Engine/Transmission (1998.5 - 2002) Can you fast idle a Cummins to warm it up?

[Tomscreek]

I know it's not good to idle a Cummins for too long at regular idle because of the low temp and piston wash but if you start it up and have it idle higher, is this ok to let it run a while and warm up? And if so, about what RPM is good?

 

[ToolManTimTaylor]

Not unless there is a load on the engine with a device such as an exhaust break. A high idler is generaly used to MAINTAIN heat once it has been warmed up via driving.

 

[bfreel]

Toolman, why do you advise a load on the engine as opposed to no load to warm it? If the high idler was used, once the truck is warm, wouldn't that mean the truck is at a standstill, idleing? In other words just to keep some heat in it.

 

[truckstom]

I idle mine all the time to warm it up. Even in warm weather.

Excessive idling is for extended time, as in hours and hours... . lettin' it idle for 10, 20, or even 30 minutes isn't going to hurt it. IMO

Driving it COLD will.....





Disclaimer; This is all my opinion, from my experiance, yada yada

 

[fj40charles]

I think the best and fastest way to warm up your motor would be to start the engine and let it idle for a minute or tow and to drive it. Plugging it will also help the warm ups.



I think you'd get too much cylinder wash down letting it idle for extended times.



My humble 2 cents... .



Charles

 

[ToolManTimTaylor]

IN Tomscreek'S CASE HE IS IN MONTANA ... oops caps lock ... . anyways it is not good to cold idle a diesel period. the rings are cold alowing s thousanths gap between them and the cylinder walls thus wasdown occurs. A load on the other hand actualy forces them outward thus creating more complete combustion. Just look at your EGT guage one day when it idles at a cold start or coasting down a steep grade for that matter. Being there arent any throttle plates on our trucks the injection pump is supplying enough fuel at idle to keep it running and maintain rpm's for oil pressure and battery charging. Whereas a gasser fights against the throttle plates that create a manifold vaccuum which is a sort of load in itself. I was allways taught to start em build oil pressure and Gentlefoot driving it til the guage starts to move.

 

[JR2]

I have be idleing by truck for a while (10-30 minutes) when it is cold out since I got it. I also have had oil analysis done on every sample and they don't show any diesel in the oil. I will say that I think letting it just idle at 750 rpms for long periods of time is bad, but using a high idler like the Practical solutions one I have (or the high idle reflash) pose no problems. Where I work it is not uncommon to leave your truck on high idle for 12 hours at a time..... its better to let em run than turn em off when its -40.



In a perfect world I would have an engine heater (espar or webasto) and use it instead, but I don't so high idle is better than nothing.



like always... its just my opnion and it may not be worth anyting. .

 

[LSMITH]

I agree that you can and should get in, start it, and drive off gently. So little heat is built idling that it is of little value, even at 1200 RPM. My pyro is digital, so I know exactly what the temp is. I see about 250 most mornings when I fire it up lately with the temps in the low 40's and high 30's. The grid heaters put enough load on that combined with the warmer air in the intake EGT goes up to 315 or so under the same conditions, as they cycle temps go up and down. Idle up to 1200 and EGT goes to 320 with the heaters cycling and 275 or so with them not cycling. None of the temps I have seen at idle with no load are enough to warm the engine much at all in a resonable amount of time, I would say reasonable is 10 minutes or less. Pull it into drive and set the emergency brake and we have another story, temps go up to 375, warm up is a lot faster. Exhuast brake users I have talked to have said 500-600 is normal for a cold engine with the brake on. Even in drive with EGT at 375 that is not enough to maintain operating temp on a fully warmed engine, and if it will not maintain operating temp there is no reason to keep it running. Idling also wastes fuel, I would guess that a lot of guys that moan about poor economy idle a lot.



Get in it, light it and drive off unless you have an exhuast brake.

 

[andrewkoperdak]

I would just plug it in and not idle it long.

but.....

I am a dieserl marine engine mechanic. All our engines MTUs and Detroit 149s are not permitted to take a load till they are warmed up. In fact the MTU's computer will not permit any opereation other than idle till they warm.

I know these are marine diesels but the arguements that are being presented make my points valid none-the-less

Finally, when I need to warm my engines faster I load the engine by staying in a lower gear to get the exhaust temps to around 600 degrees. This usually warms it pretty quickly. No I don't lug the engine.

 

[bfreel]

Well, we sure have a lot of opinions on the subject. Here is what I do, now that we are into cold weather here in New England. I use the block heater during the night, unless the truck won't be used early the next day. When using it early, I start the truck, turn the high idler to 1200 RPM and let it run for 10 to 15 minutes. Before driving, I turn the idler off and do my normal thing for the day. A point to make here is, I have an electronic high idler, if it isn't shut off completly, the fuel system doesn't go back to it's program and I feel a loss of power. If the control knob is turned all the way to low, but not clicked off, there is a definite loss of power. Keeping a steady foot on the throttle, and clicking the knob to the off position, you will feel a surge and your speed picks up.

I for one, feel that warming an engine, and also trans and rear end, before putting a load on them. It settles everything into working mode. MHO

 

[Snow man]

I'm with TTMT,let it idle cold only long enough to get oil pressure,unless its below 0 and the engine is running rough. drive it like theres an egg under your foot until the temp comes above 140,then you can run up to about 10 psi of boost,once its hits full operating temp full power ahead.

 

[ToolManTimTaylor]

There's the rule 10&10 no more than 10 lbs under 10 mins of driving! Thank you Snow that's what i was looking for instead of

Tim said before: "Gentlefoot"

 

[dpetre]

Winter Idling

I have yet to see where letting a diesel powered vehicle warm up for ten, fifteen or 20 minutes hurts any thing. You will cause more damage to the engine, and drive train by running it cold. Sure plug the vehicle in helps it start better but letting it warm up will make it last longer. When it is 50 below and the vehicle is parked out side it has to warm up before you can drive it. Ten minutes at idle just does not cut it. My fords all had fast idle warm controll mounted in them because with out them they just would not warm up. I live 34 miles West of Fairbanks Alaska where winter is a way of life and 50 below zero is just a thing.

 

[ToolManTimTaylor]

http://www.dieseltruckresource.com/yabbse/index.php?board=4;action=display;threadid=6208





https://www.turbodieselregister.com/faq.htm #'s 11=12

 

[CUMINNTSTRKN]

i also live in helena mt, and i use a high idler almost everyday. this morning it was around 10 outside. i fired her up are turned the rpm up to 1400rpm. i went out around 10minutes later and the windsheild was clear and i had heat.



my high idle reflash will also work but when it turns off the 3 cylinders it smokes really bad so i use my high idler more. the reflash warms it up in a hurry, 700egts at 1200rpm vs 400egt at 1400rpm with the high idler.



jim

 

[Tomscreek]

Thanks for all the info. When I'm at home I really have no problem, I park in my attached garage and it rarely even gets below freezing. However I have a cabin in the mountains and no garage there yet. Can I just stick something between the brake and gas pedal to get the rpm's up to 1200? I also put a oil pan heater on and have a generator where I can plug both the block heater and the oil heater in for an hour or so.

 

[CUMINNTSTRKN]

you can get a electronic one at http://www.psdieselproducts.com/



jim

 

[Bratton]

I'll second some of what Cummins Strkin said, I had the cold weather Idle feature turned on right after I bought the truck. My dealer here in Bozeman,MT had never heard of it before I told them about it, but they did it and it works. When it's below freezing, the truck increases the idle speed to 1200RPMs and when it's near zero, like it was this morning, it stops fueling 3 of the cylinders so the engine has to work harder. After 10 minutes of idling this morning, I actually had some heat. I wish the 3 cylinder idle would kick in at about 20 instead of 0 but this is adequate.

 

[bfreel]

The electronic is the one I have, and like it.

 

[tcourse]

Don't forget

In cold climates use a winter front, cardboard, or what ever and

block some of the airflow thru the radiator.

Also the AC compressor will add load to bring EGTs up.



TC