CAT engine idling

[WIDGET33]

I know a lot has been said about not letting a diesel engine idle for more than 5 or 10 minutes, but a mechanic just showed me a way to raise engine rpm and set it and he claims if the rpm is around 1200 it does not hurt the engine to idle. He showed me how to raise it temporarily by holding the ACCEL switch on the cruise control until the rpm gets to where you want it. It will then hold that until you switch it off or step on the brake. Is this designed for this or does that hurt the cruise control?

 

[Grumpyyyy]

It won't hurt anything ... Thats what we do to operate our PTO systems on all of our work trucks

 

[FIRE UP]

WIDGET33,
I don't know what kind of coach you have, you didn't say. So, in my Itasca Owners manual, it tells all about using the cruise control for stepping up the idle. Obviously it has no detrimental effect on the cruise since the factory put it in the manual. What's kind odd though is, the manual actually states to turn the cruise on and push on the "Set" button to step up the idle.

Well, that's just a bit off. If you look at just about any cruise control, on any vehicle manufactured, here or abroad, the cruise has basically three switches.

1. On-Off
2. Set-Slower
3. Resume-Accel

So, if you reason things out, in our diesel rigs, you must push the "Res or Accel" in order to step up the idle. At least it's that way in mine. You can push the "Set" button all day long and it won't do a thing for the idle. But, push the Res and it will go up a certain increment each time you press it or, simply press and hold it 'till you reach the desired RPM. Now, if you've set it at your desired RPM and you determine that it's too high, simply press the set switch (just like you'd do to slow your car, M/H, etc.) and it well start to bring the RPM down until you let go of that switch.
Scott

 

[cbeierl]

On mine you can use the accelerator pedal to set the RPM you want and then the SET button will hold hit.

 

[AFChap]

On the Smart Steering Wheel (which I believe all modern Winnie diesels have) you simply press "on", then "set", and the engine rpm goes to 1k or slightly over ...that is what the manual says, and is exactly how mine works. And since the Smart Steering Wheel does not erase previous settings from memory when the key is turned off, pressing "Res" should also work.

 

[FIRE UP]

On the Smart Steering Wheel (which I believe all modern Winnie diesels have) you simply press "on", then "set", and the engine rpm goes to 1k or slightly over ...that is what the manual says, and is exactly how mine works. And since the Smart Steering Wheel does not erase previous settings from memory when the key is turned off, pressing "Res" should also work.

AFChap,
I do have the "Smart Wheel" and no, not all Winnies have them. We looked at quite a few that didn't. It was a requirement for me when we were looking. And, as far as the manual for our Itasca is concerned, yes it does say to push the "Set" to step up the idle. But, as stated earlier, that information is incorrect in that manual. Also as stated, I can hold on my "set" button for as long as I want and, my idle will stay at idle. If I push on the Accel/Resume button, it will start to climb and sit where I let go of it.

So, if your "Set" button steps up the idle, than it's opposite of mine. And since the set button is normally associated with: Set at present speed or, slow to a desired speed when held, I'm not sure how it works to increase idle. But, I'm certainly no expert on all of this. I just know how mine works. That procedure is the exact same on my sons Chev Z-71 pickup, our brand new Honda CRV, my Honda Goldwing GL 1800 motorcycle too. The difference of course is the fact that on those vehicles/motorcycles, the idle will not increase when any button is pushed.

You see, if yours works the way you're saying it does, then pushing the set button will also increase speed in the coach while driving, correct? And normally pushing the Accel/Resume button and holding it is used for increasing speed while driving. I'm not doubting you, I'm just wondering here why there would be two opposite operating characteristics on the same basic chassis/Smart Wheel.
Scott

 

[f14av8r]

I know a lot has been said about not letting a diesel engine idle for more than 5 or 10 minutes, but a mechanic just showed me a way to raise engine rpm and set it and he claims if the rpm is around 1200 it does not hurt the engine to idle. He showed me how to raise it temporarily by holding the ACCEL switch on the cruise control until the rpm gets to where you want it. It will then hold that until you switch it off or step on the brake. Is this designed for this or does that hurt the cruise control?

Please don't take this the wrong way. I'm honestly curious. Why do you want to idle your coach for extended periods?

 

[FIRE UP]

f1,
No one's taking you wrong on this. It's a perfectly logical question. We're not really talking about idling for extended periods of time. It's more about idling at a higher RPM for the time you do idle it. It is recommended to "up the idle" even for a short time to increase oil flow and cooling. It's just easier to do it with the cruise control buttons because it allows for you to go do other tasks while getting ready for departure and putting the coach in "Store" mode etc and, still keep the recommended higher idle.

But, in a real answer to your question, it has been proven that it is detrimental to idle today's diesels for any longer than needed prior to moving the coach for departure or ? There's lots of stats proving it's bad for their health.
Scott

 

[cbeierl]

On mine you can use the accelerator pedal to set the RPM you want and then the SET button will hold hit.

I just went outside and verified how mine behaves. At idle, pressing and holding the RESUME button will cause the RPM to increase slowly, stopping when the button is released. A single press of the RESUME button may or may not do anything, depending on the last set cruise value. The RESUME button behaves the same way in motion.

If you press the accelerator pedal you can then use the SET button to select that RPM. Holding down the SET button (when the cruise is set at idle) will cause the RPM to decrease slowly. Again, this is the same behavior that the SET button has in motion.

 

[AFChap]

if yours works the way you're saying it does, then pushing the set button will also increase speed in the coach while driving, correct? And normally pushing the Accel/Resume button and holding it is used for increasing speed while driving.

Nope, while driving, "set" sets cruise speed at the current speed, or while cruising tapping "set" decreases speed. And tapping "Res/Accel"increases speed. But when parked hitting "on" and then "set" does increase and set the idle speed to apx 1k. I tried it in a Tiffin diesel one time and it did the same. Don't ask me to explain it, I just know it works just like my manual describes. I have never tried holding either button down to see whet happens ...now I am curious and will do that when I take my coach in for service tomorrow! Mine is a Cummins, but I can't imagine why that would make the Smart Wheel behave differently...

 

[FIRE UP]

Chris,
I have pressed on my "Resume" button a few times in a row and, it will raise the RPM, somewhere around 100 rpm, plus or minus, each time it's pressed. Or, as stated, if you press and hold it, it will continue to raise it as long as you're holding it.

AF,
Well Sir, apparently yours works as normal when cruising. But raising the RPM with the Set button while sitting still and just idling, is certainly different from mine and Chris's above. And yes, if you press the accelerator pedal to a given RPM, then push the "Set" button, it will "hold" that rpm.

To the OP,
I hope all this discussion on this cruise stuff has not indicated a "stealing" of your post, it is all directed at your subject.
Scott

 

[bucks2]

I just push the "Fast Idle" button on the console and it goes to 1100 rpm and stays there. Turning the switch off or tapping the brake pedal returns the idle to it's normal setting. It works great for building air after sitting for a while. While the manual says the cruise control will do it also, one button service is much easier. Your coach manufacturer should be encouraged to make a single button available to you also.

Ken

 

[AFChap]

I looked at the Smart Wheel manual on my computer and after describing each cruise control button function, it also says "Actual function may vary by engine/chassis." ...and the instructions on how to set fast idle are not in that section. I have a Cummins ISC on a Spartan chassis.

 

[FIRE UP]

I just push the "Fast Idle" button on the console and it goes to 1100 rpm and stays there. Turning the switch off or tapping the brake pedal returns the idle to it's normal setting. It works great for building air after sitting for a while. While the manual says the cruise control will do it also, one button service is much easier. Your coach manufacturer should be encouraged to make a single button available to you also.

Ken

Ken,
Roger that Sir. We had "Fast idle" in all of our fire trucks. It was a no-brainer for even the dingiest of firemen. I do wish they'd have done it like that in our coach too. Oh well, we have what we have and it works.
Scott

I looked at the Smart Wheel manual on my computer and after describing each cruise control button function, it also says "Actual function may vary by engine/chassis." ...and the instructions on how to set fast idle are not in that section. I have a Cummins ISC on a Spartan chassis.

AF, Well Sir, there you have it. It very well may be that because you have the Cummins power plant, you have somewhat slightly different button operations on the Smart Wheel. Cool.
Scott

 

[bachler]

Whooo When did you discover That;; It's been that way for years;;