I drive a 2015 mazda 3 with only 85k miles. I treat it incredibly well and follow the maintenance interval in the manual religiously. The only thing Im bad about is I would literally run the gas tank to 0 miles range every single time because I would still only be putting 10-11 gallons in to the 13.2 gallon tank to fill it up so I knew it wasn’t truly empty.
Well a few weeks ago my high pressure fuel pump failed. Ended up having it replaced by mazda because I wanted the oem part. $750 part + $750 labor, ouch. Did I cause this by running my tank so low every time or is it just a coincidence? These vehicles are known to be rather reliable so to have a repair like this at 85k sucks. I now fill up at a quarter tank but I am still curious if this is my fault or if I just got unlucky.
Probably not, the in-tank low pressure fuel pump feeds the high pressure pump via fuel lines. The reason people say it’s hard on the fuel pump to run the tank low is that the pump won’t be fully surrounded by the fuel in the tank and will run hotter/harder. This shouldn’t impact the fuel supply to the HPFP, but it’s still not an ideal thing to do. That said, if you’re regularly running to the point that the car dies, I could see that causing an issue.