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Old 27th February 2008, 13:59   #1
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Default Mahindra Commander Engine exhaust

hi
our Mahindra Commander 1997 model (XDP 4-90 ;2112cc diesel engine) jeep is giving out white smoke when its at idling rpm and when a little throttle is given, the white smoke disappears and moreover what could be the main reasons for these high exhaust fumes can they be rectified? what would be the cost involved for the job.
thanks in advance

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Old 27th February 2008, 14:48   #2
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could you tell me how much has the engine clocked, also if the engine was overhauled recently, if yes there are small washers that fit on the injectors were they touch the head [the nozzle] , sometimes mechanics tend to forget this while putting it after servicing of the engine nozzle cleaning, by not putting this in place there is an uneven spray of fuel and whence the engine smokes at ideal this could be one cause.
Or the injection system needs cleaning.
This will be only if the engine smokes when at ideal not if it smokes through out the rev range.
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Old 27th February 2008, 14:50   #3
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It could be either the coolant or diesel mixing with the engine oil. Either way , white smoke in a diesel engine is not good, and you should get it checked at the mechanic soon.
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Old 27th February 2008, 22:21   #4
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Quote:
Originally Posted by Blue Thunder View Post
It could be either the coolant or diesel mixing with the engine oil. Either way , white smoke in a diesel engine is not good, and you should get it checked at the mechanic soon.
I believe that is not the case with mine as i have checked for this factor already neither is my jeep drinking oil nor coolant ... moreover that is only applicable when the engine is emitting white smoke throughout the range of rpm right???
by the way the case you mentioned i remember reading it in a book .... anyway thanks a lot

Last edited by rranjith_kum : 27th February 2008 at 22:34.
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Old 27th February 2008, 22:42   #5
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Quote:
Originally Posted by dinar View Post
could you tell me how much has the engine clocked
My jeep is a second hand (i will let you know the exact odo figure by tomorrow) i am afraid the odo isn't showing the exact figure as i suspect it has been altered

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if the engine was overhauled recently
i haven't done it till now don't know how the previous owners had maintained it ... i will do this very soon expecting a good repair job for it

Quote:
Originally Posted by dinar View Post
if yes there are small washers that fit on the injectors were they touch the head [the nozzle] , sometimes mechanics tend to forget this while putting it ..........Or the injection system needs cleaning
i will check for it definitely
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Old 27th February 2008, 23:18   #6
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From my experience, i think its the engine oil entering the combustion chamber which means you will need a rebuild or new engine.

If this jeep is for your/personal use,i would suggest retrofitting a bolero engine.It should cost around 20-30k depending on how much the engine vendor values your current engine for exchange.
Check around cbe if there are any bolero engines available .If not, let me know.
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Old 28th February 2008, 00:05   #7
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Quote:
Originally Posted by rranjith_kum View Post
hi
our Mahindra Commander 1997 model (XDP 4-90 ;2112cc diesel engine) jeep is giving out white smoke when its at idling rpm and when a little throttle is given, the white smoke disappears
Worn out valve guides/valve stem seals. Smoke in such a situation will not be present once the vehicle is out of the idle range or in normal running.
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Old 28th February 2008, 01:21   #8
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^^possible.
Quote:
Originally Posted by sankar
Smoke in such a situation will not be present once the vehicle is out of the idle range or in normal running.
Bro, why is this phenomenon only at idle?
Im guessing it has to do with the vacuum. Right?
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Old 28th February 2008, 13:52   #9
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Quote:
Originally Posted by nitrous View Post
^^possible.

Bro, why is this phenomenon only at idle?
Im guessing it has to do with the vacuum. Right?
I guess so nitrous anna, vacuum is a logical. Such a situation is usually the result of worn out guides and/or bad stem seals.

But in this case it being a diesel and since diesels don't have throttle plates i don't know if it's entirely due to the vacuum. I could be wrong.

Last edited by Sankar : 28th February 2008 at 13:53.
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Old 28th February 2008, 14:04   #10
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hey if the engine is due for overhaul, take nitrous's advice since it's a secondhand vehicle the condition of the engine may be real bad and getting these engines to good condition is not that easy if it is not maintained properly by the previous owner.
plus one has to spend 20k or more for an overhaul , so rather buy something in better condition and the bolero engine is better 2.5L [75 bhp].
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Old 28th February 2008, 15:16   #11
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Most likely a pump timing problem.

* Is this a DI engine or an IDI engine?
* Is the pump an in-line pump (all delivery pipes in one line) or a distributor pump (square top)?

If this is an IDI engine, the chambers are cooling down too fast, promoting incomplete burn. If DI, there must be slow coolant leak somewhere, probably through gasket.

Bigger worry would be black or blue smoke, not the bluish-white/white.
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Old 28th February 2008, 17:13   #12
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Here is a youtube video of my jeep's exhaust .... this may be of some help to the experts. Kindly bear with the video quality its was taken from my nokia n70 mobile



the engine was started the raised for about 50% of the throttle and then left then once again given throttle gradually

Last edited by rranjith_kum : 28th February 2008 at 17:16. Reason: addition of information
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Old 28th February 2008, 17:30   #13
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Quote:
Originally Posted by nitrous View Post
If this jeep is for your/personal use,i would suggest retrofitting a bolero engine.It should cost around 20-30k depending on how much the engine vendor values your current engine for exchange.
Its not for personal use anna ... it was bought for my dad's marketing purposes
the engine has clocked 26k kilometers on the odo and my mechanic is saying its been rebored and at that time the odo would have been reset.
it giving a mileage of about 10-11kmpl ... as a rough guide it should have done atleast 1.25lac kms

i don't know what will be my dad's response for retrofitting it with Bolero's engine !!!
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Old 28th February 2008, 18:30   #14
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Quote:
Originally Posted by DerAlte View Post
Most likely a pump timing problem.

* Is this a DI engine or an IDI engine?
* Is the pump an in-line pump (all delivery pipes in one line) or a distributor pump (square top)?

If this is an IDI engine, the chambers are cooling down too fast, promoting incomplete burn. If DI, there must be slow coolant leak somewhere, probably through gasket.

Bigger worry would be black or blue smoke, not the bluish-white/white.
mine is a IDI engine (i think so) ... but i am unable to understand what your are trying to mean ... is the cooling system working ultra efficiently in my case??
the phenomenon of white smoke is when the engine is run at cold temperature right?? but even after a half an hour drive then at idle this crappy engine is smoking white so i ruled out the cold engine start also from the text.

Last edited by rranjith_kum : 28th February 2008 at 18:44. Reason: spelling
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Old 28th February 2008, 18:54   #15
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No, white smoke (bluish-white smoke really) can come at any temperature, but the reasons differ. In your case it is constantly present - you see it more at idling when the gas flow rate is less; at higher rpm it is faintly visible as compared to the main exhaust gases due to higher flow rate.

In your case either there is a coolant leakage (the additive burns, the water evaporates in the cylinder and condenses in the silencer) or the pump timing is out slightly. Not sure how to describe it, but this is the equivalent of spark firing too early before TDC - too much advance.

Basically, the cylinder temperature is not high enough and post-combustion some of the exhaust vapours condense into a while smoke. Quite different from black smoke, where the fuel itself is partially burnt - producing soot.
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