As you all know, I’ve been working on my truck to beat the coking issues that present themselves while burning waste oil. I recently posted a video after pulling the injectors to show what my precups looked like. What I found was that the oil had not sufficiently burned and had completely filled the precups with solid carbon deposits. In most cases, the carbon even covered the tips of the injectors, only leaving a pinhole for the needle. This issue led to very poor combustion of even standard diesel fuels and resulted in smoking in most scenarios and very poor fuel efficiency. All of this is somewhat typical of coking.
As I stumbled through the process of pulling my injectors, disassembling, cleaning, rebuilding, and installing them, I tried my best to record the process so I could share it. The result was this: