Hi guys
when im accelerating hard and take my foot off the throttle and press the clutch in to change gear the revs rise by 2/3k for a second before returning back to normal, it only seems to do this when accelerating in open loop.

Any ideas guys?


I've logged a WOT run at - WOT Datalogs - Windows Live

 

What year is your car m8?
Mine does this also and having researched this a lot it appears to be very common on new age scoobs.
It's a pain in the rear and up to now nobody has come up with an answer/cure

 

it is the 2001 WRX UK300

 

has anyone found anything out on this fault as its driving me wild. i have 2003 wrx.

 

Thought it was my cr@p gear changes, but I have also noticed it.
03 WRX

Steve

 

Is it not just the throttle sticking and staying open???

Happened to my '97 WRX and was just the throttle was a tad stiff.

 

same here id like to find out more as ive naticed my 02 wrx does the same

 

wow,this must be more common than i thought!!!i put a thread in just like this months ago and was told its nothing to worry about as its the engine management system or something i cant exactly remember word for word.it is annoying tho.mines a bug too!!!!!!

 

ive tried a few things , cleaning the throttle spring regreasing it and ajusting the cable a bit in case it was to tight . just have to get used to it i guess

 

i think its an electrical issue built into the ecu!

 

long shot, neutral position switch?

 

same problem here it is driving me mad I have been told it is the stepper motor on the throttle body got told to convert it to manual throttle cars mine is a 53 wrx. dont know how big of a job this would be if it can be done.

 

You may find its the actual butterfly valve in the throttle body itself,being a turbo it gets alot of dirt around it from the turbo gases,oily crap and it can get gunky,i took the intercooler off mine and held the throttle open via the valve at the side of the throttle body (engine off) and used various agents to clean it,wet wipes,turps etc and it does cure a problem like this,mine is a classic tho so maybe you do have an electrical reason but i found this cured my fault when i had this problem,worth a try

 

I think you'll find that its deliberate.....

Holding the 'throttle' open (OK keeping the IACV open on pre DBW cars) on liftoff softens the transition to engine braking (its called "throttle damping" or "dashpot"), the system can't predict you dipping the clutch to change gear, so you get the rpm hang, lots of modern cars do it.....it also helps protect the catalyst from the rich spike you get from sudden large reductions in airflow/manifold pressure and thus ensures the catalyst copes with the requirements to achieve the emisssions requirements to 100,000km as dictated by law.

Simon
Working for OEM's on EMS's since 1989

 

Revs hanging when clutch dipped and revs rising tho are 2 different things,OP says revs rise by 2-3k that aint normal !

 

It can be yes......I've not driven that exact model year with that ECU (have you?) which is what would be needed to determine 'normality', but have driven cars with that level of rpm rise.

Simon

 

same problem here 53 wrx revs rise around 200 - 300 rpm on gear change.

 

yeah my bros 53 plate does the same too... not that it bothers him norr does it me when i thrash "woops" i mean steadly drive it