1.0 Ecoboost P0299 Underboost

Hello

I recently bought a 2018 1.0 focus (mk3.5) that needed a clutch. After reading all of the horror stories I thought it was worthwhile to do the belts too and changed the other service bits not part of the belt swap.

First proper drive and I quickly found that the car was horribly slow. Logged a few channels in forscan which pointed to the check valve being broken on the vac pump, that’s replaced and now I have another issue.

I’m pretty sure the car is mapped as I’m seeing 35psi desired and actual boost pressure when under full load and the car really does go well.

What’s not so great is that in 6th uphill at moderate throttle al low rpms (I know this isn’t ideal but it’s a genuine use case on the motorway) the car will flag an under boost code. I’m lead to believe that underboost is triggered when the requested vs actual pressure doesn’t align within a set period of time (4psi max diff - 5 seconds)

The car is requesting 30 odd psi at 1500rpm which seems a bit excessive considering the low engine speed, map sensor pressure at this point is around 18psi. The turbo comes in strong at 2500rpm and request vs actual match until the redline

The above numbers aren’t corrected so you can take barometric pressure values off them so they make more sense ~14.5psi in my case.

I’ve checked the vac pump both for vacuum and gauze blockage, all good. Smoke tested all the vac/boost lines. And also actuated the wastegate manually by drawing vacuum by the boost solenoid.

Does anyone have a log of a 1.0 ecoboost in a gear above 2nd that’s from 1000-1500 rpm. Ideally logging rpm, desired boost pressure and actual boost pressure? I’m beginning to wonder if the tune is actually the issue, or maybe these cars can make high boost at low rpm?

Edited May 3May 3 by Jb154
Added info