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Old 7th May 2009, 20:22   #1
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Default Weird Issue: Engine jerks on deceleration?

I have just noticed that my Esteem MPFi has been jerking considerably and engine speed falls off very very quickly (alarmingly so) when I let off the throttle. I never feel like the car is going to stall, but this drop of RPM's is highly unnerving.

Feels like someone has applied the brakes (just a feeling, it's surely not true, since the car rolls well in neutral, hence nothing to do with jammed brakes or pad/disc touching the wheels unnecessarily)

SO when i do, say 2500 RPM in 1st and depress the clutch to change to 2nd, the car jerks quite violently and feels like the clutch is retarding the engine way too fast. the moment i shift to 2nd, its smooth as hell, but again, the 3rd gear change evokes the same jerky change. 4th and 5th are done at higher revs and higher speeds, hence perception of that jerk is nigh impossible.

Also, the engine feels slightly jerky on acceleration. Gear change from 1st to 2nd also gives out a crunch (which causes me to wince and say OUCH, but this has been happening since a long time: feels normal)

Can i attribute it to the clutch? I have no idea, but what could be the issue?
OR could it be plainly an accelerator cable gone awry and playing havoc with the engine at will?
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Old 7th May 2009, 20:30   #2
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Adjust your clutch play before anything else.
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Old 7th May 2009, 20:46   #3
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I'm am no expert, but looks like your clutch is not dis-engaging the transmission fully causing some amount of engine braking to seep in. Like Jaggu said, I'd say check your clutch play. About the jerks while accelerating, I had a similar issue in my MPFI Zen too. A good clean up of the injectors resolved it. Good luck!

Cheers!
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Old 7th May 2009, 20:57   #4
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oh the injectors have just been cleaned and the high tension cables have been replaced.
also, as far as the play is concerned, I am quite sure on one has touched it in a while.

@dueller: what is exactly the issue that is making the clutch not disengage the transmission?
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Old 7th May 2009, 21:18   #5
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@ frankmehta: Check clutch pedal free play. You've probably got a loose or frayed clutch cable, which is preventing the clutch from disengaging completely when you depress the clutch pedal. Also the reason your gearshift is sticky/noisy. It's a minor issue. Might need a change of clutch cable.
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Old 7th May 2009, 21:24   #6
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Quote:
@dueller: what is exactly the issue that is making the clutch not disengage the transmission?
Again, just a attempt at what I think might be wrong: Because the Esteem uses a cable operated clutch, any shortfall/excess of cable length might cause the clutch to not fully dis-engage. As a result, under no thottle input (as in, while changing gears) the partially-engaged transmission could cause the car to jerk and decelerate faster as compared to a fully dis-engaged transmission. It would also make changing gears more difficult depending upon the severity of the play.

Though I have not seen this happen in my car, I have seen this happen umpteen number of times in my bike. The clutch actuator besides the kick starter would not turn completely when the clutch cable is not adjusted properly, making changing gears harder and decelerating quickly when the clutch is pressed.

@frank: Do you notice any difference in the amount of effort required to change gears?

Cheers!
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Old 7th May 2009, 23:53   #7
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I am no expert, however , similar problem with my Indica was taken care by changing clutch plates. Fortune motor told me that there was some oil leakage in clutch assembly leading to malfunction.

It never returned since then.
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Old 8th May 2009, 02:28   #8
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I would suggest get the following checked.

1)Clutch Plate
2)Complete exhaust system

When i heard your car,i felt as if it has a leakage on some joints and the sound/performance and acceleration has gone flat.
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Old 8th May 2009, 03:40   #9
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Check your fuel pump. Irregular supply of fuel due to being clogged sends less fuel as per required. The ECU reads it as insufficient supply and can put air/fuel ratio in lean mode. Also, get your knock sensor checked.

And as other said get clutch checked or the clutch setting.
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Old 8th May 2009, 09:45   #10
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I had exactly the same problem that started a few weeks ago on my U-VA - jerky gear shifts, sudden (more than normal) engine braking effect, engine cutting off when I release the clutch at standstill etc. I had time constraints and hence could not go to the service center to get the clutch setting checked. I have always used Normal petrol + System G.

It just so happened that I did not have access to System G for the last two refills. Hence decided to go with Speed petrol. Have had a refill of Rs. 500 for the last two weeks on Speed and the problem seems to have reduced considerably since the last one week.

Asked an expert and here is what he tells me - in summers, the refineries increase the quantity of naptha in petrol to reduce evaporation losses. Premium or Speed petrol still seems to maintain the quality (lesser naptha). Naptha tends to clog the fuel and injection system. He suggested that I switch to Speed for the summers and also avoid going full tanks. He also recommended, because my car is mostly driven in the city, that I do a sprint every two weeks or so to burn off the deposits.

The explanation seems to make some sense to me - at least switching to Speed for the time being has reduced my problem to a significant extent!

Last edited by the_maassk : 8th May 2009 at 09:48.
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Old 19th March 2010, 17:35   #11
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Quote:
Originally Posted by the_maassk View Post
. He also recommended, because my car is mostly driven in the city, that I do a sprint every two weeks or so to burn off the deposits.
How do deposits form while driving in the city?
What do you mean by sprinting? Long drives?
And how does sprinting help burn the deposits?
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Old 19th March 2010, 20:25   #12
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Seems more likely to be the clutch pressure plate issue
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Old 5th April 2010, 15:17   #13
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I have a 1998 model Matiz. I loved the drives and never wish to change the car (Thank goodness, spares are still available).

In December 09, i had a coolant leak. I realised this as my engine temperature shot up and a white smoke like steam came from under the hood (when i parked). As it was night, i drove around 3 kms to home (i would switch off the engine as soon as the temperature gauge would touch red, glide and switch on again). I spoke to the mechanic who advised me to bring the car next morning by adding water in the coolant bottle.

Next morning, as i added water, it just drained out below. Anyhow, I drove to the mechanic ( only 1 km away). He opened the car and showed me that the an assembly (right in the middle of the hood, had coolant intake from one side; the coolant pump was also seen near this entry) had cracked. Pardon me for being so less tech savvy, but then thats why i am posting this here for help.

He informed that a new assembly (it seemed like a plastic container to me), would cost around Rs 5000 but he could seal the leak with m-seal. I agreed for the m-seal option.
I also got the fuel injectors cleaned and calibrated at his advice.

The coolant has stayed in tank ever since. However, while driving, on lower rpms, the engine jerks (as if am not in correct gear). If i release the accelerator and slowly accelerate again, the engine is able to pick up speed.

This is my problem. As I have another car, I have driven Matiz very little since then.

Can anyone here advice me as to what is wrong in my car and how it can be rectified?

I loved the way my car drove and am determined to get her back to the way she did.

Thanks
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Old 5th April 2010, 19:34   #14
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Exactly the same problems i am having with my old diesel indica. For the first part of the problem- the jerks at gear change, definately the problem is with clutch , and if one were to be specific, parts of clutch: pressure plate, diapgram spring, knock-out bearing and finaly adjustment may be needed for clutch cable.
As for second part of problem, i have been told to replace noozles in my car since the fuel pump of my car was fine. So, for your, check fuel pump and injectors, also verify if there is need for the adjustment of that cable that connects the accelerator pedal with the throttle valve.
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Old 6th April 2010, 10:16   #15
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Dippy, I really doubt on your injector. As you had mentioned that the mechanic had serviced the injectors, they might have either got damaged or are not delivering the correct amount of fuel. Since the engine friction is more at lower rpms (owing to lower piston speeds), any change in injection pattern might get refelected in lower speeds. Sparkplug performance can also be doubted. If the spark gap is less due to carbon deposits, this problem can happen
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