Torque Q lockup

[eger]

Anybody had experience with adjusting threshold for disengaging torque converter lock-up so pulling hills might only disengage into 4th instead of dropping into 3rd? Base Vibe w/automatic wont even pull interstate hills, and dropping into 3rd at 75 MPH really makes it rev. Not a good thing.

[djb383]

Are you referring to downshifting/unlocking when the cruise control is on?

[eger]

Affirmative. I think there is enough torque to pull most hills in 4th, but it always kicks out and drops into 3rd.

[djb383]

I think some dufuss engineer (hope your not one) did the program mapping in the ECM on a Friday afternoon on his way to the golf course and just said that's good enough. I find if I disengage the cruise control at the base of a hill and use the foot feed going up the hill, I can maintain my speed within 1-2 mph and the tranny won't unlock or downshift but that kinda defeats the purpose of cruise control. Like I said, (removed) poor engineering/programing.

[eger]

Yeah, I are one. But that just means that I agree with you. Didn't figure there was any adjustment available, but had to ask. Will be going in for warranty work soon and will ask the "experts". Thanks...

[djb383]

Check this out, I'm running a ScanGauge which one of the functions is real-time MPG display. If I leave the cruise set and the tranny down shifts, the MPG display drops from say 30 mpg to 10-12 mpg but if shut the cruise off and maintain speed with the foot feed (no downshift), MPG only drops to 20-22 mpg 'till I reach the top of the hill. It would think just a slight change change in programing parameters would make a big difference, IMO.

[eger]

MPG is surely another element of this equation. But when I drive our 100 turnpike/interstate the last thing I want to do is manuever the foot feed...cruise control was made just for me (good chance to get a nap). Really like most things about the Vibe and the wife LOVES it, so guess we trade. Old Civic has almost same size engine, but it DOES pull the hills.

[engineertwin2]

Rather than being some "doofus" engineer...did you stop to think that perhaps the torque might be dropping too low? High revs isn't such a bad thing, it ensures that you keep enough torque to keep climbing - the problem with hills is they tend to get steeper before they shallow out. If your torque drops too low, the engine stalls. Perhaps it was in an effort to prevent the engine from stalling out. That would be a much worse situation.Sure, maybe it will make it on the hills you drive, but they didn't build the car just for you. They have to think of what the car will go through and ensure it's operations and safety of it's passengers. High revs are a small price to pay from an engineering standpoint to ensure the engine doesn't stall...Just trying to think about what type of logic was applied in order to set the shift point like that.

[djb383]

Nah, it was a dufuss engineer that just didn't play with it long enough during development. If you can maintain speed going up hill with only light foot feed pressure, and it doesn't downshift, it still has plenty of torque and is not going to stall. How do you stall an engine with an automatic tranny anyhow? Sure, if the hill is steep enough and the ECM is seeing a high MAP number, it will down shift regardless of the cruise being engaged or not. I'm just saying that when the cruise is on, it downshifts earlier than necessary on a gradual incline. Why couldn't the parameter be set where the torque converter unlocks, allowing an increase 400-500 rpm, holding there for 2-3 seconds, then if the MAP number is still too high, then allow the tranny to shift to 3rd. As it is, if you have the cruise set at 70 mph the engine is turning 2800 rpm. When it downshifts to 3rd, rpm jumps to 4200. And your right, that's not a bad thing, it's just not necessary. A number of Vibers have complained about this and a little more time spent during the development phase would have found a solution that would be better than what it presently is.

[engineertwin2]

But it isn't necessarily a dufus engineer - it could be a management approach, saying "hey, we've already got a cruise control module, install that one!"Common sense doesn't always play out when you get management involved. All I'm saying is that maybe it wasn't engineered at all. And maybe that wasn't an engineer's fault...sensitive on this subject, I am (as you can tell). But I'm tired of people blaming the damn engineer when it isn't necessarily his fault.I designed a floating helipad mount for a dam here in AZ. The mount had been designed to strict tolerances to fit within parapet wall structures. While out of the office for a day, my manager at the time approved a design change without my knowledge and all hell broke loose...All I'm saying is it isn't always an engineering decision that causes problems in the line. I'm done with this topic.

[djb383]

My bad, I apologize for my choice of words. My father-in-law, God rest his sole, was a brilliant engineer and I loved him as my own father. Again, sorry.