Cruise control never tells engine to use 100% throttle position

[c5dura]

After climbing the same hill many times over the last 6 months, I'm pretty confident that when running on the cruise control, it will never send a throttle signal to the engine of more than like 95-97% or so.

Scenario: I'm driving along on the Interstate @ 74 mph on cruise control and start climbing the Blue Ridge Mountains.

The truck will start to slow down, 73, 72, 71, and then drop into 4th and get back up to 74 and hold until I crest the hill.

On the other hand, if I 'help' the cruise control out by manually stepping on the gas pedal when the speed drops to 73 or 72, it climbs back up to 74 without ever dropping into 4th. I must have repeated this 50 times and it works every time.

My conclusion is that the cruise control will not send a WOT signal to the engine unlike the gas pedal. Not a big deal, but I wish they didn't have this safety net built into this drive by wire system.

[mtomac]

Whenever I tow thru big hills/mountains I always "help" the cruise by spooling up the turbo at the bottom of the hill. This definately helps keep the truck in 5th gear.

[Kennedy]

You'd have to watch fuel rate to see just what it is saying as APP values are "0" in cruise control. This is something the APP referencing box mfr's did not figure on...

[sdaver]

a good dose of vitamen c(the juice) will remedy that situation........then you wont need 100% :D dave

[c5dura]

Interesting point John. I might try to log some values w/ Autotap to see what changes when I step on the gas to 'help' the cruise control out going up hills.

I hear you Dave. I just keep sitting on the fence trying to figure out what power adder to go with.

Since I don't have any gauges yet, I feel like waiting for the hot juice w/ controller. On the other hand, I really like the concept of programming the PCM w/ the Predator, especially given the bonus of adjusting for tire size and redline/top speed. But, alas, the power levels are not quite up to par with the Juice, let alone the Hot Juice from what I've heard here.

I'm pretty sure that whatever power mod I go with, I'll wonder how I ever got along without and then I'll get used to the extra power and then if I run the truck without a power adder, it will feel like a dog. At least that was my expericence when I took my vette from 310 to 418 rwhp.

Its amazing how quickly you adjust to increased power levels and then start craving even more. Like they say, there is no such thing as too much horse power (except perhaps when it rains in a light car like the vette with over 400 rwhp) :D

C5dura

[ 05-06-2003: Message edited by: c5dura ]</p>

[Colorado Kid]

With my 6 speed taking the Allison out of the equation I feel like the cruise eventually gets to 100%, it just takes FFFFFFFOOOOOOOORRRRRREEEEEEEVVVVVEEEEEEERRRRRR to do it. It rolls on and off the power so slowly its pathetic. When I point it up a big hill with a big load, where the grades change relatively slowly...like I-70 west from Denver, it does fine...speed drops maybe 2 mph then picks back up. But get on rolling terrain like US 34 east of Greeley and it swings through a 20 MPH span...NO KIDDING!...It goes coasting up the hill until the speed is 5 under the set point before it calls for power, and rocketing past the crest will full, or nearly full power on even though the speed is way over the set point...and I can keep it within 1 MPH by pedaling for myself with the same load on the same road in the same gear. :(