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*** Cross-posted from the Performance board ***
(Scott, I thought this thread might elicit more response on this board, although it has been taken up on the Performance board too. Apologies if this is not acceptable).
Please see this thread on the Performance board for more context.
9000s with TCS have an electronically controlled throttle, i.e. "drive-by-wire". When this is working correctly, the action of the throttle cable (which is only there for use when the TCS system fails) lags behind the throttle. You would have to pull it quite a way, while leaving the pedal untouched, before it caught up and then started opening the throttle.
When you press the accelerator, you are operating a position sensor and the TCS system opens the throttle more. Hence the pedal works, but pulling the cable appears not to.
Another symptom of TCS limp-home mode is that the car will hardly idle, if at all. This is due to the fact that TCS controls idle via the electronic throttle. I don't think TCS cars have the idle control valve used on non-tcs cars. Therefore, when it fails, the throttle is only controlled by the backup cable. This has no influence until you press the pedal about 1/2-2/3 of the way down, then all your throttle control is at the bottom 1/2-1/3 of the pedal travel. It's not nice to drive like this. In addition, I believe you will only have base boost, although 10psi (0.7bar) seems a bit high for base boost. Do you still have your MBC connected? That would explain why the boost is a bit higher than the 0.45-0.48 bar (6.5-7psi) I would expect to see under base boost conditions (assuming a manual Aero - can't remember if it's manual or auto).
I'm not certain you have a TCS problem due to lack of a TCS warning light (which could be blown, of course), but many of the symptoms sound similar. TCS controls the throttle whether it is switched on or off (when off, it just doesn't perform traction control), and you can encounter limp-home mode in either position of the switch, simply as a safety measure - you don't want a faulty system controlling your throttle!
Again, if you still have an MBC connected, I would recommend removing it until you get the problem sorted out. The fewer variables you have to juggle, the better.
I know Scott doesn't like cross-posting, but I really feel that this thread may benefit more from the experience on the 9000 board, where you have also posted it. I'm therefore going to cross-post my reply in your thread on that board. Sorry if this is out of order, Scott.
posted by 62.253....
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