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Do a search on idle or idling. There are some who say that letting it idle below 1000 rpm will cause "wet stacking". Do a search on that. When it is really cold (30 degrees here in central Texas is really cold). I let mine idle for 5 - 10 minutes at the most.
I performed that search and only found references to the subject. No info on what it is, how it is caused (extended idling I assume), what it does to the motor, how much it costs to fix, or how many people have had the problem.
Wet stacking is basically where the fuel doesn't completely combust (because of the cold engine) and condenses on the walls of the cylinders. This is mostly going to happen at low idle in cold weather, where the efficiency of a diesel that's not doing any work is so high that the engine never really heats up.
The fuel can wash down into the crankcase over time, which is bad. The fuel can also coke up the upper cylinder and the valve guides. That's bad too, but supposedly a good hard run at temperature will clear most of that out again.
5-10 minute idling isn't going to kill you. If you need to let it idle for extremely long periods of time, then you should really get something to boost the idle, anything from an AIC to a broomstick handle to prop against the pedal.
Having said that, on any car but especially on a diesel (that doesn't make heat until it does some work) your best strategy on a cold start is to get the truck moving down the road right away, simply taking it easy with the RPMs until it's warmed up a bit. No need, and very little benefit, from letting it just sit and idle.
I'm pretty sure the computer will boost the idle for you from base to around 1100 RPMs if you let it sit long enough. I know it has a cold kicker on it. I've got a Feb 04 Engine with its original flash.
Yes, the cold weather strategy will boost the idle, but there are some who say that it doesn't boost it high enough (based on reading their EGTs when it does it.) Better than nothing though I guess.
It has been a year here since cold weather and I park mine in the garage. So I can't tell if it idles up when cold. I wanted to know if it still does it with the new flash.
Startup when cold is definitely different. It almost has the BRAAAP sound it used to make when I first bought it and it had pilot injection.
Yeah it still idles up after the new flash, and starting cold (she sits outside) is painful and I have no access to an outlet. It starts off real loud, speeds up to 900 after a minute or so and then goes to 800, 700, and 600 when warm.
It has been a year here since cold weather and I park mine in the garage. So I can't tell if it idles up when cold. I wanted to know if it still does it with the new flash.
Yep...I had my truck reflashed last month...it will up the RPMs when its cold to about 900 until I hit the brake then it will drop down to normal.
Concerning the "Wet Stacking" issue...I'm not so sure about just letting it idle for 2min then driving slow. I used to let it idle for about 10min...the temp guage would generally be just above "cold", then I would take it easy (below 2000rpms) until the guage was mid hash mark....no issues
I played around with the 2min warmup and found that upon intitial acceleration (real slow) I would get a small "chatter" at about 750 rpms. This of course would disappear completely once the engine was warmed up. Sounds like I need to loosen and retighten the downpipe...cause thats what I think it is now.
The question that still concerns me is the possibility of a Turbo Pedistal issue if the hanger in question is not the culprit. Since I have never experienced "Turbo Drone", I'm not sure if it sounds like what I described above. If it does and is the Turbo Pedistal then, my experience above indicates that a cold engine aggrivates it.
Thoughts?
Last edited by Bear Hunter; Dec 8, 2004 at 12:54 PM.
Mine sounds and acts the same when cold. This tank I have been trying a 5-10 minute warm-up and <2000rpm until mid-hash marks. My mpg should go way up due to the decreased idling time).
Operating temperature is crucial to diesels because the block is so thick and all the parts, pistons, rings, crank, etc. are so heavy duty. They are all made of different materials and have varying sizes, so until all the metals expand (each at a different rate) to the point in which they are designed, the thing runs rough.