VY not backing off between gear change
Hi there. Would like to find someone who can tell me how to disable the "Slow return to idle after the clutch is depressed" feature on my Manual VY. I have been told it was required on previous model to prevent stalling. However it is realy spoiling the driveability of the car. Ie engine revs do not back off between gear changes. I think the software would need to be altered or if used for nothing else maybe the clutch switch could be disabled. I cant be the onle one that hates this. Hope someone can help Regards Mike.
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Why hasnt anyone replied?
Turbo L98 FTW
You sure it exists? My revs drop quite quickly.
I'll have a word to our inhouse online mechanics. 23 minutes is absolutely unacceptable.Originally Posted by Mike54
The fact that you still don't have an answer is beyond me. I'd put something in writing to the administrators or Holden themselves.
My old vy s pac ute used to do that, i never figured out why, hope someone can elighten us both.
Definatly exists. quite obvious. makes you sound like a lerner driver. I removed the switch last night and my wife drove to town today. She said no change but now cruse control doesnt work. Then I realised I had left the switch in the operated or clutch down position. ********. I will go and tape the switch and try again. It will mean the cruse wont disengage but I will know Im on the tight track. Mike
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Never heard of this, sounds more like a buggered clutch to me. Anyone who stalls a Commodore needs a talking to, the flywheels on these things weigh about as much as Kim. Beasely
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VZ SS Glad some one else has had this prob. The service manager told me it was a known prob but no one else seems to know any thing about it. The thing just doesnt back off when you lift your foot off the accelerator and depress the clutch. RPM decayes over about 2 or 3 seconds. Most noticable when you get stuck into it. I origionaly thought it may be a anti polution measure ie. preventing running rich on the over run. I just cant stand the thought of taking it to the dealer to have some 12year old tell me it,s ok they all do that. It makes me hate the car.
L plater :(
i hav it from 3 to 4th in my ute thats it
I know what u mean mate, pushing the clutch in you expect the revs to go straight down, but they just hover there, bloody annoying!! I took it to my friendly holden dealer, went for a drive with them in the ute; they said nothing was out of the norm!! Hope Someone knows bout it.
i have this problem in my VZ V6 ute, 6 speed manual.
But only when the motor is cold. once the temp is halfway on the guage, the revs drop instantaneously
"And i gave that man directions, even though i didn't even know the way; because thats the kinda guy i am today"
i was thinking about this and are you talking about the alloytec/ newer v8's and the Fly by wire throttle??? if so yes you can get the computer mapped so that its more responsive to the actual pedal control, i found it really gay driving an vz ute lol.
Throttle by wire technology sux.
Driving a POS toyota yaris... and the pedal to actual throttle response was out by at least 1 second... being a rental i by-passed this by foot to floor acceloratrix and side step clutch to get going in a hurryp
yeh i know what mean,my gts coupe does this also and as your letting the clutch out the revs just dissappair making you look it a fool bunny hopping down the street!!! good to see it must a common prob...
The reason it does that is for emission control,it allows extra air into the cylinders while decelerating to prevent a temporary rich mixture.If the throttle were to just snap shut and the IAC (idle air control) valve to do the same,there would be a normal amount of fuel in the manifold,with a less than normal amount of air (for that engine RPM), so you would get a rich mixture.
Hope this makes sense to everyone,but that's exactly why it does it.
No this is not correct, on quick throttle closing you will enter decel fuel cut, so you will have no fuel going into the engine. The problem happening with the vehicle is caused by the ECU controlling the IAC motor with the amount of steps that have been programmed into the tune.
On decel the idle speed control motor wont close the IAC port as the engine will stall.
It might be that the base throttle stop is either to low or to high and the ecu is compensating for this.
Ok,so if what you're saying is true regarding decel fuel cut,how can the revs increase?
No fuel equals less RPM than some fuel don't you agree?
They don't go to decel fuel cut the instant you close the throttle,connect your scan tool and go for a drive and see.
The IAC valve closing won't stall the engine because it still has the "base idle" setting,that is made with the IAC in the fully closed position.Maybe if the engine is cold it might.
I wasn't saying that when you closed the throttle that the IAC closes,if you check what I wrote you will see that I said "IF".
If you remember back to the days of carburettors,the later ones were fitted with a dashpot that slowed down the closing of the throttle plate,this was fitted for emission control reasons,as well as driveability.This is the same thing only it's done electronically.
If you read the OP first post he is saying that his problem is a "Slow return to idle after the clutch is depressed" if it did go into decel cut mode as you imply,it would stall.
Last edited by whitey66; 11-02-2010 at 11:36 PM. Reason: Added info
If there isnt enough base idle air going through, the engine is relying on the IAC to control Idle, if the IAC motor is compensating for this, the IAC motor will work at higher steps, the more IAC steps, the more air into the engine.
When backing the throttle of, manifold vacuum going up, and decel fuel cut gets engaged. If the IAC steps are to high, its like a massive vacuum leak and air flow will see show to high on the Maf sensor, so decel fuel cut wont be enabled.
No fuel into an engine wont make the rpm increase, however it will still slowly decrease.
Alot of manufactors stopped the idea of the dashpot, once catalitic converters were released.
So what your saying in all this is, Holdens released 100,000 manual cars 99% of the cars on the road dont suffer from this problem, and 1% have the problem, so how can this be an emission control.
What about larger cube engines eg LS1 series cars, why dont they have the same problem, after all they do have more emissions.
Personally what i would be doing, is clean the throttlebody, check and reset base idle air, reset fuel trims, and retry the car.
They all do it,only about 1% of people complain about it obviously.
When the VYs were first released I had 3 or more cases with Holden Technical Assistance Service (TAS).Their engineers advised that this was normal and for emission control,but maybe you know more than the guys that built them.
LS1 engine management was far superior than what the VY V6s were running,it could be programmed better to have more control of this problem.
The way it was done on the VY V6s was a stop-gap measure to comply with emission standards till the new engine was released imho.
Regarding the deletion of the dashpot on models with catalytic convertors,can you be more specific on what models did this??
The reason most of them deleted the dashpot with catalytic convertors was because they mostly had fuel injection
They all do it,only about 1% of people complain about it obviously.
When the VYs were first released I had 3 or more cases with Holden Technical Assistance Service (TAS).Their engineers advised that this was normal and for emission control,but maybe you know more than the guys that built them.
LS1 engine management was far superior than what the VY V6s were running,it could be programmed better to have more control of this problem.
The way it was done on the VY V6s was a stop-gap measure to comply with emission standards till the new engine was released imho.
Regarding the deletion of the dashpot on models with catalytic convertors,can you be more specific on what models did this??
The reason most of them deleted the dashpot with catalytic convertors was because they mostly had fuel injection
They dont all do it mate, i drove my mates identical ute after i noticed mine playing up, and his drove normal, with the revs dropping off like they should.
I thought it had something to do with the oem dual mass flywheel Holden fit.
They all do it,only about 1% of people complain about it obviously.
When the VYs were first released I had 3 or more cases with Holden Technical Assistance Service (TAS).Their engineers advised that this was normal and for emission control,but maybe you know more than the guys that built them.
LS1 engine management was far superior than what the VY V6s were running,it could be programmed better to have more control of this problem.
The way it was done on the VY V6s was a stop-gap measure to comply with emission standards till the new engine was released imho.
Regarding the deletion of the dashpot on models with catalytic convertors,can you be more specific on what models did this??
The reason most of them deleted the dashpot with catalytic convertors was because they mostly had fuel injection
So if all of them do it, why am i not agreeing with you on this one, as only one manual VY that ive driven has done it, i dont drive 100's of V6's but ive driven my fair share in my time.
Years ago i had to actually sort out a problem that had come from a Holden Workshop here in Adelaide in regards to a No start situation, with a VR V6 im talking years ago now, with all the technical support they had, why was the job given to another automotive workshop????? And its not just Holden dealerships, we use to look after Ford dealerships which were worse at diagnosing running faults. Nissan Dealerships would have been the most advanced workshops back then, and even then they didnt do EFI diagnosis.
When i was an apprentice all i was known to do was do call out EFI diagnosis for other workshops, and that was my position throughout my apprenticeship was EFI diagnosis, ive been to Bosch in Melbourne many times doing advanced coarses, in my time ive seen some weird problems, ive seen stereo installs cut vehicles out intermitantly. Ive seen guys replace parts due to a fault code that had nothing to do with the part at fault.
I remember i had a diary which i use to have all my symptons written down, and what the fault i had found, it was my so called bible, i actually showed a Bosch engineer in Melbourne, who actually read every page and photocopied the entire book, and he was absolutly dumb founded with the problems that i had written down, he said alot of these problems id probably never see again in my life time and guess what, he was correct.....
As a tuner i can tell you there are plenty of calibration files throughout all the ranges from the V6, some cars will lock the convertor earlier or later than others, some hold cold start longer than others, some have firmer shift points than others, not all cars of that model are the same.
Catalitic convertors were fitted on vehicle's that ran unleaded fuels.....as leaded fuel will damage catalitic convertors. Fuel injection was released back in the 50's and holdens didnt release injection till the VK era. With the Bosch engine management system.
Alot of the EFI running faults with cars, are all back to basic faults. Fuel, ignition & base idle air......
Last edited by enhancedss; 13-02-2010 at 01:42 AM.
Hi guys.
Sadly Wife reports still same with clutch switch taped in the pedal up position. I have always thought the problem was something to do with an antipolution measure like someone said I rember the old Carby days of delaying the throtle closure. However i had thought this would not be necessary with injection. How do I fix? Can it be remaped? Should I try to borrow some ones ECU? Are there any sensors that may cause fault? Great to see some real help out there. Regards Mike.
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Run a scna tool over it, if there's no problems (no sensors giving false data or errors) then tune it :P My money is on the tune.
Hi guys.
Think I may have fixed it. I think cleaning the throttle body (In particular the Valve mechanism and stepper motor that looks as though it controls the air mixture at idle?) It was pretty gumed up.
I was suprised just how dirty and gummy the inlet manafold was after the butterfly, I guess from the exhaust recirculation.
Are they all like this? I also found something interesting. The engine idle speed is different when the vehicle is moving even at very low speed one can see the RPM change ( About 1K when roling and drops to 750 when stopped). I would like someone else to confirm this. Also can anyone tell me how to Tune this engine, In particular the small plastic throttle stop screw as the idle speed is I think controlled by the formentioned stepper/Valve... I would love to be able to get into the programming does anyone have the software?
Quote ::Personally what i would be doing, is clean the throttlebody, check and reset base idle air, reset fuel trims, and retry the car.
Enhancedss. I think you are on the money. But can you please tell me how to reset base idle and reset fuel trims.
Will go for a drive and report back if it is now OK.
Regards Mike.
Last edited by Mike54; 03-03-2010 at 03:42 PM. Reason: Reread previous info.
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