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.
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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.
But if there is crap to collect on filter screen on pump intake, can cause pump to overheat.
Always been a thing that you shouldn’t run a tank that low as it can then pick up ‘crap’ from the bottom of the tank but no idea how true this is. There should be a filter before your high pressure pump anyway which should catch any ‘crap’
I have been running my tanks dry for 17 years. Tanks usually have issues with those who keep the tank topped off or half way because the more fuel in the tank the more water the ethanol attracts, the more water in the tank means more rust & bad gas & you run into issues. Running it dry allows you to use ip all the ethanol & water ij the tank in smaller amounts vs allowing it to accumulate. Now if you use ethanol free gas you are good to go, but run it til the light comes on.
This is so wrong
unfortunately yes. vehicles with direct injection use a low pressure pump in the tank and of course the high pressure pump near the fuel injectors. when you run the tank low, the low pressure pump has to work harder to supply consistent fuel pressure to the high pressure pump, meaning it is working harder as well. however because the high pressure pumps run at over 1000 psi, straining them due to low fuel pressure is fatal much more often than a low pressure pump. it’s also more fatal for high pressure pumps as they somewhat rely on the fuel to lubricate the pump, much more so in diesel vehicles. so just make sure not to run it too low too often and all will be well
The high pressure fuel pump on your vehicle is cam driven based on my research. I do not believe low fuel in the tank is related. That type of pump had high failure rates on several Volkswagen models. The solution was to inspect the pump every 40,000 miles and replace the cam follower.
Very unusual for a skyactiv motor to have major issues like this let alone a high pressure fuel pump. You need to break that stupid habit of running your car that low seriously. You are not doing your other low pressure pump any favours either….
its just as easy to keep the top half of the tank full as the bottom half.