4720 fast idle

[birchbark]

I have a 4720 and when the ambient temperature is cooler, not exactly sure at what temperature, even though the engine is warm , when you start it the engine goes to fast idle for a while then slowly idles down..does anyone know how to stop this from happening? There must be a temperature sensor somewhere that can be bypassed or possibly moved to another location that may sense a higher temperature? It痴 quite annoying and uses more fuel than necessary.. thanks

 

[oosik]

This feature is probably designed into the operating system. I would suggest that you learn to live with it.

 

[kennyd]

Normal...don't second guess engineers.

 

[Beaver Cove Deere]

This feature is probably designed into the operating system. I would suggest that you learn to live with it.

Annoying? Absolutely, but I'm not sure tinkering with the onboard computer is worth the potential hassle.

I had two bosses that would have kicked me to the curb running an ice cold diesel at 1500RPM's during start up or within the first 5 minutes.

 

[birchbark]

Annoying? Absolutely, but I'm not sure tinkering with the onboard computer is worth the potential hassle.

I had two bosses that would have kicked me to the curb running an ice cold diesel at 1500RPM's during start up or within the first 5 minutes.

Yes I get it but totally unnecessary.. I was hoping someone might know where the sensor is located .. I would move it or jumper it somehow. I worked with sensors and thermistors for 30 years so very capable if I could find its location.. there has to be a sensor somewhere that measures ambient temperature

 

[ptsg]

Yes I get it but totally unnecessary.. I was hoping someone might know where the sensor is located .. I would move it or jumper it somehow. I worked with sensors and thermistors for 30 years so very capable if I could find its location.. there has to be a sensor somewhere that measures ambient temperature

Probably there is a sensor but that sensor may also send signal to the glow plug timer so it adjusts the time the glow plug turns on accordingly to the coolant temp.

 

[dadiehl]

My JD 3320 did it. I never had so much as one problem with that machine. Sold it with 600 hours. My Kubota M7060 does it. I just assume god intended it this way. If it’s really cold I run my bullet under the machine for about 45 minutes in the shed. After that it does not do it when I start it.

 

[jenkinsph]

As I remember reading that the low idle speed is more damaging causes more vibration than the fast idle. Also less likely to build up internal deposits and faster warm up. I am not an engineer but I notice that most engines today have this same feature. Must be a common agreement that it is worthwhile. I agree with others to leave it alone and enjoy your tractor.

 

[RoyJackson]

I had a 4520, now a 4052R..
Once I start the engine and oil pressure is normal, I always increase RPM to 1500 or so.
Diesel at slow idle don't heat up and wet stacking can result.

The 4052 is my 5th Deere...I've followed the same starting procedure on all of them

 

[Bavarian]

The bigger tractors do the same. They usually use coolant temperature for glow plug and high idle.
IIRC, the manual says, once the engine speed drops down to normal RPM, it's ready to go. And that's long before any temp would show on the gauge.

And I still don't rev it up past 1700 during the first few minutes after that.

 

[RoyJackson]

The bigger tractors do the same. They usually use coolant temperature for glow plug and high idle.
IIRC, the manual says, once the engine speed drops down to normal RPM, it's ready to go. And that's long before any temp would show on the gauge.

And I still don't rev it up past 1700 during the first few minutes after that.

Personally, I don't go to PTO RPM until the temperature gage starts indicating warm up. If I don't need the PTO, I'll start work after 5-10 minutes of fast (1500 RPM) idle

 

[birchbark]

The bigger tractors do the same. They usually use coolant temperature for glow plug and high idle.
IIRC, the manual says, once the engine speed drops down to normal RPM, it's ready to go. And that's long before any temp would show on the gauge.

And I still don't rev it up past 1700 during the first few minutes after that.

Ok guys and girls, I believe youæ±*e not understanding my issue. So letç—´ say itç—´-10c outside, tractor has been running for an hour and is at full operating temperature.. I turn it off for 2 minutes..I go to start it up and it goes to fast idle immediately..and stays there for a while.. just a pain in the *** and totally unnecessary. Thatç—´ the issue

 

[jd110]

I looked through all of the engine electronic control information. It does not say any exact parameter the computer is looking at to control idle speed. It only states that intake manifold air temp, coolant temp, fuel temp, turbo temps, exhaust temps, manifold air pressure sensor, and even temperature sensor internally in computer are all used to determine fuel settings. Tampering with how it interprets these readings will likely result in error codes and derating under some operating conditions.

 

[Bavarian]

Ok guys and girls, I believe youæ±*e not understanding my issue. So letç—´ say itç—´-10c outside, tractor has been running for an hour and is at full operating temperature.. I turn it off for 2 minutes..I go to start it up and it goes to fast idle immediately..and stays there for a while.. just a pain in the *** and totally unnecessary. Thatç—´ the issue

That's a whole different situation. Something definitely hung up in the electronics. It would be interesting if a computer could read the real time sensor signals when it's doing it. I don't know if a diagnosis software exists that works that way.

 

[dadiehl]

Green tractor talk has this conversation started 2/28/15. Someone on there explains where the sensor is. For the life of me I can’t get that post to copy and send it here. The posts title is 3 cylinder yanmar cold idle speed.

 

[Bavarian]

I took a screen shot. I got right there after I typed in the search on Google.

 

[beenthere]

That is pretty clear that the fast idle is intentional.. now will birchbark try to disable that feature?

 

[Bavarian]

I think his problem might be in the IP itself.

 

[jd110]

The 4720 does not have a Yanmar engine. It has a 4024 JD engine. It has 4 individual unit pumps and not one pump for all cylinders. Probably works off of same principal though.