Blue,

glad it works for you. So, if I understand correctly, you dropped the bats for 45 min without doing an APPS reset.?? That's good info for others looking to get this feature working. Must be something with the reflash and a need to reset with the EZ. Was your EZ removed during the reset/activation or in line?? I pulled mine out and then reflashed.

jrs,

3 cyl drop sounds kinda sick actually. The ECM maintains ~1200 rpm but with the 3 dropped it's sort of "puffity" (like a gasser with a few plugs out) at the tail and she rattles a little louder. She has to work a little harder, pyro gets up to 700 or so instead of 300 and it definately works.

Still catches me by surprise when I'm not paying attention and getting the snow off 'cause it just kicks in suddenly.

Others have posted this feature is disabled with use of a block heater, even for a few hours. My experiance suggests not so. As long as the parameters are there, the ECM kicks the idle and 3 cyl drop in. Even when you think she's had enough and tap a pedal. She'll settle down to a regular idle for about a minute and ramp up again. Even goes into 3 cyl drop, again, if the conditions are still present.

Put her in gear and go, that's a different story.


*****, the earlier post by Mechanos would suggest you need a reflash and activation. As far as 'sure fire" goes, get a dealer scanner on it. Or, let her sit out (15F) or colder overnight without a block heater.

I'm sure it gets that cold in PA

 

what I have found is it still works when plugged in but it has to be a lot colder before it kicks in .the heat from the engine probably warms up the intake air a bit

 

Taz

I did the full APPS reset. I didn't want to spend the time out in the cold disconnecting and reconnecting the batteries twice just to save the few seconds more it takes to resets the APPS.

I was a little disappointed though becuase it didn't go into 3cyl mode this morning. It got down to about 0 degrees for most of the night and was 8 degrees when I went out. I'm figuring that it wasn't cold enough to kick in since the grid heaters warm the air up enough to get it over the 15 degrees needed for the 3cyl to kick in.

Mike

 

Blue,

I think you're right on the edge temperature wise. I find it's a little finiky and not a real exact temperature thing.

I've had the 3 cyl drop happen at 18F and not at 12F.

It'll happen with those temps for sure

 

I am guessing that this sounds similar to trying to get a truck to start with air in the injector lines, They don't sound happy trying to run on a couple cylinders.

 

Well if fast idle works, then 3 cylinder will work if it is cold enough. I agree that it varies around a bit on temp required. SNOKING

 

I tried to have mine enable 3 times, yes 3.

Each time I picked a nice cold night and "forgot" to plug it in.
Fired it up the next morning and nothing, no high idle, no 3 cyl shutdown.

Had to be as simple as the tech forgetting to click "yes" on the enable or not screen.

3rd time's the charm.

I took a copy of the TSB and demanded they find a tech that had done it before.
They said since I was out of the 3yr/36,000 warranty that they'd have to charge me $98 bucks, I said bull pucky, according to the TSB it is to be charged at .5 hours, and is reimbursable under the warranty.
They dropped the charge to $45 and said it wasn't covered under the engine warranty since they were working with the computer, I said whatever, if it doesn't work I'll expect a full refund.

That night it seemed to be cold enough, so I didn't plug in.

Started it the next morning and in about a minute the idle climbed up to 1200rpm (note, RPM, not RPM's )

Hasn't been cold enough for the 3 cyl though, but as soon as it is, I'll try to remember to forget to plug in.


phox

 

ok, I left it unpluged (7 degrees F yesterday morning)....

fire her up, it idles for a few second, then the RPM's jump higher and it got alot louder....runs like this for about 45 seconds, then the idle drops a little and it gets a little quieter, there is a clicking sound (sounds like a relay kicking on) then the idle jumps back up and stays there longer, then repeats...

so do I have it or not....

 

That sounds like the grid heaters cycling. It should idle at 1200 RPM if it has been enabled. After the reflash, they have to go into it and turn on the three cylinder option for it to work at all. SNOKING

 

*****,

Don't think so.

There's no mistake when she drops 3. Heads turn and a lot of "what the....."

I'm with Snoking, that's just the grid cycle and the a/c compressor (clicking)

 

Ok, thanks guys....I'll have to look into getting that done...

 

Well, I was a bit disappointed this morning. My truck was unplugged last night and it got down to about 5°F. It was about 6°F when I went out to start it up and tryed to do so with one cycle of the grids..... start but immediately died. Cycled grids again and it fired up.... and then ramped on up to high idle. Even though it was plenty below the parameter for the 3-cyl mode, it never kicked in. I don't know if it makes any difference, but the TSB says one of the parameters is 1200 RPM, but my truck never makes it there under high idle. It only idles up to about 1150 RPM per the tach but never gets any higher. Maybe that is why it won't go into 3-cyl mode. I don't know if it will make any difference or not, but I figured this evening, I will reset the APPS and try it again tomorrow morning (it's supposed to get down to -2°F tonight).

 

At -2 is will most likely go to 3 cylinder. Hang on to your private parts when it does. SNOKING

 

What does "reset the APPS" mean?

What does it do and how do you do it?

Thanks...

 

Mech,

I've found the "rest time' a major influence.

The truck has to cold soak for about 10 hrs and shed internal heat in order to make the temperature parameters.

If the truck sits for less than 10 hrs or so it may not drop three.

Overnight will normally do it, although we had those temps last night as well and I didn't even get a high idle this morning. (was out until 22:00 and on the road again at 06:00)

My guess is even at 5 F you need a longer soak time. If it sat all weekend like that I would be surprised if it did not kick in.

m2cw