[SS-Traveller]

Originally Posted by sudev

Typical layout has fuel pump next to engine and hence the pipe from tank to the pump is actually under suction. From pump to injectors is pressure circuit and the over flow from injectors is "spilled" back to fuel tank through a pressure control valve.

Even in common rail circuits with the low pressure pump installed as a submerged unit in the tank (my Accent has that), the job of this pump is to prime the high pressure pump - while running, the high pressure pump sucks more fuel than the low pressure pump can push out, so the tank-to-high-pressure-pump line remains under suction, not under pressure. Overflow from the rail and injectors is not sent back to the tank, since the heated fuel would gradually heat up the fuel in the tank and cause evaporation, leading to environment pollution. Instead, this overflow is routed back to a point on the fuel line upstream of the high-pressure pump, feeding the heated fuel back to the circuit itself, and so...

The recirculation of "spill" diesel (does not) also warm up rest of the fuel in tank as it tends to carry heat from near the cylinder head (injectors) back through return circuit.

But it continues to provide warmed diesel to the rail and injectors.

Originally Posted by Roshun

...do you suppose adding an electric fuel pump just after the tank will maintain constant pressure at all times?

Yes and no. If the injectors are the culprit (which is Theory 1 and I support it first), no extra pump will sort out the problem. On the other hand, if a design fault exists in the low-pressure pump which is incapable of priming the high-pressure pump to allow it to start, an extra electric pump will indeed solve the issue.

Should this suggestion go back to M&M R&D, considering it looks like a common problem at high altitude?

But then, half the CRDe Scorpios run fine, so M&M would take this suggestion with a pinch of salt.

Originally Posted by anupmathur

Roshun, as said earlier, the taxi drivers at Leh use the non-CRDe Scorpios. They did not face any such problem with that vehicle.
They simply did not buy the CRDe!!
I am told this was one of the primary reasons behind the launch of the M2DI.

But that does not solve your (and Roshun's) problem at hand. And M2DI's are Euro-II, not Euro-III ready.

I am not saying that an electric fuel pump will not help. It might just do; I do not know yet.

But to solve the issue, we'd need to start somewhere - and cleaning the injectors is the easiest option. The extra pump can be installed any time later on.

[anupmathur]

Originally Posted by SS-Traveller

... - while running, the high pressure pump sucks more fuel than the low pressure pump can push out, so the tank-to-high-pressure-pump line remains under suction, not under pressure.

This is impossible! A feed pump will always have a throughput much greater than the injection pump will ever require. The feed pump has to maintain the ring main at a certain positive pressure; also to ensure that vapour lock does not occur easily, despite the elevated temperature in the ring main.

Originally Posted by SS-Traveller

But to solve the issue, we'd need to start somewhere - and cleaning the injectors is the easiest option. The extra pump can be installed any time later on.

Agreed! And after the cleaning, the only way to test will be to head for the hills!

[tsk1979]

I once had a faulty O ring in the indica(from hand primer). there was no diesel smell, but the fuel lines were drawing in air.

[anupmathur]

Originally Posted by tsk1979

I once had a faulty O ring in the indica(from hand primer). there was no diesel smell, but the fuel lines were drawing in air.

Understandable, since this is the suction line of the pump, to draw fuel from the tank.

[gd1418]

I went to Bombay in 2006 in my Safari of '98 vintage. When I broke journey at Udaipur for the night, I noticed a wet patch at the parking beneath the engine bay. I HATE leaks. This raised my BP and on opening the hood I saw that the fuel filter unit had signs of spillage. I cleaned it with cloth and then proceeded further to Bombay.

I stopped at Ankleshwar for a pit shop and when I opened the hood to check the leakage, I saw shining diesel on the fuel filter area. We ll I treid tightening the nuts but they are were all tight.

To cut the story short, after return from my trip I went to my FNG and on opening the fuel filter unit ti was noticed that both the "O: rings were frayed and damaged. Hence the leak.

I had installed an electric pump before undertaking this trip. My mechanic told me that but for this electric pump I would've got stranded as the fuel line would've taken air and starting the vehicle would be an issue.

[anupmathur]

Originally Posted by gd1418

I had installed an electric pump before undertaking this trip. My mechanic told me that but for this electric pump I would've got stranded as the fuel line would've taken air and starting the vehicle would be an issue.

GD, thanks for this input!
I'm keenly reading every suggestion and hoping that something will crystallize from it all!
Leaky O rings would have created a starting problem at EACH start.
As you can see, my problem is a bit different. ONLY the first start of the day at high altitudes has been an issue.
Any other ideas? I'd be grateful.

[Roshun]

Mandar, HVK, Glen,

I'm keen to know how your Scorps behave each morning at each location on your Ladakh trip. On our trip we had a fair bit of drama, but not with all the Scorps. So I'm trying to see if this problem is only model specific - the high-altitude starting problem. Is it better this time of the year? What are the temperatures like?

With the number of Scorps in your convoy, it will be a nice comparison to the four in our convoy earlier in the year.

Cheers,

[shankar.balan]

anup hi
yes the old non crde scorps were always better off in the high hills - less electronics to seize up and get jiggered.
thats why the M2Di vehicles are so popular in those parts.

Originally Posted by anupmathur

Roshun, as said earlier, the taxi drivers at Leh use the non-CRDe Scorpios. They did not face any such problem with that vehicle.
They simply did not buy the CRDe!!
I am told this was one of the primary reasons behind the launch of the M2DI.

I am not saying that an electric fuel pump will not help. It might just do; I do not know yet.

[hvkumar]

My non-crde performed magnificently in the high altitudes. No loss of power, pulled up effortlessly, most of the drive in 3rd and 4th gears except when it came to the steep hairpins. The only visible indicator of the high altitude being the black smoke. Mileage reported was normal.

[anupmathur]

Originally Posted by hvkumar

My non-crde performed magnificently in the high altitudes. No loss of power, pulled up effortlessly, most of the drive in 3rd and 4th gears except when it came to the steep hairpins. The only visible indicator of the high altitude being the black smoke. Mileage reported was normal.

Which is why I'd be more than willing to exchange my Scorpio with a non-CRDe 4WD!! Anyone?

[SS-Traveller]

Originally Posted by Roshun

Mandar, HVK, Glen,

I'm keen to know how your Scorps behave each morning at each location on your Ladakh trip. On our trip we had a fair bit of drama, but not with all the Scorps. So I'm trying to see if this problem is only model specific - the high-altitude starting problem. Is it better this time of the year? What are the temperatures like?

With the number of Scorps in your convoy, it will be a nice comparison to the four in our convoy earlier in the year.

Cheers,

No one except HVK volunteering the information?

And sen2009 had a cold starting issue on his Safari too, on the recent trip.

Also, just wondering - would this product be of any help? It's called FAST START® Starting Fluid, by Pidilite. Any one has an idea of how to use it and what it does?

[hvkumar]

We took a few precautions:
- Parked the car nose into the building or covered space to avoid direct wind in the engine area
- Sweatered the bonnet grille, I with newspapers and Glenn with gunny bags, such that the entire front open area was insulated against the cold
- In TsoMoriri, I parked the car in a slope (tip from Roshun)
- Started the car before going to sleep (this was Glenn's tactic)

In Padum, which was pretty cold (0 C I guess, maybe a little colder with the chill wind blowing), we started at second try

In Tangtse, it was no problem at all

We had serious problems at Karzok (TsoMoriri), where each of the Scorpios took 10-15 tries before the engine warmed up and fired. Each time we turned the ignition, we could hear the rumble, but the engine was too cold. We kept igniting in short bursts, and got the engine going without exhausting the battery.

[anupmathur]

Originally Posted by hvkumar

....
We had serious problems at Karzok (TsoMoriri), where each of the Scorpios took 10-15 tries before the engine warmed up and fired. ....

HVK, the problem is that the problem I've been having is not temperature related. Even at temperatures of 16 and 18°C morning start has been a problem at high altitudes!

BTW, what capacity battery is fitted in your Scorpio? Mine had come with a 65 AH which I have recently changed to 80 AH to allow for more cranks when on trips to the mountains.

[hvkumar]

Originally Posted by anupmathur

HVK, the problem is that the problem I've been having is not temperature related. Even at temperatures of 16 and 18°C morning start has been a problem at high altitudes!

BTW, what capacity battery is fitted in your Scorpio? Mine had come with a 65 AH which I have recently changed to 80 AH to allow for more cranks when on trips to the mountains.

I am now with 70 ah batteries. Happily, the batteries were all robust and took the long starting bouts.

[Styler]

It's time for Leh again this year. The advice here is very useful.

I am leaving with my family for Leh on the 6th of June from Delhi in a 2003 NON CRDE Scorpio.

I am compiling from this thread, a brief list of precautions which will minimize the risk of Starting Problems in the High Altitude.

Before you start :

1. Get Nozzles Serviced
If anybody has list of Service Centers where this can be done, it would be useful for all.

2. If possible Get a Electronic Fuel Pump installed before the Fuel Filter. GD Bhai do let us know what it entails to get this done.

3. Good Clean Air Filters and a Good Battery are essential.

During the Travels at the High Altitude

1. Park your Vehicle at a place which is enclosed a little, between tents, and if possible the Bonnet facing a Wall. Park at an incline with the Bonnet on the down side.

2. Insulate the front Grill with Newspapers / Rags / Boris / Whatever to prevent the Cold Winds getting into the engine area.

3. Run the Engine for a little while before going to sleep.

4. Turn the Ignition, wait for 10 secs, do a small prayer and do small burst at the self.
If the engine does not fire up, wait for 10 secs, and repeat.

4. If the Engine still doesn't start, manual pumping of the pump would help.


Seniors please add or correct any of the Information mentioned above.

Also GD recommends For non-CRDes that are without the ECUs, please disconnect the EGR valve after you cross Rohtang. Does anybody have pictures for this. Can somebody describe in detail about where the EGR Valve is and how it is disconnected.

Styler