyl testing was ok. I have seen better but also much worse. So that is what lead to my plugged intake question. I may never know. Bus is back in service. They did not want to do anymore testing and I was out of ideas short of tear down. It runs fine other than this miss, which is slightly worse on a grade. |
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g0ttadrift
Advanced Member
USA
258 Posts |
Posted - 01/31/2020 : 7:10:20 PM
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| Not trying to beat a dead horse, but those Maxxforce DT's are prone to carbon buildup on the injectors. Do you know if changing the injectors solved the issue initially? I don't know how much of a difference this will make, but the new injectors need to be programmed into the ECM. |
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TRex
Senior Member
89 Posts |
Posted - 02/04/2020 : 11:53:49 AM
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| At this time this is a dead horse. Going to leave it "as is" for now. If I ever figure out an oscope there are some interesting pressure transducer readings that can be taken at the intake and exhaust. Might pin down the cylinder for sure. I don't think I will get further until we open it up. Thanks to all. |
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Engine stumble and miss (Maxxforce DT)
