I have a 2019 3.5 Ecoboost. I was pulling a camping trailer through the mountains and it started to over heat really quickly. The computer decreased the truck’s power. Later I realized that air shudders in front of the radiator were shut and not opening and that’s why it was over heating. I manually opened them and unplugged the actuator motor so they can’t close, I’ll deal with that problem at a later time but for now the truck is not over heating. During this time that it was over heating I all of the sudden heard a air whooshing sound when the truck was producing boost. It sounded like it was coming from in front of the dash but With the window down I could also hear it coming from the engine compartment. It got louder with more boost. A couple days later when leaving the camping area and pulling up a hill, building boost for quite a few seconds, still hearing the air whooshing, all of the sudden the air whooshing stopped, i lost tons of power, no more boost at all and the yellow wrench, see manual light came on. Later the check engine light came on, the code was P0299 turbo underboost. I’m assuming the computer opened the wastegates because it sensed the underboost and that’s why I lost power. Shutting the truck off and clearing the code brings back power, boost and the air sound but pulling up a hill and building boost for more a few seconds causes the problem again, no boost, no power and the sound is gone. I’ve replaced the blow off valve that sits on the cold side of the intercooler, thinking maybe it was leaking and creating that sound. So I’m assuming the sound is a boost leak somewhere. I’ve checked all the connections and hoses, everything seems good. What I’ve never heard of or read on any forum is the truck losing all boost and power when code P0299 comes up and the air sound going away I think it’s got to be the truck’s computer keeping the waste gates open. Is this a waste gate problem, turbo problem? I haven’t check them yet, besides just visual inspection.
the wastegates opening is just as you think it is.. the computer sensed the underboost and opened them up to protect the engine.
I have experienced the same thing as you, except without the overheating. What temps were you seeing? Trans or Engine temp?
I’m not stock.. so our issues are not likley the same. However, when I tow, I do not let the truck shift. I put it in manual mode and do the shifting myself. The truck wants to keep RPM low and build boost when it needs extra power, Im ok letting the Rpm stay high ( I keep above 2k and let it get up to 4500 when climbing)
As the truck gets warmer, there are multiple stages to it de-rating itself, before it is officially overheated and nags you with a wrench symbol and goes into full on limp mode.
When you heard this whooshing sound, was it when temps were pretty hot, but prior to getting the actual wrench symbol on the dash?
If so my guess is the whooshing is just the waste gates opening to let more boost bypass the engine intake >> keeping boost, therefore heat down. Continuing through these conditions might have then led to full on overheat.
My thinking is that I have a boost leak somewhere. That’s what I’m working on finding. The sound is heard with normal driving when building boost. The concern is that when I’m towing uphill, hearing the sound and building a lot of boost for quite a few seconds then the sounds quits, I lose tons of power, and I get the under boost code. FYI the truck does not over heat anymore since I have the air shudders open.
Ok makes sense, may well be an old fashioned boost leak.
Just be sure truck has no codes stores on it before you go looking. Otherwise for as long as it is running in limp mode, it’ll be diverting air around the turbos…. Whooshing.
Also, in addition to checking the couplings, some folks have found cracking where various sensors plug into the intake tubing.
I just found a break in the connection where the hose coming from the BOV hooks into the air intake tube. Could that be causing the whooshing sound and boost leak and under boost code, even though it’s on the intake side, before the turbo, before they air is pressurized?
I just found a break in the connection where the hose coming from the BOV hooks into the air intake tube. Could that be causing the whooshing sound and boost leak and under boost code, even though it’s on the intake side, before the turbo, before they air is pressurized?
That can absolutely cause the whoosh. The wastegates, no whoosh. That connector from the bov to the intake does hit max boost pressure when the bov actuates, it recirculates the boost back into the intake with a pressure spike. A crack in that hose essentially gave you a vent to atmosphere bov. Loud whoosh. You should only hear it when you let off the throttle, and only briefly, if the bov is in working order tho. What it wont do is cause an underboost code, you could completely disconnect it and everything would work fine, but with a whoosh. Underboost code would typically happen when the cold side intercooler to throttle body pipe has a leak, thats been my experience, the 2 turbos can generally compensate a bit for eachother if it's a smaller leak only on one side, the 2 hot side connections at the intercooler could also be suspect, since they are right together you are more likely to lose the boost instead of it going through the intercooler, path of least resistance and what not.
I would respectfully disagree with killa in the above comment, the air reading is calculated using the manifold air pressure and temperature, both grabbed withing the intake manifold, because the 3.5 doesn't use a mass airflow sensor, it is not actually metering the air, it makes a calculation based on its reading inside the intake manifold.
Another issue I dealt with in the not so distant past, make sure the ait2 sensor, On the pipe before the throttle body, is connected properly, they can be deceitful when they lock in and dump your boost...with a whoosh, ha. It's also kind of on the bottom/side and easy to miss if you are focused on intake pipe connections
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