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Old 9th November 2008, 01:03   #16
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does this occur when you step off the accelerator ?
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Old 9th November 2008, 01:07   #17
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does this occur when you step off the accelerator ?
yes when in city i accelerate and then when i put my feet off the accelerator then i hear this sound. i dont hear this while accelerating.
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Old 9th November 2008, 01:16   #18
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Post Deleted by the Team-BHP Support : SMS / Slang is STRICTLY prohibited on this community. We would much appreciate your using full & proper english in posts, for the benefit of other forum users.

Please view our board rules carefully before proceeding any further.

Last edited by GTO : 10th November 2008 at 18:24.
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Old 9th November 2008, 01:16   #19
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looks like engine tune-up needs to be done : this is probably the sound of the engine backfiring.
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Old 9th November 2008, 01:18   #20
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looks like engine tune-up needs to be done : this is probably the sound of the engine backfiring.
do u mean to say misfiring? mine is alto 800 cc MPFI engine, i doubt there is much scope of tuning in this!!
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Old 9th November 2008, 10:40   #21
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have you got engine de-carb ?
I hope its not a leaky exhaust valve.
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Old 9th November 2008, 19:04   #22
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Leak in exhaust pipe.
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Old 9th November 2008, 19:39   #23
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get the injectors cleaned buddy..

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Originally Posted by amit_mechengg View Post
do u mean to say misfiring? mine is alto 800 cc MPFI engine, i doubt there is much scope of tuning in this!!
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Old 9th November 2008, 23:14   #24
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is it that my exhaust is blocked, because the same thing had happened with my bike and the silencer had got clogged. do i need exhaust cleaning?
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Old 10th November 2008, 11:05   #25
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is it that my exhaust is blocked, because the same thing had happened with my bike and the silencer had got clogged. do i need exhaust cleaning?
Most probably a ruptured joint in the exhaust, put it on a ramp and check.
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Old 10th November 2008, 11:11   #26
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The same thing happened with my car after I got a FFE. Changed the FFE thrice after that, but the sound remains.
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Old 10th November 2008, 22:50   #27
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Quote:
Originally Posted by Blue Thunder View Post
looks like engine tune-up needs to be done : this is probably the sound of the engine backfiring.
Quote:
Originally Posted by amit_mechengg View Post
do u mean to say misfiring? mine is alto 800 cc MPFI engine, i doubt there is much scope of tuning in this!!
There is the possibility of misfiring even in the case of MPFI engines with ECU : as long as it is spark ignited, this possibility exists. There could be something wrong in the ECU, which could be sending the charge at the wrong time to the sparkplugs.

I am giving this as a likely cause, since you have mentioned it happens only while decelerating , and not all the time.

Anyway, time to get it examined at a good garage, since continued running in this condition will deteriorate the engine in the long run.
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Old 10th November 2008, 23:48   #28
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Shan2nu's right. That "misfire" is technically due to an overtly rich/lean mixture/AFR at zero throttle.

@Cyrus43: Technically, the engine is never "zero-fuelled". Even at zero-throttle, the engine receives enough fuel to idle. Although the TB is at zero degrees, IACV supplies minimal air and the injectors (or in this case, carb), fuel. When that fuel does not receive enough air to supplement it's combustion, unusual combustion such as this "popping" happens.

This phenomenon is far more apparent in carbs, giving the impression of "tuned FI's".

@sumeet: Check your idle solenoid.. get your carb serviced, and replace the primary jet & primary & secondary needles, if necessary.

Last edited by veyron1 : 10th November 2008 at 23:50.
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Old 11th November 2008, 00:17   #29
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Quote:
Originally Posted by veyron1 View Post

@sumeet: Check your idle solenoid.. get your carb serviced, and replace the primary jet & primary & secondary needles, if necessary.
ya my idle solenoid is having problems currently as the throttle body is clogged due to K&N filter passing on dirt in it. while idling the rpm fluctuates.
so it is due to this i am facing the exhaust problem?
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Old 11th November 2008, 10:20   #30
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Quote:
Originally Posted by veyron1 View Post

@Cyrus43: Technically, the engine is never "zero-fuelled". Even at zero-throttle, the engine receives enough fuel to idle. Although the TB is at zero degrees, IACV supplies minimal air and the injectors (or in this case, carb), fuel. When that fuel does not receive enough air to supplement it's combustion, unusual combustion such as this "popping" happens.
No. Conditions at zero throttle and RPMs above a certain limit (~2000) will enable a fuel-cut operation to cut emissions and increase FE. All modern day cars have this feature.
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