2012 Kenworth T800 - Heavy Smoke on Accel - SPN 102 FMI 2 Boost Pressure

Question

My ISX15 is rolling coal like a teenager's pickup every time I gear up under load. It feels sluggish and the turbo sounds like it's whistling more than usual. I pulled the code SPN 102 FMI 2 which I know is Intake Manifold Pressure.

I inspected the CAC hoses and they seem tight. I don't see any obvious tears. I replaced the boost pressure sensor on the intake manifold but the problem is still there. Could it be a stuck VGT actuator?

HighwayHelen · Accepted Answer

✅ Confirmed fix: Found a massive crack in the Charge Air Cooler (CAC) on the bottom tank. It wasn't visible from the top. I did a pressure test using a soapy water bottle and it was bubbling like crazy at 15psi. Replaced the CAC and the smoke cleared up and boost returned to 35psi.

FleetOwnerFiona · Answer

Check your EGR valve. If it's stuck open, you're recycling exhaust gas when you should be getting fresh air, leading to black smoke and low boost readings. You can pull the pipe and see if it's full of soot.

2012 Kenworth T800 - Heavy Smoke on Accel - SPN 102 FMI 2 Boost Pressure

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