Team-BHP - Tata Tiago : Official Review

Quick question, since i don't have the owners manual, is there any specific method mentioned to do a cold start? Do you wait for the glow plug light to go OFF before cranking the engine? Next time while doing a cold start switch ON and OFF the ignition (don't crank the engine) 2 or 3 times so that the heater plug works and heats the combustion chamber.
Since it's a cold start issue, chances are the glow plugs or the glow plug module mite not be working the way it should.

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Originally Posted by rakesh_r (Post 4228048)

You ALWAYS wait for the glow plug light to go off before cranking the engine. It is a most basic and fundamental thing. Also, it is a best practice to let the heater plugs run a couple of times before starting the engine when the weather is cold.

Quote:

Originally Posted by rakesh_r (Post 4228048)

Usually in cold especially for diesel specific vehicle it is advisable to pre-heat the plugs 2-3 times before initial start. I follow it. If you see the video, the 2nd and 3rd vehicles were preheated 3-4 times before ignition. Yes, even i suspect the glow plugs might be the issue here. Its very strange that its happening in new vehicles :Frustrati. I still own diesel indica which cranks in single start even in cold conditions.

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Originally Posted by Shreyans_Jain (Post 4228053)

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Originally Posted by supramani (Post 4228064)

I couldn't see the video, apologies for that. My experience with driving Diesels since 10 years, I always wait for the Glow Plugs to switch OFF before starting the engine.Though the glow plugs in modern crdi engines hardly stay ON for a fraction of second. Get the glow plug module and the plugs checked from TASS or a reputed Bosch service centre( I presume Tiago has Bosch or is it Delphi).

There might be a simpler solution in cold climate: Add high Cetane diesel in cold places. I noticed a slight increase NVH levels in my diesel engines whenever I was in Ooty. I filled up in ooty once and from the next day, things returned to normal.

Now the technical part:
When a cold diesel engine is started the heat of compression is the only energy source available to heat the fuel in the combustion chamber to a temperature that will initiate the spontaneous combustion of the fuel 400°C. Since the walls of the combustion chamber are initially at ambient temperature rather than operating temperature, they act as a heat sink rather than a heat source. And since cranking speed is slower than operating speed because of battery and added viscosity of the engine oil, compression is also slower, which allows more time for the compressed air to lose heat to the chamber walls.
As the compression temperature is reduced by variables like lower compression pressure, lower ambient temperature, and lower coolant temperature, an engine requires an increasingly higher cetane number fuel to start easily. Research indicates that fuels meeting the ASTM Standard Specification D 975 cetane number requirement of a minimum of 40 provide adequate cold starting performance in modern diesel engines. At temperatures below freezing, starting aids may be necessary regardless of the cetane number of the fuel. Even after the engine has started, the temperatures in the combustion chamber may still be too low to induce complete combustion of the injected fuel.

The resulting unburnt and partially burnt fuel is exhausted as a mist of small droplets that is seen as white smoke. This situation normally lasts for less than a minute, but the exhaust is irritating to the eyes. A fuel with a higher cetane number can ameliorate the problem by shortening the time during which unburnt fuel is emitted.

Quote:

Originally Posted by rakesh_r (Post 4228071)

I couldn't see the video, apologies for that. My experience with driving Diesels for last 10 years, I always wait for the Glow Plugs to switch OFF before starting the engine.Though the glow plugs in modern crdi engines hardly stay ON for a fraction of second. Get the glow plug module and the plugs checked from TASS or a reputed Bosch service centre( I presume Tiago has Bosch or is it Delphi).

Yes, the issue might be with the glow plugs. Here all the three vehicles stated here has the same issue. Probably, some issue with the first batch of vehicles dispatched(All are may - August 2016 make). I have mailed to Tata regarding the same. lets see what Tata has to say regarding this.

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Originally Posted by supramani (Post 4228075)

Might be the glow plugs, yes. But does Wayanad get that cold in the first place? I mean, so many Tiagos are sold here in Delhi and Punjab. Winters here are well and truly cold. Never heard of any Tiago having this kind of a problem

I was browsing through the internet regarding this issue of white smoke in Tiago. Interestingly in the below video, it is the exact same problem that all the three vehicles stated are experiencing now. The below video was uploaded by a owner a year back stating that he has the problem with the new diesel engine.

https://youtu.be/dOiEzCifBW0

Probably thats a common issue that is still prevailing only in hilly regions and the smoke vanishes once it has reached the optimum temperature.

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Originally Posted by a4anurag (Post 4228522)

Hey, just got a thought in my mind, can you disconnect the MAF sensor and see if there is any change or no in this smoking pattern? I mean when engine is cold.

Yeah , I do it and see if it smokes again. The only catch is it happens only in hill stations in morning start. I live in Chennai , where the climate is normally hot and there are no symptoms. Probably I have to go for trip now .