Elevation = rough start up..?

[Snobdds]

Diesels do not throttle the air like a gas engine. There should be no noticeable difference between the two altitudes.

You have to run more RPM at altitude for the same power...

 

[SPYDERLK]

Anybody here know anything about diesels at altitude, and with and w/o turbo speak up please.

 

[the old grind]

Just like how a turbo gives more power without more fuel, or how diesels make so much more smoke at altitude for lack of air.

(not to get technical, but I was just warming up... )

 

[SPYDERLK]

The air cleaner on all my diesels keep the butterflies out.

 

[puzlrock]

When it gets cold in Montana I plug in the tank heater, starts and runs great.

 

[DutchInNZ]

Ummmm, pretty sure that's not how math works to get a percentage.

"Air" is also a dangerous assumption. "Air" doesn't cause ignition it's the O2 in the air.

For partial pressure O2 at sea level it's ~20.9 at ~14.7PSI, going to 3,200' it's just less than ~2 PSI lost (about 1.8), so (1.8PSI/14.7PSI)*20.9 PPO2=~2.55PPO2.

So loosing ~2.55PPO2 from sea level that's ~2.55PPO2/20.9PPO2= 12.2% loss of O2 per volume.

Carry on.

etpm is right; that is the diesel physics. A diesel gets to its ignition temperature by adiabatic compression of air to bring it to a high temperature, after which fuel is injected that then burns with the oxygen. Less air in = lower compression = lower temperature, so no ignition or bad irregular burning, which makes the typical diesel knocking sound until the engine is warm.

 

[DutchInNZ]

And it is all dependent on the burning of fuel. Air volume per revolution is the same except in turbo equipped engines where boost has developed.

Less air pressure in equals less volume of air in equals less pressure at TDP equals lower adiabatic ignition temperature equals bad starting when cold.

My Zetor, as all of the old series, does not have glow plugs but a very high compression ratio that makes for problem-less starting.

 

[SPYDERLK]

Filters changed at 48 engine hours in Oregon. Problem started immediately upon arrival in Idaho. Temps in June at start up were in 50˙ range, yesterday 28˙....

It is to be expected with the thinner air and consequently lower compression heat. There will also be a slight?probably unnoticeable loss of power even when warmed because each lungful is a little less air than at sea level. At full load there is more likely to be an excess fuel condition - exceeding the amt burnable in the slightly air starved condition.

A turbo equipped engine will see the same startup issue, but then will pretty quickly come up to a wholly undiminished power capability as the cylinders warm and exhaust heat and boost develops.

 

[JasperFrank]

Interesting reading glow plug times of more than 5 seconds. 15 Seconds? Sat with my stop watch and timed out 15 seconds. I have never held the glow plugs on for more than 5 seconds. 1200 feet, very small 1 liter engine and garage rarely gets below freezing. Wonder if excessive use of glow plugs is in anyway harmful to the engine? What are the recommended glow plug times for larger tractors?

 

[SPYDERLK]

Interesting reading glow plug times of more than 5 seconds. 15 Seconds? Sat with my stop watch and timed out 15 seconds. I have never held the glow plugs on for more than 5 seconds. 1200 feet, very small 1 liter engine and garage rarely gets below freezing. Wonder if excessive use of glow plugs is in anyway harmful to the engine? What are the recommended glow plug times for larger tractors?

Only harmful to the glowplug.

 

[sea2summit]

etpm is right; that is the diesel physics. A diesel gets to its ignition temperature by adiabatic compression of air to bring it to a high temperature, after which fuel is injected that then burns with the oxygen. Less air in = lower compression = lower temperature, so no ignition or bad irregular burning, which makes the typical diesel knocking sound until the engine is warm.

Don’t go messing logic with my math

You are correct, I know better than that.

 

[sea2summit]

Interesting reading glow plug times of more than 5 seconds. 15 Seconds? Sat with my stop watch and timed out 15 seconds. I have never held the glow plugs on for more than 5 seconds. 1200 feet, very small 1 liter engine and garage rarely gets below freezing. Wonder if excessive use of glow plugs is in anyway harmful to the engine? What are the recommended glow plug times for larger tractors?

Glow plugs continue to stay hot I believe, I don’t think the igniting diesel burns cooler than they are?

 

[PILOON]

I have needed to heat my plugs a few times in cold weather, often twice and occasionally 3 X.
My timer clack's B4 re setting so I know when to re glow. But then I have always started.
Generally I re glow if my CUT wont fire up after about 10 or so RPM's.
Now my CUT is a '58 with 1800 hrs and still doing all that I ask of it.
My take is cold starting was not then what it is today and so far nothing has hurt my CUt from my procedures.
One thing I do is have an intelligent battery tender permanently attached so I always have a full charge.

 

[SPYDERLK]

I have needed to heat my plugs a few times in cold weather, often twice and occasionally 3 X.
My timer clack's B4 re setting so I know when to re glow. But then I have always started.
Generally I re glow if my CUT wont fire up after about 10 or so RPM's.
Now my CUT is a '58 with 1800 hrs and still doing all that I ask of it.
My take is cold starting was not then what it is today and so far nothing has hurt my CUt from my procedures.

[[ One thing I do is have an intelligent battery tender permanently attached so I always have a full charge. ]]

Good cranking speed is a plus with cold cylinder walls!

 

[Gnome]

Figured out how to upload video to this forum. Started my LS mid day yesterday, temperature about 48˙, elevation 3,000', 20 seconds on the glow plugs. This tractor never started this rough with so much smoke when at sea level at similar temperatures. But, it does smooth out. Just rougher than a cob at first light....

 

[CobyRupert]

I think the white smoke means fuel is not being burnt properly. But why?
It is smoke, and not vapor, not anti-freeze right? No sweet smell and no coolant loss from reservoir tank?
So why is fuel not burning? Too much fuel? Is this a common rail injection system? Bad injector? Or does a cylinder have low compression that doesn’t ignite fuel at initial low temps?

 

[Cameron Smith]

You have a cylinder that is not firing until the others ARE and helping it catch up. I would first check my injectors and the valve settings. With such low hours, I doubt that compression is the problem.

 

[the old grind]

Bad injector as mentioned wouldn't surprise me. An uneven vs conical spray pattern might be less apparent at op temp than when starting. How's o'all power once it's warmed up?

 

[DieselBound]

How long to operate GPs depends on what the manufacturer says!

My cars (VW TDIs), truck (12v Cummins) and Kioti automatically controls how long the GPs (or in the case of the Cummins, heater grid) is energized to full. I know that in my VWs the GPs will continue to glow post ignition to help smoothen out things; not sure of the others.

My B7800 is purely mechanically operated. I don't remember the recommended time for operating the GPs on it; I just keep keying it until it starts up. On my generator (alsways seem to have a digital copy of its manuals around me), which is an early 90s Onan with a Kubota engine, the Operator's Manual says 10 to 30 seconds. Cycle time pretty much depends on how much current the GPs are pulling (and, of course, the rating on the wiring!).

Lack of combustion heat leads to the harder starts. More heat is required. Either coolant heater or more GP function. If this were my issue I'd be double-checking the GPs before anything else; and, I'd look at what the manual says for how long one can operate the GPs (and operate on the longer side). Every diesel is going to be a bit rough when firing up when its cold: my Kioti is really great at starting and running, but even it will be a bit less so just after a first start in the cold [and I'm not really in all that cold of a climate]). And as has also been noted, oil viscosity can also affect things: you want the fasted spin of the crank as you can get; oil rated for lower temps will provide that. Oh, and that also brings up the notion of the state of one's starter! I've pulled, cleaned and lubed many starters and that will go a long way to ensuring they operate as best as possible: ones operating in a clutched environment are susceptible to clutch dust and get a bit stiff. Good battery, good starter, good GPs and ample GP operation is one's best bet.

Lastly, weak injection pumps, bad fuel lines/filter connections and or injectors will also make starting tougher. But this starts getting away from the low-hanging fruit stuff!

 

[Gnome]

Bad injector as mentioned wouldn't surprise me. An uneven vs conical spray pattern might be less apparent at op temp than when starting. How's o'all power once it's warmed up?

Power and function is all normal and good once warmed up. Gonna check ejectors when I get a chance in a couple weeks.