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waverlybus
Senior Member
94 Posts |
 Posted - 05/03/2018 : 08:55:01 AM
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I am trying to find out how to test my 2012 ISB to see if the turbine seal is bad. I am getting random spikes in crankcase pressure that turn on the stop engine light. The driver then shuts the bus off and restarts and continues on his route. It will go off anywhere between once every few days to 3-4 times during a route, there is really no rhyme or reason to when it sets the fault. I have also noticed that when the driver brings the bus in from route and it is allowed to idle it produces a whistle in the exhaust between the turbo and the dpf for 10min or so then just stops. VGT going bad?
I have replaced the crankcase pressure sensor, tested the sensor voltage on Insite while pulling/wiggling the wire harness and plug end, I then gutted the crankcase breather and cleaned out the oil return lines from the ccf housing. I have also checked the turbo shaft for play and for oil entering the intake tubes. The Turbo shaft has a slight amount of side to side play but there is no oil entering the intake piping. The bus has 117k miles and the same driver has driven it since new and he has not noticed a loss in power nor any smoke from the tail pipe. Any guidance is appreciated. I do have Cummins Insite as well. Thanks |
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1Dieselman
Active Member
28 Posts |
Posted - 05/03/2018 : 09:10:56 AM
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| To be honest I've never known or seen turbo seals cause excessive crankcase pressure. I do know that bad engine mounted air compressors, hurt engine from overheating,dusted or lack of air filter maintenance will cause it. You might hook a manometer to the crankcase to find out exactly how much pressure you do have. Warning light is supposed to come on at 17.7 psi. I have one bus in the yard that has been severely overheated twice and had lack of proper air filter maintenance, gets up to 21 psi of crankcase pressure, turns on the engine warning very often but it still gets on down the road like nothing is wrong. |
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waverlybus
Senior Member
94 Posts |
Posted - 05/03/2018 : 11:55:58 AM
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| The air filters get changed twice a year, during summer and winter break. We put an average of 18-20k miles on a year with this bus. The highest recorded crankcase pressure is 28inH20 on Insite. The pressure required to turn on median range over pressure is 17.2inH20. There is another post on here recently with the same engine but it was a year older that found the turbo to be the issue when they had very similar symptoms. I tried commenting on the thread but have not gotten any response. All of the times I have seen issues with worn rings the crankcase pressure spikes under load at predictable times, but this one just seems to do it when it wants too, so it has me baffled. Runs great you would never know there was an issue till the buzzer comes on. |
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isb turbo test
