What's it doing?

[tillboy2001]

What\'s it doing?

Ok, temp was about 7 degrees. A little warmer the last time it happened. On the new 4120 we have, I noticed a few times where the engine got unusually quite (much less pinging diesel sound). When this happened, it also smoked more than usual and stuck really bad. What's it doing? It does seem to have a little less power when this happens, but I wasn't doing heavy work so I'm not sure exactly.

Also, when should I worry about the outside temp and the diesel fuel? Any time that it most certainly should be treated with something for cold weather? It's not like I plan on using the tractor when it's below 20 F, but there are times like today when I need to use it to clear snow. Thanks

 

[Bob_Skurka]

Re: What\'s it doing?

Worry about your fuel beginning to gel when the temps hit the teens and below. Any of the commercially available anti-gels will work for you, a little goes a long way. Most are available in 12 oz to 32 oz bottles. Even a small bottle will typically treat 30+ gallons of fuel.

As for what your tractor is doing now to belch out excessive smoke and stink, I'm not really sure, but for a starting point I'd take a look at your fuel filter to see if there is any wax in there or if there is anything to indicate dirty fuel.

 

[JayC]

Re: What\'s it doing?

I remember reading the online manual for the 4000 Twenty series and it sounds normal to do that when starting it up when cold. Here's a quote from the manual:

<font color="green"> NOTE: It is normal for the engine to be louder and for blue-white exhaust smoke to be present during engine warm-up. The amount of exhaust smoke depends on air temperature. </font>

 

[tillboy2001]

Re: What\'s it doing?

Correct - it certainly does smoke a lot when you first start it. But this is after it's warmed up and maybe after using it for 20 minutes or more. It's as if the engine gets very quiet like a gas engine, makes more smoke, stinks...and then returns to the normal diesel pinging sound and feels stronger when it returns to the normal sounds. I know that doesn't sound very technical, but that's what it's doing...lol I was looking at the manual as well and this part from the troubleshooting section seems to match my situation more than any other condition I've seen in the book:

IF:
Engine Emits White Smoke

CHECK:
- Improper type of fuel.
- Low engine temperature.
- Defective thermostat. See your John Deere Dealer.
- Faulty cold advance device.

I buy diesel at the pump (BP, Shell, whatever is convenient)

I could possibly see the low engine temp being the issue. While I might be using it for a bit, I've noticed this happen when it was very cold out and sometime within the first 30 minutes of operation. I was doing some loader work today, clearing small shrubs and sapplings. It was maybe 20 degrees out and it didn't do it at all. Ran great. I guess it's maybe just the cold and nothing to worry about. I'll keep an eye on it.

By the way, getting used to the loader is a little trcky at first - if you want to work quick and look like you know what you're doing. I've bounced the front of the tractor off the ground quite a few times when lowering the bucket too far while scraping the ground...LOL Oh well, guess you gotta use it a few times before you look like the pros. After about 20 minutes or so, I was doing pretty good. I still have trouble judging just how far to lower the bucket before it digs in to far. Like I said though, after awhile I was doing pretty good and I've got a few crappy areas in the field cleaned up and smoothed off so it can be mowed easily /forums/images/graemlins/smile.gif

 

[BGL990]

Re: What\'s it doing?

Sounds pretty similar to what my 990 does.

When it's really hot out, startup is as you might expect - some smoke, quick warmup, everything sounds "normal" for a diesel.

When the temperature is cooler (down to around freezing or a bit below), the engine is definitely quieter and smoother sounding - more like a gas engine as you said. It also smokes quite a bit. After 5 or 10 minutes it warms up, the smoke diminishes, and the characteristic diesel knock returns.

When it is really cold, I use the intake pre-heater of course and aside from an initial puff of black smoke, there is actually less smoke than a warmer start - for a while. During this period the engine knocks and clatters like a diesel normally does. It seems like perhaps the intake pre-heater is actually kept on until the engine warms a bit because after a few minutes there is a sudden change. The idle speed drops a bit, the engine gets quiet and smooth and white smoke starts pouring out - just like the cool-but-not-too-cold start condition. I suspect this is when the pre-heater gets shut off. After a while longer everything warms up to operating temp and the noise and smoke return to normal.

In my case this whole process usually doesn't take 20 minutes (unles it's 20 or 30 below) but I wonder if the mechanism is similar in your case. That is, the engine temperature causing the difference in sound and smoke output. This may be grasping at straws, but I wonder if it takes 20 minutes for everything to warm up enough to open the thermostat. Up until then there is very little coolant circulation and the engine could be fairly warm and operating more or less normally. When the thermostat opens there may be a sudden cooling of the engine, resulting in the described symptoms until it all warms up again.

Like I said, grasping at straws, but maybe ....

In any event, I wouldn't worry about it too much.