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Toyota Corolla 1.4 4ZZ-E52 2004 - RPM flair on gear change - Unresolved #

Posted by Christopher Taylor on September 11, 2013, 1:28 pm

Year of Manufacture *: 2004
Engine Size and Code *: 1.4 4ZZ-E52
( Optional ) Scanner Used: Bosch KTS

I am looking for some help with a customers Corolla. He complains of one thing. The engine does not slow down when you release the throttle pedal between gearchanges. In fact the engine RPM increases slightly before slowwing. Its irritating and I can understand why he is not satisfied with it.
The control of the idle speed otherwise seems perfect. I can find no fault with the engine condition, sensors or emissions. No air leaks detectable and I can not see a clutch switch fitted. The throttle potentiometer looks good on my scope. I was begining to consider wether this could be a software issue and would benefit from a reflash at Toyota. Unfortunatly I can not get past reception localy. Has anyone experienced similar problems?
Thanks very much.

Re: Toyota Corolla - RPM flair on gearchange.

Posted by Chris Angus <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5111' width='330' height='300' border=0 style='border:none;'> on September 11, 2013, 2:43 pm, in reply to "Toyota Corolla - RPM flair on gearchange."

Have you checked the throttle butterfly is fully closing and the throttle potentiometer is low enough to activate idle and fuel cut control.

Is there any live date for throttle position, eg idle/part/full?

What is the throttle pot voltage at closed throttle?

Chris

Re: Toyota Corolla - RPM flair on gearchange.

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on September 11, 2013, 9:41 pm, in reply to "Re: Toyota Corolla - RPM flair on gearchange."
Mark Carter

>>> I was begining to consider wether this could be a software issue and would benefit from a reflash at Toyota.<<<

If its been good from new until now I doubt a software update will be the answer.

Have you driven the vehicle?

How long has the current owner had the vehicle?

What's the work history telling you?

Mark

Modern cars, Its all wizardry and witchcraft

Re: Toyota Corolla - RPM flair on gearchange.

Posted by Christopher Taylor <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5137' width='330' height='300' border=0 style='border:none;'> on September 12, 2013, 5:39 pm, in reply to "Toyota Corolla - RPM flair on gearchange."
Christopher Taylor

This system uses a throttle cable to operate the butterfly. The throttle butterfly looks to open and close ok. The voltage from the potentiometer is within the spec listed on Bosch ESi at 0.3 - 1.0 v. I tried adjusting it and roadtesting but fault remains.
The customer has owned the car for a year. It has full service history and I can see no previous repair work that is relevant. I have a nagging feeling that all 1.4 Corollas of this design are the same as this car and there is no fault. I do not see many Toyotas due to there high reliability. The idle speed seems to be controlled ok and the fault is only aparent when driving. I would not be happy with it. Was partly hoping a AT member has experience of this specific vehicle to say I do have a fault or they are all a bit like that.

Re: Toyota Corolla - RPM flair on gearchange.

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on September 12, 2013, 6:03 pm, in reply to "Re: Toyota Corolla - RPM flair on gearchange."
Mark Carter

Thats fair enough, what does it do if you dip the clutch whilst rolling ? and if it is hanging does it return to nornal when the vehicle comes to rest?

Mark

Modern cars, Its all wizardry and witchcraft

Re: Toyota Corolla - RPM flair on gearchange.

Posted by Christopher Taylor <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5137' width='330' height='300' border=0 style='border:none;'> on September 13, 2013, 9:23 am, in reply to "Re: Toyota Corolla - RPM flair on gearchange."
Christopher Taylor

Dipping the cluch whilst rolling does not seem to effect it. The revs drop as you come to rest but the the time it takes to stop is about the same as the "hanging time". Seems that its only for a second or three but that becomes annoying between gearchanges. Sometimes you sense the revs have increased as you release the throttle pedal. Its strange.

Re: Toyota Corolla - RPM flair on gearchange.

Posted by Jim Power <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3202' width='330' height='300' border=0 style='border:none;'> on September 14, 2013, 4:36 pm, in reply to "Re: Toyota Corolla - RPM flair on gearchange."
James Power

Hi Christopher

I cant offer you any solutions I'm afraid but have noticed this on many Toyota's although have never had anyone complain about it. Has the car been like this since the present owner purchased it?

I am almost convinced it is by design rather than a fault. If you google it you will find many complaints about it but little by way of a solution.

One interesting theory I found was that it is to prevent an emissions blip by not allowing the throttle closing off too quickly.

It might be interesting to scope the throttle response time closing, when the car is stationary and while driving and compare.

Jim

jim power

Re: Toyota Corolla - RPM flair on gearchange.

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on September 16, 2013, 4:57 pm, in reply to "Re: Toyota Corolla - RPM flair on gearchange."

If there intentionally it may well be for emission control by reducing trailing throttle issues. But with out a test drive it is difficult to know.

Mark

Modern cars, Its all wizardry and witchcraft

Re: Toyota Corolla - RPM flair on gearchange.

Posted by Dave Hill <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2783' width='330' height='300' border=0 style='border:none;'> on September 16, 2013, 11:22 pm, in reply to "Re: Toyota Corolla - RPM flair on gearchange."

Mark Carter wrote....

"">>> I was begining to consider wether this could be a software issue and would benefit from a reflash at Toyota.<<<

If its been good from new until now I doubt a software update will be the answer.

Have you driven the vehicle?

How long has the current owner had the vehicle?

What's the work history telling you?

Mark ""

That is an interesting comment Mark & one that surprises me.

Although I have the same logical question nagging in my mind.... "It has been fine for years on it's original software, I can't see why a reflash should fix this fault???" I have however witnessed many examples where vehicles have benefited enormously from a PCM software update.

Unless I am dealing with an obvious mechanical, fueling or ignition type running fault & I am looking at a more subtle "management" type problem, then software is probably the one area that I will look into very early on these days. I have overlooked this in the past & kicked myself for doing so.

Without wishing to sound "elitist" I have often wondered how other repairers would have dealt with a job that I have fixed 100% by a simple update?? I don't have the capability to perform updates on every (or even most) marques, but I factor this into my approach. If I am limited in this area, then I might step back from a job & refer it to someone who is more able to perform the necessary steps.

I should also add that, it is not just software updates that are a critical part of the modern diagnostic & repair process, but also the capability to perform the multitude of resets & re learn procedures that are often missing on anything other than the dealer tool. I am sure that many technicians will have experienced jobs that have been 90% fixed by another repairer, only for them to fall at the final hurdle. That hurdle being the function missing from their scan tool.

In my opinion, the vehicle manufacturers are winning the battle I am afraid

More food for thought!

Unresolved #

Posted by Christopher Taylor on November 29, 2013, 2:47 pm, in reply to "Toyota Corolla 1.4 4ZZ-E52 2004 - RPM flair on gear change #"
Edited by board administrator December 2, 2013, 6:27 pm

This post needs concluding after being open for quite a while. My customer has after some explanation and attention decided to live with the Toyota and its quirky rpm control. I found no faults with the car or anyway to improve it.
In the meantime I have not had and other models in the workshop as a comparison. I do not know if the Toyota dealer can improve the software.
A very useful topic board in the future could help members out dealing specificaly with reflash cures.
I know this would be difficult but imagine the time it could save if we had somewhere to look listing the software updates that were known to cure specific driveabilty issues. It could never be an exhaustive list of course but it could help. Especialy as a group our knowlege overlaps, as we are all stronger on some manafacturers and weaker on others.
Thanks for your replies.

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