Dec 1, 2022, 09:15 PM

Well since you asked.

See Bosch's report on diesel fuel lubricity here. Why do we care what Bosch thinks? They manufacture our CP4 high pressure fuel pump that Ford uses. The lubricity measurement is done using a standard HFRR test that in simple terms intentionally creates friction between a ball bearing and a plate in a controlled fashion with diesel fuel as a lubricant, and then measures the resulting wear scar. For rated service life of Bosch high pressure fuel pumps they prescribe a maximum wear scar of 460 micrometers.

Fuel manufacturers use the exact same test as one of the benchmarks for target performance when they formulate their fuels. However US manufacturers target a test result of 520 micrometers, which is a result that Bosch has concluded is not good enough. As a result you can expect the service life bell curve of all Bosch's high pressure fuel pumps in the US to shift shorter, resulting in more premature failures. This study was done back in 2003 and predicted what we see today across all of the big 3, a too-common premature failure of CP4 HPFPs.

Ford will never ever admit that they know the pumps they're using with the fuels we have available are a combination more likely to fail prematurely. Even offering lubricity additives would effectively be admission. That would be begging for a very expensive class action lawsuit. Feigning ignorance gives room for benefit of the doubt which in the grand scheme is less damaging to pocketbooks and reputation than the uptick in the number of people who will have problems. Presumably they've determined that the cost benefit of going with something else isn't favorable, they're sticking with the CP4 for now.

So you have some choices. Just go with what Ford says, and by the averages you'll still probably be fine. There have been some bad stories about Ford unreasonably denying CP4 failure warranties on some very questionable basis' like "the tech smelled something" and disregarding actual lab analysis of the fuel that showed it was only diesel, calling the person's bluff about going to court over it. But like anything else it's the bad stories that you hear about and there could be 1,000 honored warranties to every bad story.

Or you can decide that on this one you're not going to trust Ford and take your own actions to mitigate the risk. For my part, while I still like Ford a lot, this is an area where I believe they're willingly transferring the risk to owners so I don't really trust them to do us right on the warranty side, when they're doing us dirty on the equipment side. I use additives that add lubricity and have shown to bring the same fuel that tests in the 520-530 micron range down to the 350-400 range. This puts them well within spec for normal service life. In addition I'm spending some extra to put a diaper on the CP4 so if it defecates the cradle so to speak, the problem is contained at the pump and doesn't destroy $10,000 worth of equipment downstream. And that's really the kicker. Risk is measured by multiplying likelihood with impact. Even with low likelihood a high enough impact still comes out to a risk value high enough to act on. If cost of the might-happen failure weren't so high then I wouldn't willingly put myself out of the terms of the warranty. I don't usually bother with this kind of stuff, but this one is big enough that my own risk acceptance threshold is crossed. A different but similar comparison is buying lottery tickets, I don't ever buy them except every now and then the lump-sum minus tax payout divided by the odds ends up where every chance to play is worth more $ than the cost of the chance. Cross that threshold and I get involved.