As part of my engine part replacement project, I decided to address the black stuff that has accumulated in the upper intake plenum of my VG33E. At first, I was thinking that it was caused by a faulty PCV, but the valve appears to be functioning properly. Intake ports 4, 5, and 6 were not nearly as bad as 1, 2, and 3, and the source of carbon appears to be the EGR. I posted about this a while back, but wanted to give the thread a bump.
The buildup was the consistency of baked tree sap, and carb/choke cleaner barely put a dent in it. With the recommendation of a local parts store guy that I trust, I used oven cleaner, and it worked beautifully. Intake is nearly spotless now. The question is . . . is there something wrong with the EGR that is causing this buildup? The plenum was a PITA to remove, so I'd rather correct the underlying issue while I have everything apart.
The buildup was the consistency of baked tree sap, and carb/choke cleaner barely put a dent in it. With the recommendation of a local parts store guy that I trust, I used oven cleaner, and it worked beautifully. Intake is nearly spotless now. The question is . . . is there something wrong with the EGR that is causing this buildup? The plenum was a PITA to remove, so I'd rather correct the underlying issue while I have everything apart.