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Old 31st August 2010, 08:08   #1
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Default Why does my engine feel better when cold?

Hi,

When I start my car for the first time, i.e. when the engine is cold, my car performs much better than it does when the optimum temperature is reached. On the first start the engine revvs more freely, the engine noise is also significantly low and the car drives much faster.

Anyone else noticed the same, anyone knows the reason for the same?

I drive a fiat punto diesel

Thanks
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Old 31st August 2010, 09:37   #2
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That sounds like the exact opposite of how most engines behave! Cold start clatter is significantly higher, and the engine is NOT supposed to be revved hard till optimum temperature is reached.

Are you sure your engine is not OVERheating?
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Old 31st August 2010, 17:25   #3
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No mate, the engine temperature does not exceed half the mark. I dont usually redline, upshift at 3000-3500 rpm.

Weird right?
P.S. im also running pete's box and a stock replacement k&n filter
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Old 31st August 2010, 18:28   #4
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This defies all known logic and technicality. When cold, the engine and its various moving parts are devoid of any lubricant, with the oil having settled down in the sump.

Because of this the parts run dry for a few seconds before the oil reaches every nook & corner. And when it runs dry, the clatter is more and the friction too is more.

Once the oil reaches everywhere and lubricates, the sound settles down to a decent purr.

Your Punto's behaviour is strange...

Quote:
Originally Posted by fink_ployd View Post
Hi,

When I start my car for the first time, i.e. when the engine is cold, my car performs much better than it does when the optimum temperature is reached. On the first start the engine revvs more freely, the engine noise is also significantly low and the car drives much faster.

Anyone else noticed the same, anyone knows the reason for the same?

I drive a fiat punto diesel

Thanks
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Old 31st August 2010, 19:22   #5
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Quote:
Originally Posted by fink_ployd View Post
No mate, the engine temperature does not exceed half the mark. I dont usually redline, upshift at 3000-3500 rpm.

Weird right?
P.S. im also running pete's box and a stock replacement k&n filter
Strange behavior and defies logic. Isn't it too high to up-shift at 3000-3500 RPM for the Diesel ? What is the recommended shift pattern in Punto user manual.
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Old 31st August 2010, 21:17   #6
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Quote:
Originally Posted by SS-Traveller View Post
That sounds like the exact opposite of how most engines behave! Cold start clatter is significantly higher, and the engine is NOT supposed to be revved hard till optimum temperature is reached.

Are you sure your engine is not OVERheating?
+1. In all the cars I have driven it has always been the opposite. In my newest car (SX4), the engine clutter is high for first few minutes and once the engine warms up to the optimum operating temperature, it becomes smooth, refined, and also a lot quieter.

I guess there is some problem that you may want to look out for.

Last edited by Dr.AD : 31st August 2010 at 21:18.
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Old 31st August 2010, 22:59   #7
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Quote:
Originally Posted by fink_ployd View Post
When I start my car for the first time, i.e. when the engine is cold, my car performs much better than it does when the optimum temperature is reached. On the first start the engine revvs more freely, the engine noise is also significantly low and the car drives much faster.
Strangely enough, I have noticed the same phenomenon in my dad's OMNI(1996). I have felt that it accelerates better during early mornings. Only the acceleration was better, but the engine noise is a bit on the higher side and the engine seemed smooth only when it was warmed up.

Does this have something to do with lubrication?. Like the oil exerting somekind of backforce in the pistons?. because this 'boost' is there only till the engine warms up.

Experts, please comment.

And, this was felt ONLY in the OMNI, and our Ambassasdor diesel had a very noticeable performance difference when the engine was warmed up. While driving my IKON, my dad still says that, once his amby is 'heated up', it can easily outrun the IKON.

Last edited by dhanushs : 31st August 2010 at 23:05.
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Old 1st September 2010, 15:13   #8
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Yes, punto does behave strangely, sometimes the acceleration is very smooth whereas sometimes it feels pretty sluggish. On some occasions it surprises me as i dont feel the need to downshift from 5th at as low as 40kmph.
Sometimes the car would reach an easy 165, whereas at times reaching 140 is a big struggle.

Anyone else experienced the same?
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Old 2nd September 2010, 00:37   #9
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It also depends on the ambient air temperature .
For eg at 25 degrees in morning or night with cold start you would definitely feel a better drivability than with a warm engine at 40degrees in afternoon.

But as others have said please do not enjoy the car much before optimal temp is reached .
I hope it is your own hard earned money car and you would not want to damage it .
Lubrication is needed in all things when they are rubbing along and even god made them so :-)

REGARDS

Last edited by Trust_In_Thrust : 2nd September 2010 at 00:41.
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Old 2nd September 2010, 01:39   #10
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Maybe too much of EGR??
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Old 2nd September 2010, 20:19   #11
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Quote:
Originally Posted by fink_ployd View Post
Hi,

When I start my car for the first time, i.e. when the engine is cold, my car performs much better than it does when the optimum temperature is reached. On the first start the engine revvs more freely, the engine noise is also significantly low and the car drives much faster.

Anyone else noticed the same, anyone knows the reason for the same?

I drive a fiat punto diesel

Thanks
The only reason I can think of is that the oil is a shade more viscous at start up and that suppresses some engine noise ; as you reach operating temperatures,the oil flows better but cannot conceal engine noise.

In ealier days when Fiats and Ambys were aplenty,I know of used car dealers using gear oil :engine oil in a certain ratio to suppress abnormal engine noise.
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Old 2nd September 2010, 20:41   #12
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My Scorpio behaves this way too, but it has done nearly a lakh kms, but the phenomenon is still not justified, IMO. My ASC as usual just says "do not worry saar, this is Scorpio. Scorpio is verrry good vehical (sic)". So your Punto has some company, to say the least.

Maybe this phenomenon happens if the engine has developed a lot of premature wear and tear, which means that the clearances between moving parts, bearing plays etc. increase further with increase in temperature, resulting in increased noise at higher / running temperatures (in case of worn out engines only).
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Old 2nd September 2010, 23:32   #13
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Quote:
Originally Posted by fink_ployd View Post
Sometimes the car would reach an easy 165, whereas at times reaching 140 is a big struggle.
Something definitely wrong here. I'd suspect an airflow or temperature sensor issue, or a sticky EGR valve (sticking when hot). Ask your service centre to run a scan - both when the engine is hot AND cold.
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Old 3rd September 2010, 23:12   #14
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I too can't really comprehend the good performance of the engine during 'cold' starts!

@fink_ployd, how long does your car behave like this? at what time do you start the vehicle?

My guess goes with the reduced ambient temperature which leads to higher density of air. Hence, more fresh turbo charged air is entering the cylinder. The temperature needle showing midway indicates a working engine temperature. Lower intake temperature means lower increase in air temperature after turbo charging, which means, the cylinder is getting a good amount of fresh air. Hence you get very nice response.
Also, the radiator is getting the same cool air hence keeping everything cool!

@Jomz, EGR doesn't improve engine performance from the torque and power perspective, especially in Diesel! Also, EGR comes into picture at higher temperatures for reducing NOx emissions in Diesels.
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Old 4th September 2010, 07:31   #15
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Quote:
Originally Posted by lambdaplus View Post

My guess goes with the reduced ambient temperature which leads to higher density of air. Hence, more fresh turbo charged air is entering the cylinder. The temperature needle showing midway indicates a working engine temperature. Lower intake temperature means lower increase in air temperature after turbo charging, which means, the cylinder is getting a good amount of fresh air. Hence you get very nice response.
Also, the radiator is getting the same cool air hence keeping everything cool!
Yes, im guessing the same thing as i have noticed it mostly in the mornings.
Uh, isn't it somewhat how a cold air intake works?
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