3-CYL mode story + at what temp??

[nickleinonen]

my truck ramps up to high idle after about 2 minutes when the coolent temp is lower than operating temprature and when it is cold outside. my truck will also start up right into high idle when it is cold enough. i wonder if it will ramp up to the high idle right away on start up if you have your foot on the brake? [pressing the brake disables the high idle when it is there, but will it stop it from happenning?]

 

[XcumminsX]

i had nothing but a straight stream of white smoke coming out of mine when it was really cold i didnt know that meant the fuel was gelling..... Where can i get these additives for the number 2 diesel fuel.....

 

[Mopar_Mudder]

Originally posted by XcumminsX

i had nothing but a straight stream of white smoke coming out of mine when it was really cold i didnt know that meant the fuel was gelling..... Where can i get these additives for the number 2 diesel fuel.....

No that doesn't mean the fuel is gelling, you are thinking too hard. When is it real cold you are going to get white smoke just because of the fact the you are introducing warm exhaust to cold air, also the cold engine generally wont burn all the fuel untill it get warm. As things warm and it will go away.



The fuel gelling I was refering to has to do with the rough idle condition.

 

[RobbieH]

the manual says when starting in very cold weather to run the throttle up to 1,000 RPM to set the high idle. Since some of you mentioned you just started it, maybe that's your issue?

 

[lschultz]

No 3cyl mode

Last time I talked to my service man he said the 03-04 trucks do not have a 3 cyl. mode only a high idle feature. If yours is running on 3cy Tommy you have some other puter glitch. You better take it to the back and get them fellows to check it out.

 

[DF5152]

does your truck idle smooth when its in this mode this morning i started mine it went right to high idle and was idling rough and dumping some smoke every once in a while

 

[KBennett]

The coldest I have started my truck is 9*. It took right off in the high idle mode. Lately it has been around 20* in the morning and it takes about 30-60 seconds for the high idle to come on. I have never seen or heard anything that would make me think it is in 3-cylinder mode and I always run the idle up to 1000 RPM for about 5 seconds.



My truck is bone stock.

 

[Tomeygun]

Originally posted by DF5152

does your truck idle smooth when its in this mode this morning i started mine it went right to high idle and was idling rough and dumping some smoke every once in a while

no, not smooth at all untiol you touch the brake pedal...



i am still researching the 3-cyl mode through the tech line

 

[n9oig]

Mine goes straight to high idle as soon as I release the key the brake nor speed slow it down which is contrary to the high idle specs.



Kevin

 

[rbattelle]

Originally posted by n9oig

Mine goes straight to high idle as soon as I release the key the brake nor speed slow it down which is contrary to the high idle specs.



Kevin

If it's cold enough, it will go to high idle immediately after startup. That part is normal. But pressing the brake or getting speed above ~3 mph should cancel it.

 

[jakprince]

So does your "trash truck"warm up any faster than everybody else's or is this noise for nothing

 

[rbattelle]

Originally posted by rbattelle

If it's cold enough, it will go to high idle immediately after startup. That part is normal. But pressing the brake or getting speed above ~3 mph should cancel it.

I'm wrong... sorry! When it does the immediate high-idle it won't cancel despite nonzero vehicle speed or service brake action.

 

[Tomeygun]

Originally posted by jakprince

So does your "trash truck"warm up any faster than everybody else's or is this noise for nothing

i guess the "no nothing" is the correct answer

 

[Blakers]

Originally posted by rbattelle

I'm wrong... sorry! When it does the immediate high-idle it won't cancel despite nonzero vehicle speed or service brake action.

Mine drops down to 750 if I push in on the brake. Seems I have to push on it and not just tap it.

 

[RedSmoke]

Getting in on this thread late, but here's what I've found...



Started it the other day at -16°F and it went straight to the high idle. It won't actually warm to operating temperature this way (gets my egt's to about 250-300 and coolant to 160°). I never drive away with it in the high idle mode, so I just tap the brake or blip the throttle real quick. Either of these methods work fine.

 

[Blakers]

Originally posted by Blakers

Mine drops down to 750 if I push in on the brake.

Well I have to correct myself. It wouldn't do it today. The idle stayed up at 1000 rpm until I drove down the road a ways.

 

[smartineau]

My high idle has a life of its own, in the low 20's sometimes it goes to high idle right away and sometimes it can idle for 2 minutes before it will turn on.



One day I pulled over to read a map (it was at operating temp and had been for over 2 hours) put it in neutral in about 30 seconds the high idle turned on, it was about 20 degrees out.



steve



Is ther a way to manually turn on the high idle other than using a brick or wedging an ice scaper between the pedal and the seat?

 

[rbattelle]

Originally posted by smartineau



Is ther a way to manually turn on the high idle other than using a brick or wedging an ice scaper between the pedal and the seat?

If you find one let me know. Actually, since high idle is a function of IAT only (apparently), you might be able to make a simple circuit wired into the IAT sensor circuit that would fool the computer into thinking it's -10, which would cause high-idle to engage after 2 minutes or so.

 

[JGoodwin]

the 2gen trucks have a 3 cylinder idle. the 3gens do not have 3 cylinder idle. just ramping up idle and ajusts the timing to try to keep heat in the head

 

[JGoodwin]

if you want to fool the computer into high idle. the intake temp sensor next to the air filter is the sensor to be played with. They have two intake temps. one in the intake itself which is a temp and pressure sensor and the one in the inlet. thats why if the truck is a operating temp and is at idle it will read the cold air coming in and ramp up the idle even though its already at operating temp