We have touched on the sbuject some in a few of my other threads and it has lead to a lot of guesing and confusion. I'm thinking, after yesterday, I may have figured it out, or maybe a new theory on it. This is in relation to $0D/$0E and the 7427's, for the new comers. For the past discussions you can read through my old thread here: http://www.gearhead-efi.com/Fuel-Inj...st-impressions
We have probably touched on it some in other threads too.
It all started with the never ending quest for the perfect tune, just how you want it. There are a few quirks and annoyances with the BMHK bin I have been using since the start. Its a 0E 7.4L manual trans bin. I am running a manual trans in my jeep. Back sevral months ago I tried a couple random bins just to see how they ran. After a few with failed results I had one that worked ok. It was BJYM, a 0D 5.7 auto bin. I did all the normal work to it, disabled auto trans, set man trans, disabled trans error codes, turned off egr, inported my injector and cylinder sizes, and my fuel and timing tables. Also did all the needed MPFI mods to it, as well as a handfull of other parameters (like dfco and pe). I worked on it for a while, and remember it running pretty good, funny though, I had to retune my fuel maps a bit. It ran pretty good other than it having a hard time starting. I remember copying a few of the crank to run rpm parameters from bmhk but it didnt change. I later gave up on it and went back to bmhk. Fast forward to this past weekend. Still being annoyed by the few quirks and other nit picky stuff about bmhk, I decided to try that 0D bin again, but decided to do a little more work to it.
I burnt it back to a chip and tried it again after resetting the pcm. Cold start there was not really any problem, and cold performance and manners were way better, none of the rich and poor running problems of bmhk (I have a thread with a video of it somewhere on here) Warm start I had to crank a good bit longer, and it would kinda spittle to life. Just not like it should. It did however, have a much smoother idle than bmhk. Humm, odd. Idle speed set the same, all injector flow and other setting I could think of were also the same, but for some reason it was just smoother.
Well I decided to work on the starting issue first. So I spent probably 1-2 hours with two instances of tuner pro, both bins and the parameter finder, and copied all parameters that had to do with "crank to run" or "start" TA DA, I now have the fast starting at all times just like bmhk did. I am now starting to like this bin. Odd, I have zero idle problems like you would think you would with a auto bin. Has never stalled once or even come close. One thing it does do, is the jolt when exiting dfco. The whole vehicle jolts just like a super light/fast blip of the throttle. I had that problem with bmhk, and it turned out being the post dfco AE pulse. I changed it to zero and it went away. I changed it to zero in this bin but still had the jolt.
One thing I noticed about this bin that got me thinking, was it just didnt seem to pull out as good. Kinda hard to discribe, but bmhk would pull out and go, this one it didnt do it as well. Like I said, kinda hard to discribe. I then remember back to our discussions of this "throttle kicker" and its list of parameters thats in these bins. I remember in bmhk, if I turned off the flag for throttle kicker enable, it wouldnt pull out as good. So that percked my curiosity. I pull both bins back up and start looking at them. BJYM naturally did not have the flag checked, and all the throttle kicker parameters did not looks useable. So I decided to run a test. I copied all throttle kicker values from bmhk into my working bjym, I then turn on the flag and give it a try. Wow, it will now pull out and go like bmhk did, and now, suddenly, the post dfco jolt is gone, now its just ever so gentle and smooth. Ok, now I am REALLY curious. What does this setting do?
I load the bin to the autoprom, emulate it, start datalogging and go to the 1/4 mile long abandoned dead end road close to the house. I turn the TK off and watch iac counts and injector bpw while pulling out, and when in and exiting dfco. I then turn it back on and watch again. Here are my findings:
With my running bjym with the throttle kicker disabled, iac opens slightly when pulling out, goes up to around 80 or so counts. Stays around there in dfco and when exiting it.
With throttle kicker enabled (and the parameters for it from bmhk) as I start pulling out, iac opens very quickly and pegs to 150 counts real fast, basicly giving a boost of air to help when pulling out. When in dfco and when exiting, it stays at 150 counts, then start closing after fuel has been turned back on.
SO, it appears (my theory anyways) the "throttle kicker" parameters are most than likely a manual tans iac logic. I have not had time to check other 7427 man trans bins (4.3 or 7.4) to see if its active in them. Though, it may not be active in all of them, as I have time I will do some more looking.
So there my be "throttle kickers" on some vehicles, but why would they put parameters for them in bins/code for vehicles that would not have them, and why do the listed parameters seem to make no sense in relation to what you think there should be for controlling one. Also, wouldnt the wiring diagrams also have the wires for the throttle kicker in them, such as signal in and out. So I am thinking maybe "throttle kicker" may not be the most correct name for this feature in these pcm's. Or maybe it is the correct name, but its used in a different context.
Thoughts, ideas, other theorys?
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Originally Posted by JeepsAndGuns
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