Bradders59 Posted May 9, 2021 Report Share Posted May 9, 2021 I have noticed that when I press the clutch pedal and lift off the throttle to change gear the revs seem to jump a couple of hundred rpm for an instant before dropping. Never experienced this before. Anyone have an explanation ? Not overly bothered by it, just a bit puzzled. Quote Link to comment Share on other sites More sharing options...
Bradders59 Posted May 10, 2021 Author Report Share Posted May 10, 2021 I take it, it isnt a common occurrence then. 😄 Quote Link to comment Share on other sites More sharing options...
GmanB Posted May 10, 2021 Report Share Posted May 10, 2021 I have a tip box on my car, but did notice this when I had a 6 speed manual as a courtesy car. I put it down to the bite point on clutch being a little high on the pedal and that my throttle/clutch work wasn't great. Quote Link to comment Share on other sites More sharing options...
zadocbrown Posted May 10, 2021 Report Share Posted May 10, 2021 User error.... Quote Link to comment Share on other sites More sharing options...
BBB Posted May 10, 2021 Report Share Posted May 10, 2021 Is it the effect of the dual mass flywheel? Quote Link to comment Share on other sites More sharing options...
Bradders59 Posted May 10, 2021 Author Report Share Posted May 10, 2021 Could be. Ive never had a car with DMF before. It isnt user error. I have tried to make very careful deliberate gear changes to se if it changes anything, but it doesnt. Quote Link to comment Share on other sites More sharing options...
charlieboy2608 Posted May 10, 2021 Report Share Posted May 10, 2021 Throttle pedal sensor? Quote Link to comment Share on other sites More sharing options...
Bradders59 Posted May 10, 2021 Author Report Share Posted May 10, 2021 Possible I suppose. It isnt really a problem (yet), but I am a little curious about it. Will keep an eye on it and see if it gets worse. Quote Link to comment Share on other sites More sharing options...
Shazbot Posted May 12, 2021 Report Share Posted May 12, 2021 Mine does a sort of anti stall if you dip the clutch as I pull up to lights sometimes. Having changed my clutch and DMF when i first got the car i can say the DMF is a properly large mass so may be guilty. Quote Link to comment Share on other sites More sharing options...
femreg Posted May 13, 2021 Report Share Posted May 13, 2021 Do you have servo type throttle(until 1999) or ECU controlled throttle(2000 onwards)? If it is servo, worth to check if it works OK. No experience with this. For ECU controlled ones, I guess that there is no unintentional accelerator pedal press by carpet or any other object / faulty clutch pedal spring. If there is no extra piece, and acc. pedal couldn't travel to 0% pedal quick enough, that may be your issue. Side view for a reference: Additionally, I don't know all Bosch ECU software features for Boxster but this ECU may have Gear Shift Harmonization(GSH) feature. For functional safety, if the clutch switch is faulty then this feature can be disabled. At least scenario is that clutch switch misplaced and confuses timing of the GSH. Clutch switch, engine speed and vehicle speed used for gear detection and shifting events, but back then these features were not sophisticated as today. Hard to guess. In these days, I have to drive different cars but as I remember, the engine starts only if you are pressing the clutch pedal. If your engine starts without pressing clutch pedal, you may have faulty clutch switch. Next time, during my drive, I will test whether there is a GSH or not. Quote Link to comment Share on other sites More sharing options...
Bradders59 Posted May 13, 2021 Author Report Share Posted May 13, 2021 Its a 2000 car so I would guess ECU controlled, although I havent looked yet. I shall put it on the "to do list", which so far, doesnt seem to get any shorter. Quote Link to comment Share on other sites More sharing options...
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