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-   -   Common Rail : Why is cold start tougher at higher altitudes (https://www.team-bhp.com/forum/technical-stuff/85817-common-rail-why-cold-start-tougher-higher-altitudes-3.html)

Can you update more SS! Where did you buy it form? Whats the expiry date. It sounds like a good thing to keep in the vehicle for the mountain trips

SST saab,

time to head out into the hills now :D
or hand it to our resident mountain champ tanveer for his regular sojourns!!

:) Updated directly.
Not now - my holiday plans have been cancelled/postponed; waiting for December-January.

Highest altitude where the Scorpio mHawk engine was started by me, was at Korzok (Tso Moriri) on 15 June 2011 - altitude close to 15,000 feet. Engine started at 6 AM after overnight parking in open (no precautions or blankets etc.). The minimum temperature readout on the thermometer inside the car showed (+)1.5*C. No diesel gelling had occurred - stored cans of diesel in the back of the car were quite fluid. Diesel in the tank was treated with BG247 additive @1ml/litre approximately.


Starting results: Engine fired with one long 5-to-7-second crank, emitted one puff of light smoke, and settled into normal idling.

That is surprising :D. Did you notice any change in power delivery? Overall, how was the drive-ability along high altitudes?

Spike

:confused: What is surprising?

Driveability and power delivery were quite fine, except on the way to Khardung La (18,380 feet), the first time we reached above 16,000 feet. Felt as if I had a choked air filter, the engine was refusing to rev freely. The engine check light lit up too for about 15-20 minutes, then went off on its own. On the way back across K'La again, I thought the engine was responding much better. Did not feel a power drop or choking of engine when going across Chang La the next day, or any of the other passes above 16,000 feet subsequently.

Got the engine check light 3 times in all during the trip, with no rev limitation or any other driveability problem. All times, it was during sharp climbs. So what was happening? Did the ECM re-program itself or something?

So the additive really works! I think the real test of such an additive would be in october, when temperatures drop below -5 degrees early morning.

Though I did not faced this issue with my Petrol SX4 at -4 in Hanle last Year. It started in one crank.

But I am not sure if this can happen with petrol cars as well. Do we have to cover the bonnet area for petrol cars also?

Petrol does not freeze / gel at temperatures that human beings can generally withstand, so don't worry about it!

Diesel sold at high altitudes has anti-freeze added to it. If you are tanking up in Ladakh, there is no need to add any other anti-freeze to your fuel.

When I was in Ladakh 2 years ago, I only came across M2DI Scorpio taxis. Apparently, the CRDe has issues in those altitudes. Perhaps Spike can confirm this (or may be it would be inappropriate for him to do so :-p) but one of the reasons why M&M did not discontinue the M2DI Scorpio was because the taxi operators in the hills were not buying the CRDes in any decent numbers.

Diesel sold in ladakh does not have anti freeze added.
Only army stock has antifreeze.
I think in winters they may add anti freeze, but summer diesel only has kerosene and naptha adulteration in dollops.

A local Innova taxi driver in Spiti told me that they add about 2 liters of Petrol in a full tank of Diesel during December-January at Kaza.

How is it different from adding Kerosene with respect to lubricating characteristics and wear & tear?

I recently had to start the safari on a cold morning at 2500mts
Temperature was -7 degree c, and overnight it went below -8

I had parked the vehicle around 5pm the previous evening when the temperature was -2 degrees.
The vehicle started at first crank. Diesel was from plains(no anti freeze).
I did not even need to give a long crank.

In Hanle(4500mts) even with min temp not going below -2/-3, and morning temp being 5+, starting was a big issue.

Thanks for the reminder TSK. Yes I was following the thread very closely. But the time when the thread was on my account on BHP was put under restriction because I had a few one liners.

I have followed your observation very closely and had came to conclusion that the only cause is due to wax formation inside the fuel filter and fuel pipes. You have yourself mentioned that you had felt the rubber bulb pump to be quite easy when you pumped for the first time. This itself indicates that there is no liquid fuel in it.

Now the question which really is making rounds in my mind is why did your vehicle start at lower temperature at lower altitude but did not start at higher temperature & higher altitude ?

The ecu has a atmospheric pressure sensor which is in built. But i dont think it could have sensed any wrong reading or like that.

Do you remember how much quantity of diesel you had in your tank in both the cases. You are stating that you had the same diesel as used in plains( I assume you have not topped up your tank after you left the plains)

I mean less quantity of diesel took less time to freeze or wax.

Keep us updated this is really a intresting thread and has many things to learn.

Regards

Samir

In the -8 2500mts scenario, I had approx 50 liters in tank. In Hanle also(4500 mts), I had around 40 liters in tank. Definitely more than half.
And this observation is observed many times.
Whether its Tangste(4100mts), hanle(4500mts), the vehicle takes more effort to start, however at 2500mts, even at sub zero start is easy.

At hanle, in 2010, I could not start after 5-6 tries. I pressed rubber bulb till it got hard, and kept trying.
After that I pushed vehicle in sun, with left side (with fuel tank) towards sun. After 15 minutes of sun bathing, start happened, but she idled for 2 minutes at 400-500rpm. Engine kept trying to stall. After around 5 minutes the idle stabilized to normal value.

Could it be because of higher water content in the diesel available in leh? If diesel had been adulterated with kerosene, I presume starting should have been easier.