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Tim
Tim, Diesel Mechanic
Category: RV
Satisfied Customers: 356
Experience:  23 Years of Diesel Engine , Powertrain, and Electrical repairs
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cummins 450 hp 9.2 isl turbo charged, boost appears to be not

Resolved Question:

cummins 450 hp 9.2 isl turbo charged, boost appears to be not working. in the past boost would indicate 15 to 20 lbs now it only shows 5 to 10. engine only has 19k miles. application is 40 foot motor home 36k weight. any idea what to look for?
Submitted: 5 years ago.
Category: RV
Expert:  Tim replied 5 years ago.
<p>Hello, welcome to JA, my name isXXXXX will try to help... the boost has gone down 1/2.. the first step will be to determine if its the gauge/sensor or it has lost boost pressure.. if you only have 1/2 of your boost , should have low power and black smoke? Are you haveing performance problems?. also can you supply engine ser#</p><p> </p><p>Tim</p>
Customer: replied 5 years ago.
no black smoke but has lost power mainly when needing power for hills and when entering freeway. will have to get info for engine ser number
Expert:  Tim replied 5 years ago.

Hello, thank you for that...ok well the engine may be compensating for loss of boost and not over fueling causing black smoke.. So as far as boost loss..we want to start at the air cleaner make sure its clean, from there we would look at the piping and any hoses to the turbo, any hard bends or smashed would cause restriction, also if the hoses are to soft they can colapse... the turbo blades need to be inspected for damage and see if its spinning freely, with little play. out of the turbo, we want to check any and all piping for leaks going to the cooler and also back to the intake, ( the intake is were the boost sensor will be) .. The best way to check this piping for boost leaks is to make up a spray bottle of soapy water... in small sections, spary down the pipes and have someone run up the throttle and look for bubbles, these would be boost leaks.. check all the hoses and the cooler at seams in small sections, till you check it all.. this is were I would start.. when you get the ser# XXXXX can take a closer look too..let me know

 

Tim

Customer: replied 5 years ago.

Tim,

 

Thank you for the info and what to look for. The first thing I did was change the air filter and crossed my fingers for improvment. I now have more things to look into and i will get the ser # XXXXX today. However I will accept your information and start the hunt.

 

Thank you for your time.

Expert:  Tim replied 5 years ago.

Ok , Very welcome..yea just reply back when you can its 1030 at night for me but I will check back in the AM..

 

Tim

Customer: replied 5 years ago.

Hi Tim here is the ser # XXXXX MFG Date 10/96 sold to Monaco Coach co. Cummins M11 450E

Expert:  Tim replied 5 years ago.

Hello, Thank you for that.. I will be able to look some things up knowing its a M11 but any chance you could get me the engine ser# XXXXX will just be a 8 digit number...did you have a chance to look at the things I spoke of before.. because they will be your most likley...I am almost off work and will have more time in about a hour..

 

Tim

Customer: replied 5 years ago.

ok I have the numbers 34839377 The soap trick works there is a leak where the tubing flares out to the radiator. it appears that the unit has had problems here before as there is alot of rubber type sealant at this junction. the 7 rubber boots do not leak and do not appear to be collapsing.

Expert:  Tim replied 5 years ago.

Ahhh.. that sounds like it that is your air cooler, thats were you are loosing the boost then and under a load it would even be worse.. some places can repair them , but normally its just replace. either way it will have to come out....good job on finding it..

 

Tim

Tim, Diesel Mechanic
Category: RV
Satisfied Customers: 356
Experience: 23 Years of Diesel Engine , Powertrain, and Electrical repairs
Tim and 3 other RV Specialists are ready to help you

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