2.0 gx wagon running problem

[conrod]

My 2005 gx wagon seems to rev high when you come to stop at a junction or if you travel along at normal speed [any speed] and dip clutch it will rise to 2000 revs and hold there until you change down again.

I have taken the car to a dealer to put on their machine and cannot find anything.any help on this would be grateful.

[The Don]

As it's a N/A you may need to clean the idle air control valve.  Vid below is for a N/A legacy but exactly the same

https://www.youtube.com/watch?v=bzNiEajOrSA

 

[ccrien]

Just when cold, or all the time?

they can often be like that when cold and as you say, when dipping the clutch just before changing down approaching a junction for example, for a couple of miles max, but should be  " normal" when warmed up.   

Sorry, dont have an answer but a few things to consider:

if aircon is on, try with it switched off?     The aircon on increases the idle speed slightly, 

is battery holding a decent charge, or top up with a charger and see if its any better?   And try with little electrical load ( no lights, rear screen etc), see if its any better? 

if its worse when cold, try getting it to 3-4000 rpm just briefly with a bit throttle and pulling in a low gear after going half a mile or so, might " switch off" this feature ( until next cold start up).      Also, See if you can drop the revs, if you blip the throttle while in neutral just before changing down.

Hopefully its the feature built in to help reduce emissions when the motor is cold, but if its also happening when the engine is hot, likely to be a sensor needs replacement, but determining which one is the hard part: exhaust sensor, temperature or somethng else in the fuel/ air system???

good luck.

 

 

Edited February 23, 2020 by ccrien

[conrod]

Thanks for coming back to me on this,

maindealer said they checked, cleaned everything they could think of even swapped the ecu over just in case something had been maped in. 

Dealer seamed to think its something between ecu and icv .maybe another sensor ???

do you think it might be the speed sensor that's on the gearbox???

[ccrien]

20 minutes ago, conrod said:

 

do you think it might be the speed sensor that's on the gearbox???

Very much doubt it, if the symptom is when youre stopped or with clutch depressed.

 Try Don's suggestion in case the dealer didnt do this?

[conrod]

Yes I cleaned the valve and throttle body aswell.

is their a wireing diagram of this part of the system so I can trace back from the icv.

[The Don]

Engine electrical.pdf

[conrod]

Thanks Don maybe I can trace the problem through the wiring.