F150 Ecoboost Forum banner
1 - 3 of 3 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
Hey all!

So glad there are these forums out there to tap in to everyone's knowledge!

I just purchased a 2011 F150 Ecoboost with 73K, metallic black, 3.73 max tow package completely stock and in overall great shape! I was very impressed by how well the exterior and interior were taken care of which helped my confidence in buying it. I am new to turbo engines and direct injection and hope to learn more about them. My main question today is about the turbo and what is normal for boost. As i've had the truck for a few months now I became curious about normal mpg's of these trucks. After searching through a ton of forums, it seems a lot of trucks can safely get 18+ on the freeway and easily 15 in town (to be conservative, I'm sure many of you are getting better than this). But my average in town stays around 11 or 12, and if i cruise on the freeway at 75 i get about 14.5-15. I also seem to experience hesitation when i step on it, close to 2 seconds before the tranny downshifts and it hits the power. Also on 2 occasions i've stepped on it to cross a busy road or intersection and the power isnt there for what seems like forever, and then it all hits and once causing driving hazards IMO. This led me to buy an aeroforce interceptor gauge to help me monitor my boost psi and other data.

This is what i've gathered so far. The highest boost i've seen when i roll into the boost and then step on it is 12psi, it doesnt hold it there for more than a second but i see the number display. Also, i understand that a negative number indicates vacuum. If i set the cruise control on the freeway at 75mph, my boost gauge seems to be steady anwhere from -4 and sometimes gets close to 0 if going up a small hill. If going up a decent hill it will go into boost (with the positive numbers) and stay around 1-3 psi. I went up the canyon so i could get a road with a really steep grade and the boost would hold at 7psi doing 65mph. My concern is that it stays in vacuum too much and isnt giving the engine boost at a steady throttle during normal driving. It seems to me that it would be normal to be going 75mph and for the engine to be recieving boost, i would think like 6 or 7 psi, since i understand that max boost on these on a stock truck is around 14psi (some guys get way more with a tuner).

I've already replaced all the plugs and checked to make sure they were gapped properly, and the computer hasnt thrown any codes. I really dont want to take it to the dealership without having an idea of something that might be wrong. I still want them to flash my PCM to the latest and greatest "update" to make sure the tranny is shifting right (I think the hesitation sometimes if i need to speed up fast is the computer trying to figure out what gear to pick and then finally going wot). I've also read these horror stories about timing chain stretch but truck hasnt thrown any codes. Might have Ford just check anyways to see how many degrees it is. As i understand it, the tsb on this is 5 degrees or less its ok (for a little longer) and 6+ and you need a new chain, tensioner, guides, cam phasers, cam bolts, etc which sounds really expensive.

So i guess my question is, do you guys think this boost psi sounds normal to you? Like i said im not familiar with boost and when its normal to be boosting and when it should dump boost and so on. Also something i noticed thats weird to me, and maybe not weird. Is if i am a at a dead stop and stomp on it, the higher the RPM's i go in a gear, the lower the boost psi will be, when the tranny shifts up to the next gear, the boost will be immediately back to about 10psi, and drop again as the RPM's climb to the next gear and so on. If the turbo is powered by exhaust, shouldnt i be getting more psi in a higher RPM? Or is this normal? Also at at slight throttle it sounds like its just dumping boost, its a hiss or whistle like the air is just whooshing under the hood.

Sorry for the information overload guys, just wanting to pick some people's brains that know these trucks and have maybe experienced similar problems. Any info or advice would be greatly appreciated and if i asked or said something dumb then feel free to poke fun at me, i do it to myself all the time!
I'm hoping when i get the truck running %100, my research will be more towards leveling kits, tire sizes, rims, steps, downpipes, etc.
Thanks again!
 

·
Premium Member
Joined
·
3,138 Posts
Welcome! Everything looks normal to me, but the mpg maybe alittle on the low side, but not by much from the average. Got pics?
 
1 - 3 of 3 Posts
Top