lmorris Posted February 12, 2015 Share Posted February 12, 2015 We had a newer 6.7L in the other day that the other tech was looking at. He had the oil fill cap off and called me over to help evaluate the amount of blow-by coming out, very similar to a dusted 6L. Being that there is no documented crankcase pressure test for this engine, and I can't find anything on the crankcase pressure sensor except for in wiring diagrams, has anyone here managed to find out any info on crankcase pressure or ran into a situation where high crankcase pressure needed to be verified? On the older version I know they used MAF to determine crankcase pressure, has it changed with the introduction of the new sensor? I can't even find any pids or reference values. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted February 13, 2015 Share Posted February 13, 2015 The crankcase ventilation sensor monitors the crankcase ventilation hose connection at the air inlet of the turbocharger. The crankcase ventilation sensor signal to the PCM indicates if the crankcase ventilation hose is connected or disconnected. It first appeared on 2013 model trucks with 6.7L Power Stroke engines. I recall replacing one early on that had failed. From what I read on this (and understand) is that it only monitors whether the vent hose is connected and does not actually monitor crankcase pressure. The Cummins 6.7L ISB engine DOES have a functioning crankcase pressure sensor. Which I am sure you are not confusing here. I just wanted to throw that tid-bit of information in. Quote Link to comment Share on other sites More sharing options...
lmorris Posted February 13, 2015 Author Share Posted February 13, 2015 Thanks for the info. Quote Link to comment Share on other sites More sharing options...
forddieseldoctor Posted February 15, 2015 Share Posted February 15, 2015 On the older version I know they used MAF to determine crankcase pressure, has it changed with the introduction of the new sensor? I can't even find any pids or reference values. Is there anything they don't try to use MAF for? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted February 15, 2015 Share Posted February 15, 2015 On the older version I know they used MAF to determine crankcase pressure, has it changed with the introduction of the new sensor? I can't even find any pids or reference values. I am having trouble with this statement. I do not see how you can accurately measure crankcase pressure with the MAF sensor. Perhaps "detect" the presence of excessive pressure but not measure it by any means. The air management and exhaust systems on these engines have a lot of things going on. I know that engineering has been able to map data samples from various sensors and match it with certain conditions so I think it is reasonable to expect that MAF can detect the presensce of excessive crankcase pressure but not measure it. I cannot find anything in print in the related literature to support or refute this however. So now my mind has this question nagging at me. Thanx! Quote Link to comment Share on other sites More sharing options...
lmorris Posted February 17, 2015 Author Share Posted February 17, 2015 On the older version I know they used MAF to determine crankcase pressure, has it changed with the introduction of the new sensor? I can't even find any pids or reference values. I am having trouble with this statement. I do not see how you can accurately measure crankcase pressure with the MAF sensor. Perhaps "detect" the presence of excessive pressure but not measure it by any means. The air management and exhaust systems on these engines have a lot of things going on. I know that engineering has been able to map data samples from various sensors and match it with certain conditions so I think it is reasonable to expect that MAF can detect the presensce of excessive crankcase pressure but not measure it. I cannot find anything in print in the related literature to support or refute this however. So now my mind has this question nagging at me. Thanx! My bad. That was worded wrong. They use MAF readings to try and determine a fault in the crankcase ventilation system, not actual pressure. It's in description and operation in PCED. Still doesn't help me determine if that truck has high crankcase pressure though. Quote Link to comment Share on other sites More sharing options...
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