Is high idle a feature on early 03 04 trucks?

[Darkbloodmon]

NC had its coldest morning temp yet earlier last week if iirc for the piedmont region at 27* aprox. Given the engine work I've done this year I decided to take some observations given the temperature to feel out a baseline of what to expect heading into "cold" weather for the south eastern states.

Batteries are from 2017 Mopar branded lead acid group 65s . Always topped off with dirt free tops/clean terminals, uncoated.
New battery cables/cross cable this year from Geno's supplier
New TYC alternator stock output.

Cold start: Block heater not plugged in over night, Grid heater intact and functioning, Power service in tank and fresh fuel filters on a non heated Titanium Fass 95 prior to a new S&S 6.7 CP3 install in April. Georgia fuel from Duluth QT:00731 11/17/21; 1st and last fuel stop before my return back to NC from Fort Worth Texas.

First crank, nominal turn over within 4 sec spec. No white smoke until after a few moments of idling. White smoke persisted until EGT temp read around 250*+. Battery voltage slowly came up with grid heater draw.

Truck is idling fine without hesitation. I notice as im observing the exhaust pipe (outside the truck) for smoke that the engine speed starts climbing without throttle input and settles at 1100 rpms apprx. I observe for a few moments to see if will continue to climb before popping the hood and giving throttle input at the APP housing throttle linkage lever. I hit around 2500 (by ear) a few times and let it settle. Rpms return back down to 750 and it idles without issue. A few moments go by before engine speed climbs again to settle at 1100rpm. Battery voltage was nominal just past 14v during the times the engine idle up to 1100 without throttle input.

Is this a high idle feature built into the ambient air temp sensor, and grid heater system? Or is it just the grid heater pulling amps and the ECU responding by spinning the alternator faster?

 

[AH64ID]

That’s normal. Below ~32° and above ~15° the engine will go to fast idle (high idle is rated rpm no load) at 1000 rpms. Below ~15° it will go to 1000 as soon as you start it.

27° is nothing. Block heater and grid heater aren’t needed for good starts on healthy engines. The block heater does help generate heat faster if you have a short commute or want it.

Was it smoke or water vapor?

On my 05 I found that the block heater was about 90% effective with 90 minutes of operation, meaning it would only get a few degrees warmer with overnight use. The 05 was so cold blooded (cam, turbo, coolant filter, tuning) that when I drove it regularly I would use the block heater on a timer just to get some heat sooner in my drive, along with a winter front. Without the block heater it could take 12-15 miles for the thermostat to open on a COLD day.

The 18 heats up MUCH faster so I don't bother with the block heater.

 

[Ozymandias]

I had mine go into 3-cylinder mode on a really cold days and extended idling, that sounds funny.
Don't be scared if yours does that too.

 

[BarryG]

Agree with AH64ID. Just want to add one more tidbit as I think it applies to your year though it may have just been a later 2nd gen thing. If the fast idle threw you for a loop wait until it is cold enough and the 3 cylinder idle kicks in when it gets real cold. IIRC the regular fast idles kicks in after "X" seconds of starting if cold enough then the 3 cylinder will kick in if it is cold enough another "X" seconds later. I know on my 01 the first few times that kicked in I was like what the heck is going on thought she was gonna blow for a minute. I didn't usually let it idle long when cold if the windows and mirrors were clear I started it and usually took off in under a minute. However my ride out of the neighborhood is 20mph, a couple stops signs and down hill to the main road before I get over 25mph. If I had to clear snow, ice or frost the truck is idling while I do that and when finished get in and go as above whether normal, fast or 3 cylinder idle going at the moment.
Pretty sure the 3 cylinder idle went away at some point just unsure when. I know my 17 never did it and it had seen temps low enough, the 22 hasn't seen cold enough temps for it to happen but the regular fast idle did kick on the other morning. Forgot my phone in the house ran in to get it and came out and she was at fast idle it was in the teens that morning.

 

[AH64ID]

I had mine go into 3-cylinder mode on a really cold days and extended idling, that sounds funny.
Don't be scared if yours does that too.

On your 04.5?

Everything I have seen in the ECM programming and read about said that was a 24V (98-02) only thing.

I've been well below zero and never had it happen to my 05, even on a cold soaked -24°F start.

 

[elephantrider]

2nd gens had the 3cyl...

 

[Darkbloodmon]

Was it smoke or water vapor?

Smoke, What would water vapor indicate? I previously thought that water vapor was a byproduct of gasoline engines in exhaust gas before looking up an academic paper prior to writing this response.

 

[AH64ID]

Smoke, What would water vapor indicate? I previously thought that water vapor was a byproduct of gasoline engines in exhaust gas before looking up an academic paper prior to writing this response.

Water vapor is just condensation in the exhaust heating up and being pushed out. It does happen on diesels, thou not as much as gas engines... that is on diesels without DPF's and SCR's as those look like a gas rig on a cold day.

What's the age of your injectors?

 

[Ozymandias]

On your 04.5?

Everything I have seen in the ECM programming and read about said that was a 24V (98-02) only thing.

I've been well below zero and never had it happen to my 05, even on a cold soaked -24°F start.

I think so, it sounded, lets say, weird.
Maybe it came with the last available ECM Update that my Shop did in 2012.

But I've not heard it for years now, probably SMARTY erased it after 2015 when I bought that.

 

[Darkbloodmon]

Water vapor is just condensation in the exhaust heating up and being pushed out. It does happen on diesels, thou not as much as gas engines... that is on diesels without DPF's and SCR's as those look like a gas rig on a cold day.

What's the age of your injectors?

Makes more sense then given the higher EGT temp evaporating the vapor before it makes it out the system.

I have the exact date and miles in my log but a year and a half to two years max. Stage .1 BBIs.

 

[Blakers]

I had mine go into 3-cylinder mode on a really cold days and extended idling, that sounds funny.
Don't be scared if yours does that too.

Mine does that when it's really cold. Did it since new. Sounds weird to have it missing all over the place, but I guess it's there way of warming up the cylinders faster.

 

[SSage]

My early 03 rarely goes to high idle on start up even below freezing, so when its really cold we use a throttle stick thingy that pushes off the seat frame. If it does fast idle it doesn't stay there long, so I have to use the stick. Mine is one of the first 305 HO trucks built. Plugging in the block heater when with temps in the teens makes a huge difference, if I remember to do it!

 

[Blakers]

My early 03 rarely goes to high idle on start up even below freezing, so when its really cold we use a throttle stick thingy that pushes off the seat frame. If it does fast idle it doesn't stay there long, so I have to use the stick. Mine is one of the first 305 HO trucks built. Plugging in the block heater when with temps in the teens makes a huge difference, if I remember to do it!

I bought mine in May of 03. Not sure where that puts it in production, and what changes were made that year.

 

[CrewCabDiesel]

What about manual high idle mode?
Start the truck, turn cruise on, press set speed, idle will go up to 1100 rmps until you turn it off or depress the brake petal. You can activate it reguardless of outside temp.
Been using it for years, I have a early 2004

 

[Udaloy]

Stock high idle feature was only available on automatic transmission equipped trucks.

 

[Killer223]

Stock high idle feature was only available on automatic transmission equipped trucks.

there is a pin on the ecu you can ground to give the manual trucks high idle with the cruise control feature.

 

[Udaloy]

Wah? Never heard that before. Which pin? Does that mean you put a switch inline with that wire and ground it when you want that feature? Or do you just permanently ground that wire?

 

[seafish]

^^^ I have a "how to" on this in my files --
SORRY I do NOT have the atttribution for the info below, though very likely was a TDR article or a TDR member .


NOTE : these instructions have several alternatives in Steps 1 through 4, so please read and follow carefully and proceed and your own risk !!!



So not to confuse the Dealer when he tries to enable the High Idle in the ECM, it's best if you've electro-mechanically "enabled" it first with either Step-1 or Steps-2 thru 3;


1) Buy the $200 clutch-switch kit and install as instructed. - Pass Go - straight to Step 4…


2) Install a "dummy" clutch-switch by shorting the ECM connector-B Pin #22 to ground as follows: (Note this probably circumvents someone’s concept of safe power-train operation as depressing the clutch with this method will not disengage the high-idle "cruise" setting)


2a) Buy a new ECM connector pin (I bought the Cummins Pigtail part number #3164263 for ~$10.00+tax at a local Kenworth dealer) or use an old junk yard harness to salvage a single pin with a ~6"-7" lead.


2b) If you bought the pigtail #3164263, the lead will be too short, so pick up some 18AWG to extend the lead length. The pigtail already comes with a crimp connector and a heat shrink insulator ready for the extension-lead.


- Crimp the ~5" 18AWG extension-lead into the pigtail and hit the heat-shrink sleeve with a heat-gun (or a lighter!!) Please check your own extension-lead lengths before crimping - this ~5" is from my lousy memory !!


- Add a 1/4" ring terminal to the end of the extension lead (this'll connect to a ground post) - I bought the ones with a semi-clear blue "plastic" sleeve, the sleeve is actually a weather-proof heat shrink. Hit the heat-shrink sleeve with some heat.


3) Remove plug B on the ECM (the 50 pin connector on the drivers side of the engine closest to the rear of engine with a 4mm Allen screw in the center). Note: this is probably best done with the both batteries disconnected first (I did mine with the batteries connected - sloppy).


3a) Push (use a paper clip) the sealing plug out of position #22 (starting at to left, count across, there are 50 pins total, #22 is second in from left, third row down) Note: #22 is the PTO/Clutch switch sense terminal (page 8W 80-98 in the shop manual).


3b) Insert the pigtail-lead into the back of the #22 until you feel a positive detent (click), lightly tug the wire to ensure that it's been properly inserted and cannot be removed. Note: Make sure that you've properly identified #22 - if you've put it into the wrong position, you'll probably need to head over to the dealer to use a special pin removal tool...


3c) Reconnect the ECM connector, don't bother trying to push it on, just seat it square on the ECM connector, and carefully thread the 4mm Allen screw until it bottoms out.

And there ya go!!

 

[petersonj]

Water vapor is just condensation in the exhaust heating up and being pushed out.

Just nit pickin' here, but water vapor is not visible to the human eye because it is in a gaseous state. It is condensation that is visible. So, it is condensation that is seen coming from the tail pipe when the conditions are right.

To put things into perspective, everyone has seen contrails (condensation trails) left behind from a passing jet plane overhead. A little closer observation will show that the beginning of the visible condensation trail forms at some distance behind the exhaust of the engines. What you can't see is what is in between the engine exhaust and the beginning of the condensation trail. That is water vapor and it is invisible. So as the jet passes by, the water being observed in the condensation trail had already passed from the engine in a vapor state and could not be seen until the condensing process began.

Any combustion process produces water. But, because the combustion process produces considerable heat, the water will be found in a vapor state at the source of the combustion. All internal combustion engines produce water. The water leaves the engine in a vapor state. Depending upon many ambient conditions, the water vapor can make it all the way out of the tailpipe and mix with the surrounding air, and never condense. Or, completely the opposite can happen - conditions could allow the water vapor to begin condensing in the exhaust system before it even leaves the tailpipe. The operation of catalysts and particulate filters on all kinds of exhaust systems also influence the amount of condensation that may be seen (or not seen) coming from the exhaust system. Engines with throttle plates (mostly gasoline engines, but some diesels) are more prone to have condensation leaving the tailpipe.

I only bring this to light because many times I have known some people to be overly concerned when they have seen a large amount of condensation coming from the tailpipe of their vehicle. Most of the time it is just normal.

- John