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Old 14th December 2012, 11:19   #91
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Default Re: RPM shoots up when changing gears

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Originally Posted by n.devdath View Post
Rajesh, before you start getting tense, let us start with the basics. Since the incident did not happen again, are you 100% sure that it was not the floor mat fouling with the accelerator pedal?
............
Remove the mat and check the pedal mount/hinge for obstructions. Let us take up other things thereafter.
Quote:
Originally Posted by Guna View Post
In 'drive by wire' the accelerator pedal and the throttle mechanism are not linked by a cable but rather through an electronic system. Many modern cars have it these days.
Thanks Devdath. I did think of that but I discounted it immediately because I've taken out all my mats due to a water leakage issue. The mat that is there is the small plastic mat from the rear passenger area and it is a short on and does not reach anywhere near the pedals. I'll check the mounts as you said but the problem resolved spontaneously after 15 minutes of switching the engine off.

Thanks Guna, I'll just check the manual now
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Old 14th December 2012, 11:30   #92
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Default Re: Ford Fiesta rev low response

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Originally Posted by myshanks View Post
Friends,

Sometime I have a peculiar problem in my Ford Fiesta 1.4 Duratorq.

When i rev up in 2 gear and 3 gear and push my clutch to change to higher gear, the rpm does not come down immediately and takes time to come down. It is awkward when I push the clutch and the engine is still at higher RPM.

I am sure I have articulated my problem well.

shanks
I have the same problem in my optra.But after browsing I found that many cars have this characteristic or should I say issue! Its called "rev hang".
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Old 14th December 2012, 12:29   #93
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Default Re: RPM shoots up when changing gears

verito does have drive by wire, and yes, the same RPM shoot up happened with me also only to find the floor mat playing fool with the accelerator pedal. Set that up correctly and no problems so far.
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Old 14th December 2012, 13:02   #94
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Default Re: RPM shoots up when changing gears

i had the same issue while i drove to bangy in my friend's C class, but then i kinda adjusted my driving style, depressed the clutch a little late when i wanted to shift gears, but this rev hold kinda helped in smoother gear changes, like passengers never feel the shift jerks. this rev holding mechanism or system i thought would increase braking distances but to my surprise it did'nt i noticed that everytime i lift off the accelerator and touch the brake pedal the revs drop creating engine braking, even if i did them instantly.
but like some of our friends who get their floor mats to operate the accelerator for them beware (just kidding),
Ok on a serious note: this rev shooting issue due to the floor mats being improperly laid could get you panicky during emergency braking.
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Old 14th December 2012, 14:12   #95
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Default Re: RPM shoots up when changing gears

Yes I face this on my Duster, when I press my clutch sometimes. Instead of slowing down it just shoots ahead. Is this what you are talking about, Woodcrawler?

I think it is normal for Duster. You need to adjust your driving style for this car a little.

This is not consistent though. Especially more likely to be seen when you press the clutch immediately after you release your accelerator.

Last edited by acroback : 14th December 2012 at 14:15.
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Old 14th December 2012, 14:19   #96
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Default Re: RPM shoots up when changing gears

Momentary rev hang is an ECU condition set up by the car manufacturers to enable complete combustion on sudden throttle lift off. It is an emmissions requirement.

If the rev hang is prolonged, it means either:
1. You have a small vaccum leak.
2. Your throttle cable (if present) need adjustment.
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Old 14th December 2012, 15:37   #97
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Default Re: Renault Duster: Automatic engine racing

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Originally Posted by woodcrawler View Post
Guna, You have me stumped about the 'fly by wire' but there certainly were no lights flashing on the instrument cluster. I know they have the OBD port in the glove box but I'm not sure what you mean by 'fly by wire'

I've had various niggles including a major water leakage issue that is due to get sorted out next week. Could something be getting short circuited somewhere?
It could be as simple as a leaf or other debris causing the throttle to stay open.
I have personally faced this situation once in my Baleno. The throttle cable was stuck due to a loose plastic part in the engine bay. I had to stop the car and dislodge the plastic to release the stuck throttle.
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Old 14th December 2012, 15:56   #98
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Default Re: RPM shoots up when changing gears

Kindly have look at the clutch switch.!
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Old 14th December 2012, 16:50   #99
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Default Re: RPM shoots up when changing gears

Quote:
Originally Posted by mathewpn View Post
verito does have drive by wire, and yes, the same RPM shoot up happened with me also only to find the floor mat playing fool with the accelerator pedal. Set that up correctly and no problems so far.
Quote:
Originally Posted by msaudf View Post
i had the same issue while i drove to bangy in my friend's C class, but then i kinda adjusted my driving style, depressed the clutch a little late when i wanted to shift gears, ......... i noticed that everytime i lift off the accelerator and touch the brake pedal the revs drop creating engine braking, even if i did them instantly.
but like some of our friends who get their floor mats to operate the accelerator for them beware (just kidding),
Ok on a serious note: this rev shooting issue due to the floor mats being improperly laid could get you panicky during emergency braking.
Thanks Mathew & msaudf, I have a wet carpet after a water leak into the passenger area. All my 'extra' carpets were off except this plastic mat that I took from the rear and placed it temporarily on the driving seat floor. It is too short to reach anywhere near the pedals.
The rev shooting did not stop even after I braked to a halt, but after I switched off for 15 seconds

Quote:
Originally Posted by acroback View Post
Yes I face this on my Duster, when I press my clutch sometimes. Instead of slowing down it just shoots ahead. Is this what you are talking about, Woodcrawler?

I think it is normal for Duster. You need to adjust your driving style for this car a little.

This is not consistent though. Especially more likely to be seen when you press the clutch immediately after you release your accelerator.
Thanks Acroback, this is the first time I had this experience but there has been no change in my driving style from the day I got the Duster. It caught me off guard but I had the presence of mind to brake slowly because the vehicle wasn't misbehaving.

Quote:
Originally Posted by 1self View Post
Momentary rev hang is an ECU condition set up by the car manufacturers to enable complete combustion on sudden throttle lift off. It is an emmissions requirement.

If the rev hang is prolonged, it means either:
1. You have a small vaccum leak.
2. Your throttle cable (if present) need adjustment.
Thanks 1self. I'll keep that in mind but I can't recall lifting my foot off the accelerator suddenly. I was actually slowing down behind a bus.

Quote:
Originally Posted by speedmiester View Post
It could be as simple as a leaf or other debris causing the throttle to stay open.
I have personally faced this situation once in my Baleno. The throttle cable was stuck due to a loose plastic part in the engine bay. I had to stop the car and dislodge the plastic to release the stuck throttle.
Thanks speedmiester, but definitely nothing in the engine bay!

Quote:
Originally Posted by varunlaxman View Post
Kindly have look at the clutch switch.!
Thanks Varun, will have a look if it happens again.
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Old 14th December 2012, 22:43   #100
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Default Re: RPM shoots up when changing gears

Quote:
Originally Posted by woodcrawler View Post
The rev shooting did not stop even after I braked to a halt, but after I switched off for 15 seconds
yes i've been reading ur posts about the unfortunate carpet damping in your car, i feel for you my man.
but this rev shooting up is not normal from what you've described, there seems to be some problems with the sensors of your throttle. its best you have them checked at the A.S.S.
do you think all the water and dampness could be messing with any sensors inside the cabin? just a hunch
check it out man. again, i feel for you man .
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Old 15th December 2012, 07:11   #101
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Default Re: RPM shoots up when changing gears

Quote:
Originally Posted by msaudf View Post
yes i've been reading ur posts about the unfortunate carpet damping in your car, i feel for you my man.
...........
do you think all the water and dampness could be messing with any sensors inside the cabin? just a hunch
check it out man. again, i feel for you man .
Thanks msaudf, that was what I thought too but the problem has not recurred. I am taking it for 1st service on 18th anyway so I'll report it then
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Old 15th December 2012, 10:53   #102
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Default

Quote:
Originally Posted by woodcrawler View Post
I was driving in town today through the usual route in third gear and just as I was about to overtake a slowing bus the engine started racing on its own.

I had depressed the clutch and got the leg off the accelerator when this happened. I parked the vehicle and switched it off and when I restarted it the engine was still revving automatically. I switched it off for about 15 seconds and the restarted again. No problem. Till I reached back there has been no repetition of the event.

Do any Renault Duster owners have a similar problem? If so how was it solved. I am due for 1st service on 18th. What should I report if I have no similar experience during the intervening period?

Rajesh
Ask them to check throttle cable. I had exactly same issue with swift and rpm shot up to 6k without me giving any press. Scary

Other issue could be throttle body but your car is pretty new. So my guess is faulty cable
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Old 15th December 2012, 23:35   #103
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Default Re: RPM shoots up when changing gears

Revs increasing suddenly without proportional throttle input is not normal. This is something wrong which somehow has found acceptance under the banner of many names. Rev hang was originally for racing or track days where during gear shift when the throttle is suddenly lifted off, the revs wont drop keeping the engine is proper powerband. This was later on adopted on normal day to day passenger cars for emission reduction.

Duster does not have this feature to the best of my knowledge, else this would come up in multiple reviews that I have read. Do correct me if I am wrong. Sudden acceleration due to mats is not likely as it would actually hamper full flooring of throttle, but this can vary as per car's throttle pedal design and floor mats.

The most likely possibility that comes to my mind is that the engine was cold and ECU was trying bring engine to operating temperature and hence increased the RPM. This is normal as I have observed this even in old cars like Balneo, City and even in Swift. But this increase would be seriously very slight, may be 250-500 rpm max., not WOT. This is just for initial startup period, not when the car is running on the road.

Take the car to A.S & S. Duster is too new a product to research and arrive at conclusions. Its just not correct to have a car out of control due to unintended acceleration. There is something not correct, be it throttle pedal design, floor mat design or anything, but at the end of the day, this unintended acceleration must not happen ever again.

Last edited by aaggoswami : 15th December 2012 at 23:37.
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Old 16th December 2012, 00:18   #104
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Default Re: RPM shoots up when changing gears

Great I found this thread! Won't have to create a new one for my problem.

I have a 2010 Ritz ZXi. Off late, around a month, the car started showing symptoms like the ones mentioned here.

Driving in gear 3.
RPM is around 1.5 - 2K
Depress Clucth.
Change Gear to 4.
RPM stays for normal for ~1 sec and then shoots to 3-4K.
Stays there for ~1 sec.
Comes back to where it should be.

I remember noticing this after I accidentally dropped a Limca 2 Ltr. cap in the bonnet (while filling the washer compartment with water,) near the radiator. I tried getting that cap out but could not find it. I don't know if it is related to the incident or not but found only after the incident.

The car has its service due will try to replicate the issue in front the MASS (generally the problem is reproducable) and see if they have a solution. The car is not showing any ECU light.

In case I lift my foot of the throttle while changing grear this problem doesn't occurs.

I second #aaggoswami. I doubt this is because of Drive by wire because this is something that I noticed recently after owning the car for around 3 years.

Last edited by anupamsinha : 16th December 2012 at 00:20.
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Old 16th December 2012, 08:21   #105
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Default Re: RPM shoots up when changing gears

Quote:
Originally Posted by anupamsinha View Post
In case I lift my foot of the throttle while changing grear this problem doesn't occurs.
You ARE supposed to lift your foot off the accelerator when changing gears. When you push the accelerator while changing gears, there will be a point when there is no load on the engine. Then the revs will rise suddenly.
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