Tappet Insights Understanding Wear in HPFP Systems

Biodiesel deposits may form in the high-pressure fuel pump of trucks equipped with diesel engines, according to the NHTSA. states that the HPFP can fail due to low fuel quality, contamination, or wear and tear. This can result in reduced engine performance, misfiring ... So I pulled the high pressure fuel pump and as I removed it I made sure the roller follower didn't fall out... I pulled it out and then ... check out your high pressure fuel pump. and here's the big test. it actually shuts off. when you turn the key off. 27 Likes, TikTok video ... The shop manual indicates this may happen to the HPFP when reattaching the pump. The directions are to insure the flat part of the cam lobe is at the top. With the tappet worn completely through, your fuel pump actuator had to be riding directly on the cam lobe. I find it hard to believe there is no damage. The reason for this is aftermarket pumps use much stiffer springs, which massively increases the forces exerted on the tappet, wearing it out ... Yes, the HPFP is driven by a separate lobe on the cam. It's located on the passenger side valve cover. It's normal for HPFPs to make an audible ticking/ ... If it's blocked, maybe Brakleen or Gumout, something with solvent and pressure. If it's open and simply being maintained, I'd imagine regular canned air would ... How to inspect/replace the HPFP's lifter bucket on Gen2 Nissan Armada (2017+) & Infiniti QX56 (2011-2013) & Gen1 Infiniti QX80 (2014+).