Thread: Question for the Mad Dr.
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Old Thu, March 5th, 2009, 12:40 PM
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Jackpine Jackpine is offline
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Quote:
Originally Posted by orygunf150 View Post
1st and 2nd gear positions cause the PCM to remap the throttle
essentially the throttle gets cut in 1/2 by placing the shift lever into 1st or 2nd. the throttle then is more "sensitive" and you have better control of the wheels.
this is achieved because you now have full pedal travel to control only 50% of your normal throttle...so you don't inadvertently spin the tires by giving it too much gas
it's a little known feature to help you control low speed situations. like boat ramps, towing heavy loads, 4x4 offroad

This is a response from Tylus on the FTE forum regarding the same issue, if it is the pcm remapping the throttle I would think it could be programmed to not do it. Or, perhaps there is a microswitch somewhere that can be bypassed. What do you think Bill?
Shouldn't this be "less sensitive"? (But I'm not trying to split hairs here, just trying to understand this). Effectively then, placing the shifter in 2nd (or even 1st) DOES make the truck less likely to spin tires on startup in a slippery situation.

But now, I've got another problem. From Tylus' explanation, it would seem that you are very limited in total power output if you have locked the transmission in 2nd. As I said in a previous post, that doesn't seem to be my experience, at least not when I'm towing my trailer up a 7% grade in the Colorado Rockies and passing every other RV and semi in sight (since I can maintain 65 mph and they can't). I lock it in 2nd to keep it from shifting back and forth between 2nd and 3rd in this situation which it will do on grades like this. This technique even seems to work on very "twisty" steep roads where the maximum speed is about 25 mph. I have no problem whatsoever getting everything moving from dead slow (around a severe switchback) while in 2nd gear. On shallower grades, of course, I can just lock the overdrive out to keep from cycling between 3rd and 4th.

I guess what I'm trying to ask in all this is: If my total throttle input is cut in half, where the heck am I getting all this power from? Is it Bill's fabulous tune?

- Jack