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Old 13th June 2014, 12:18   #16
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Default Re: Engine Jerking

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Originally Posted by pramodkumar View Post

It happens mostly during evenings and after 1-2 KMs of running, it happens when it rains. i didn’t experience it today morning while coming to work, it was over cast today and was reasonably cold

Pramod

It indicates the problem arises when the engine heats up.

1)Can it be the fuel pump showing its age? Faulty fuel pumps tend to give up when engine gets heated up.

2) It mainly happens when it rains so may be there is some leakage from where the rain water is entering the fuel line or moisture is forming up in the spark plug or so which can result in the jerk.

I faced a similar problem in our Fiat Uno. It became really tricky to figure out whether it was a fuel line issue or an electrical issue. Later it was solved by adjusting the tappets. You can have a look at the thread if it can help you.

http://www.team-bhp.com/forum/techni...-resolved.html (Trouble with my Fiat Uno Petrol. EDIT : Now Resolved!)

Last edited by Samba : 13th June 2014 at 12:21.
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Old 13th June 2014, 13:32   #17
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Default Re: Engine Jerking

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... 1)Can it be the fuel pump showing its age? Faulty fuel pumps tend to give up when engine gets heated up. ...
A failing / failed fuel pump is unable to build-up the pressure in the rail (both diesel as well as petrol). If the rail pressure is insufficient, injection is insufficient - for *ANY* cylinder. This means the engine will not start, or lose power (but continue to run), or stall - depending on when the failure had occurred and how big the failure was. Fuel Pump failures won't cause intermittent missing.

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... 2) It mainly happens when it rains so may be there is some leakage from where the rain water is entering the fuel line or moisture is forming up in the spark plug or so which can result in the jerk. ...
These are definitely possibilities, but is a slightly different way:
* Water would already be present in the fuel (at the filling station itself), and there is no possibility of it leaking into the fuel system after the tank
* In a hot engine, it is unlikely that condensation will affect spark plug, which is also hot. However, if there is condensate near a crack in the cable (in @Pramod's case he has replaced the spark plug cables), electricity may be conducted away causing spark failure
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Old 13th June 2014, 13:57   #18
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Default Re: Engine Jerking

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I assume they didn't tell you what was the reason and what did they do to fix it in each case.

.
You are right they didnt, when i insisted to know, he said he cleaned the TPS and reseated it.

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Keep bonnet open, car in neutral - wherever you are parked. Disconnect air filter so that you can look into the throttle body. Ask someone to do the same thing as you described (doesn't have to be in gear).
1. Whenever the problem occurs, try to isolate where the sound is coming from: Throttle body? Exhaust? ...

.
It does not happen when the car is standing( or i have not observed it), it spits once in 1-2 KMs and then it does not for a very long time. I have reved the engine it goes all the way till 7k with and the car pulls effortlessly, it happens when i try to build revs immediately after nearly lugging the engine, and sometimes during lift-off (seems electrical and not fuel pump related), this is the main reason i replaced the HT cable and spark plugs

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2. Try to observe the behaviour of the throtte vane (the circular vane that rotates in the throttle body) when trying to replicate the problem (try to correlate it with the engine rpm). Does it have an odd behavior when the 'spitting' happens?.
could be vaccum related, i need to take my car to someone who knows his stuff.

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3. When 'spitting' happens, does the engine shudder?
No, it just skips a beat and then its ok, it happens for like a second max and its fine,

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Could be! Go break some coconuts in a temple!!!.
I have the power of lord ganesha, just installed a nice looking statue, and looks like its working since i am getting help

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To be expected - belies the fact that they didn't have a clue.
True that, thy have no clue about anything, there is a small oil leak from the distributor, needs an o-ring replacement, its been 2 years since i randomly place orders and wait for parts and nothing happens. These guys are killing the brand on purpose.

Pramod
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Old 13th June 2014, 14:13   #19
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Default Re: Engine Jerking

I'd take a look at the distributor as well. My previous car, a Ford Ikon had something similar and it turned out to be the distributor. With the Ikon, the distributor comes attached with the high tension leads and plug caps. Set me back quite a bit.
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Old 13th June 2014, 15:37   #20
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Default Re: Engine Jerking

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It happens mostly during evenings and after 1-2 KMs of running, it happens when it rains. i didnít experience it today morning while coming to work, it was over cast today and was reasonably cold
Have you checked the ignition coil? Engine missing after running for some time can be due to a faulty overheating ignition coil. How many ignition coils does the lancer have, 1, 2 or 4?
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Old 13th June 2014, 16:14   #21
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Default Re: Engine Jerking

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You are right they didnt, when i insisted to know, he said he cleaned the TPS and reseated it. ...
Heh there is nothing to clean there - it is a sealed unit.

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... It does not happen when the car is standing( or i have not observed it), it spits once in 1-2 KMs and then it does not for a very long time. ...
Wouldn't have anything to do with being in gear or not, stationary or driving.

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... could be vaccum related, i need to take my car to someone who knows his stuff. ...
Observe first before inferring anything, please.
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Old 13th June 2014, 17:11   #22
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Default Re: Engine Jerking

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Have you checked the ignition coil? Engine missing after running for some time can be due to a faulty overheating ignition coil.
Could be, that was the next thing to attack logicaly. My present mechanic does not have a timing gun so had to skip that, i am taking my car to a different guy today. Before anybody jumps on me i have checked the timing from A S S, its spot-on

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How many ignition coils does the lancer have, 1, 2 or 4?
I have no idea, its not like a cylindrical thing like in marutis

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Observe first before inferring anything, please
true, i am taking it to a new set of guys today. The appointment is set. I have an outing tomorrow, that gives them the whole day to isolate the issue.

Thanks a lot all for the support

Pramod
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Old 13th June 2014, 17:19   #23
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Can be very frustrating these sort of problems. As usual your first port of call should be to try and read the codes. But failing that and the symptoms as described I would suspect something in the ignition system. derAlte pointed out already, but not only your spark plug cables could be the problem, you might want to check the distributor gap for internal wear and tear as well. Just like the spark plug cables over time they tend to crack with all sorts of funny effects on the ignition effectiveness. An easy test on the overall state of all your high voltage components: in the dark, start the engine and spray water through a very fine nozzle on everything, cables, distributor cables, coils etc. you need to ensure its really like a fine mist. If there are any cracks you will see sparking. If you do, you have found the culprit.
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Old 13th June 2014, 18:48   #24
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Default Re: Engine Jerking

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Originally Posted by pramodkumar View Post
Could be, that was the next thing to attack logicaly. My present mechanic does not have a timing gun so had to skip that, i am taking my car to a different guy today. Before anybody jumps on me i have checked the timing from A S S, its spot-on
Correct timing doesn't prove ignition coil(s) is OK. The workshop manual will have the values and the steps to diagnose a faulty ignition coil.

The video is just a guide for info
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Old 13th June 2014, 19:43   #25
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Default Re: Engine Jerking

My God! If I was Kary, I would be even more confused now then before the post. It's a drivability problem nothing all that complicating. For combustion you need air, fuel, compression and spark. The proper way to diagnose a problem is to do just that, diagnose! You can't fix the problem by guesswork and by swapping parts.
Kary, e-mail me your phone number at ray32825@yahoo.com and let's see if I can help you figure out the problem.
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Old 13th June 2014, 21:33   #26
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Default Re: Engine Jerking

PramodKumar, what is the year and engine size of your Mitsubishi? I am assuming from the thread that your engine has a distributor and was wondering if you changed the rotor and cap when you changed the spark plug wires. If not please do so, and make sure you have no moisture inside the distributor by spraying it down with some WD-40.

Assuming that you have no moisture around the spark plugs, the best way to figure out if you have a problem in the high tension side of the ignition is to check it at night. Have someone sit in the car and put the engine under load by engaging first or reverse. Rev the engine very slightly and try not to stall it by keeping a foot on the clutch. Needless to say, make sure that you have the emergency brake on while performing this test. If you have a problem in the high tension side of the ignition you should be able to see or hear the spark arcing somewhere. Since your spark plug wires a new there is no need to spray them down with some water.
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Old 16th June 2014, 08:52   #27
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Default Re: Engine Jerking

I come with new data, the spitting happens ~ 1500 RPM. and now i am able to replicate it. its fine after that till redlining and below that RPM.

^^ my car is a 1999, its a 4G15 MPFI.


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Old 16th June 2014, 17:11   #28
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Default Re: Engine Jerking

Dear Kary

This could be due to the engine mounts.
The Ikon engine is mounted on to a holder having rubber mounts.

These rubber mounts harden over time and become brittle leading to the engine jerking.

Also, if this doesn't solve the issue, you could do a throttle body cleaning.
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Old 16th June 2014, 18:07   #29
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Default Re: Engine Jerking

Pramod, That's great, it looks like we have the same size engine on a Mirage in the US. Now, when you say spitting, I'm assuming you mean jerking/hesitating/missing and that this can be replicated at 1500 rpm with the transmission in neutral (engine being hot or cold) correct?
Also did you change your distributor cap and rotor, and is this what your engine layout looks like? (Fig from MOD5)
Attached Thumbnails
Engine Jerking-screenhunter_71-jun.-16-07.48.jpg  

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Old 16th June 2014, 19:10   #30
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Default Re: Engine Jerking

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Pramod, That's great, it looks like we have the same size engine on a Mirage in the US. Now, when you say spitting, I'm assuming you mean jerking/hesitating/missing and that this can be replicated at 1500 rpm with the transmission in neutral (engine being hot or cold) correct?
Also did you change your distributor cap and rotor, and is this what your engine layout looks like? (Fig from MOD5)
Yes its same as the mirage in us in the mpi avatar, this happens only on load only and not during idling and out of ten time it happens 7- 8 times. Mostly happens when hot but sometimes cold as well, the layout is the same. No the distributor cap or shaft has not been changed yet, should I?

Pramod

Last edited by pramodkumar : 16th June 2014 at 19:13.
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