I'm at a bit of a loss here, so I'm reaching out to the community to see if anyone has ever seen similar behavior. If you search for "N54 throttle response" you will get a ton of people complaining about it, but I've yet to see anyone with a similar issue as mine.
The problem that I'm trying to solve is a massive throttle lag that makes the car feel extremely slow to react to accelerator pedal input. The following data shows that the car CAN, when software/sensors allow, react blazingly fast to accelerator pedal position. But it doesn't.
Car is E82 135i, 2007, MT, with MSD80 running I8A0S (not sure what the native version was).
No load to the engine, this behavior is logged with the car coasting on neutral and the only difference is clutch pedal either being up or down. This behavior does not exhibit itself when the car is at standstill. throttle response is immediate at standstill regardless of clutch pedal position.
The delayed throttle response is present always when driving the car, the only way to get the throttle to respond quickly is to press down the clutch pedal and then work the accelerator pedal. Therefore, as this is MT, rev-matching downshifts accurately is possible.
So, the following behavior can and has been logged:
clutch pedal pressed, gear neutral
- gear reads correctly in logs
- throttle response with accelerator pedal press is immediate
- rpms respond immediately
- boost target is raised
- wdgc can react upwards, up to 100
clutch pedal raised, gear neutral
- gear reads incorrectly in logs
- throttle response with accelerator pedal press is delayed
- rpms respond sluggishly
- boost target is 0
- wdgc reacts downwards or minimally upwards
And here is a log of the behavior:
https://datazap.me/u/works/throttle-...og=0&data=2-25
First three rev ups are with clutch pedal raised, the next three clutch pedal pressed. You can clearly see that with a similar accelerator pedal position the throttle opens either super fast and RPM's climb quick which leads to me releasing the accelerator pedal, or when the clutch pedal is raised the throttle opens slowly + only a little and the RPMs raise slower which leads me to keep the accelerator pedal pressed for longer.
I've replaced both MAP sensors and the throttle body assembly. The car is stage 1 turbo +fbo +flexfuel. Clutch delay valve has been deleted and the clutch is from 550i, not sure if either of those are somehow involved in this. To me this looks like a sensor or software issue as the throttle response can be amazingly fast when the clutch is disengaged and pedal is down or the car is stationary.
Do note that resetting adaptations does nothing to alleviate this. I've tried several different software versions from two tuners and the problem persists. So that puts more weight on this being a sensor issue. But which one?
I sincerely hope that some of you brainy people can shed some light on this and come up with solutions for me to try out.