Cummins ISB 275HP Engine Issues

[5343stk]

Help,

I have a Cummins ISB 275HP that is giving me fits.

About a month ago I was traveling home from a race and noticed my boost pressure was lower than normal and my EGT's were down. I noticed the lack of power especially. All of a sudden, the Stop Engine light came on and I coasted to a stop along freeway. Waited a few minutes, hit key and motorhome restarted. Made it home with no further issues.

Was moving motorhome last weekend and while backing into my shop, it did same thing. Restarted with no issue.

Purchased VMSpc from Silverleaf and installed today. Took on road trip to test. On my return home, I was bucking strong headwind and fighting lack of power. Boost was hovering around 18.5psi. All of a sudden, Stop Engine Light on and me coasting to side of road. Restarted and made it back home.

The VMSpc picked up the following codes:

ENG SID 251 3 Power Supply High Voltage
ENG SID 102 4 Boost Pressure Low Voltage
ABS SID 15 4 Relay Diagonal 2 Low Voltage

The motorhome starts and drives without much difference than originally. I do notice the lack of power / boost. I also am utilizing a adder from TST products.

Any have any idea's where I can begin??

Thanks

James Findell

[Triker56]

The VMSpc fault codes never are the same as Cummins numbers.

Your ISB should be putting out up to 23 PSI boost. Check for any loose clamps around the turbo. The hose going to the CAC for leaks.
Also there is a hose going to the compressor on the passenger side that sometimes it gets a hole in it and pressure/power will be lost.

Any of the fault codes can make the engine derate itself. Thus the shutting off.
And probably a reset when you turn key off and then start it back up.

[5343stk]

Thanks for your input.

What is the best way to check for leaks / fittings other than visual inspection?

I also forgot to mention that I have been experiencing an abnormal amount of fuel / oil on the front of my trailer. I thought it was from the slobber tube / turbulence.

[Triker56]

Has your slobber tube been extended down below the CAC?

I ran mine all the way down to my rear full mud guard. Very little oil comes out of it. I did have the oil breather for it replaced once. 1st time a coach care shop thought it was just a gasket and replaced it. After I left it still was leaking so I stopped into another coach care on the road.

Showed them my repair papers from the other shop. And they said the labor had a 6 month warranty and labor would be free. I just had to pay $46.19 for the breather part they found was the problem.

I don't know if you can feel any air loss with the engine running or not. You may from the smaller hose from the compressor. But the CAC will not have hardly any at idle. You may have to use a Cummins shop to find the problem with their Laptop code reader.