Raptor thinks it's getting low octante fuel

[mvasilakis]

My 2018 Gen 2 with 45k miles keeps down tuning the engine and lowering boost because it thinks it's getting lower octane fuel. I've tried fuel from several gas stations, reset the ECU, and yet it's still happening.
Does anyone have any ideas where I can start to get this sorted? (My local dealerships aren't the most eager to find what's wrong with the truck unless it isn't moving.) I have several close friends who are mechanics but this is above their pay grade.
Any help would be appreciated.

 

[TwizzleStix]

Boost isn’t the target for power, so it is really irrelevant. What makes you think it is “down tuning”?

 

[mvasilakis]

For one it's reading estimated 88 octane on my cobb tuner. When I reset the ECU the truck is a different animal. After a couple days it starts dogging out. Boost wont go past 1/2 way and it feels like it's struggling. I also own a 2019 that's my wife's daily driver and that one doesn't have this issue even though it gets fed the same fuel.

 

[CigarPundit]

Calling @FordTechOne

Bad knock sensor?

 

[mvasilakis]

Maybe. I'm not getting a code but I suppose it's not outside the realm of possibility that the sensor is bad. I get a shit ton of wastegate rattle when I first start the truck but that goes away after it warms up. I don't think that could trigger the knock sensor though could it?

 

[CigarPundit]

I don't think so.

 

[FordTechOne]

For one it's reading estimated 88 octane on my cobb tuner. When I reset the ECU the truck is a different animal. After a couple days it starts dogging out. Boost wont go past 1/2 way and it feels like it's struggling. I also own a 2019 that's my wife's daily driver and that one doesn't have this issue even though it gets fed the same fuel.

Is it currently on the stock tune? If not, start there. Are there any other mods? Certain vibrations can read within the same frequency as knock, and the knock sensors will pick that up, causing the PCM to pull timing and boost. See if your COBB tuner has any parameters available to monitor.

 

[mvasilakis]

I've had this issue since I bought the truck. I didn't know that boost was supposed to max out till we bought and drove my wife's Raptor. I've never had a turbo charged vehicle before so I don't know much about turbos. When I put the tune in it started boosting all the way but only for about a day or two. That's when I realized something was off but I didn't know what. I reached out to Winfield to see if he's seen this sort of thing before but I figured I might have some luck in the forums with all the techs and tuners here someone might have seen this sort of thing before.

I was thinking about adding a bottle of octane boost. resetting the ECU and seeing if the Cobb handheld reads a higher octane or will it drop back down to 88.

 

[CigarPundit]

I very much doubt it's the gas, especially since your other Raptor drinks the same fuel. I'd listen to @FordTechOne

 

[mvasilakis]

Yea, There are some knock parameters. I'll load those and see if the sensors are picking something up.