Help w/ strange TC/Shift issue with Fuel Sipper tune

***cleatus12r*** · #1 Sat, April 25th, 2009, 11:20 AM

DJ,

I went out and drove it today. First off.....wow. I'm glad that everyone is entitled to their opinion. It's not a bad program, but it's definitely not for me.

Anyway, I was able to duplicate what I think you are feeling....it did it once for me.

Without knowing exactly what to expect and when to expect it, my first instinct is that as the 4-3 downshift is occuring, the torque converter is unlocking. That's normal. The bump you feel after that is the TC locking back up for 3rd gear since you're still at a road speed that allows TC lockup in 3rd.....but just barely. I think it happened at 37 MPH (indicated) up a small incline, low load, and slowly losing speed. It did "double bump" so to speak.

What needs to happen here? Either the 4-3 shift needs to occur earlier (higher speed), later (lower speed), the TC apply rate needs to be slowed down to take away from the "jerk" feel, or the TC relock time after the 4-3 downshift needs to be eliminated.

Raising the 4-3 downshift speed would allow the transmission to downshift before the engine gets to 1200 RPM and help by not transferring as much torque during the downshift. Lowering the downshift speed would allow a 4-3 downshift without an attempt to relock the torque converter in 3rd.

I would do a combination of a few things. I would change the relock time after 4-3 downshift to something rediculously low like .13 seconds. This will get rid of the perceived "flare" and then jerk on relock. I would also raise the 4-3 downshift speed by a couple MPH.....it's not really doing you any favors having it unlock at 37 MPH. You're also right about the harsh TCC apply. Since it's a file meant for economy, it's not meant to be "hogged on" and therefore very low APP is usually used. I'd lower the TCC apply duty cycle a bit in the lower load ranges too.

***cleatus12r*** · #2 Sat, April 25th, 2009, 11:27 AM

DJ,

This is a derailment....

I liked the Fountain area a lot. I've ridden my bike (crotch rocket) from Colorado Springs to Fountain a couple of times. It's one of the sweetest rides at moderate speed (when traffic allows). It compares to Wolf Creek Canyon near Helena here in Montana.....only CO has more traffic.

Beautiful country.

I couldn't imagine a 7500+ lb. Excursion with 3.73 gears, 35 inch tires, and these really early shifts at 6000 ft. I had a hell of a time one year I went to Colorado Springs in my 95 PSD. I was only running 35 inch tires, 4.10 gears, and a Big Hoss chip and that thing was a TURD.....even though it was better than average here at 4000 ft. Having no air is a real handicap. Sea level would ROCK.

soutthpaw · #3 Sat, April 25th, 2009, 01:10 PM

I just sent ya an email with the AE datalog I did this AM.. I even have a video of the instrument cluster on my blackberry but need to convert to play it
had to zip the file up to load it into the thread but at least Bill or anyone else can see it too that way

here is the cut and paste text
I monitored shift solenoid 2 as it shows "0" when in 4th and "1" in 3rd gear.

between about point 72 and 168 can see 2 sections where its got a constant speed and stays in OD but the RPM keeps fluctuating between about 1500 and 1000-1100 caused by the TCC locking and unlocking and the speed is constant around 40-41 mph throttle is running about 23%

Let me know what ya think, had a chance to get this data this am
Thanks DJ

OH I couldn't duplicate the effect in 60, 100 or 140 tunes either....

***cleatus12r*** · #4 Sat, April 25th, 2009, 01:46 PM

DJ,

Wow. Yeah. I see that. For some reason, the TCC isn't being commanded on....when it SHOULD be. Weird. I just drove mine again to see if I could get it to do what your datalog showed. Nope. Mine doesn't do it.

As far as your shift solenoid "issue" goes, there are two shift solenoids in the transmission that control the 4 gears. They work like a logic table. For example:

1 off, 2 off = 4th
1 off, 2 on = 3rd
1 on, 2 off = 1st
1 on, 2 on = 2nd

This goes along with what your AE showed you....SS2 "0" (off) in 4th and "1" (on) in 3rd.

If this parameter is changing when your TC is acting up, then you have a correlation issue between 3-4 and 4-3 shift points.

That's a neat software package you have there, DJ.

EDIT:
I see that the SS2 value changed at frame 143-ish. The TC was acting up before that..... Hmmm.

soutthpaw · #5 Sat, April 25th, 2009, 02:22 PM

Yeah its really strange. I sent Bill a PM so hopefully he will jump in again when he gets a chance as it's "his" tune... before I start changing stuff...... That's the first time I have used the AE software so pretty cool. and Being a CSV file anyone can look at the data in spreadsheet form without needing the AE software which I though was pretty cool instead of being a propitiatory format...
It all runs of my Sansung NC10 netbook which makes it real convenient to use

here is the video mataches to the 120-140 range of graph
Video of RPM surge

***cleatus12r*** · #6 Sun, April 26th, 2009, 01:52 PM

As far as any opinions go on this....

I got it to act up in my truck.

It shifted fine and correctly up until 4th gear and would hold 38-40 MPH all day and not have an issue. Once the speedometer hit 37, the torque converter would unlock and then start it's lock/unlock sequence.

Returning the 3-4 and 4-3 shift tables to normal (stock settings) gets rid of all issues with the shift....and it still shifts rediculously early. The thing to keep in mind is that the tune makes the accelerator pedal far more responsive than stock so the TP a/d is going to be lower for any road speed anyway so the transmission will shift earlier than stock all things considered.

For all intents and purposes, correcting for tire size and leaving the 3-4 and 4-3 shift parameters the same as stock would probably work just fine. Between us, another well-known tuner doesn't change the shift points at all for his "economy" tunes. The stock settings with a more sensitive APP makes the transmission shift early too.

soutthpaw · #7 Sun, April 26th, 2009, 10:25 PM

Quote:

Originally Posted by cleatus12r

As far as any opinions go on this....

I got it to act up in my truck.

It shifted fine and correctly up until 4th gear and would hold 38-40 MPH all day and not have an issue. Once the speedometer hit 37, the torque converter would unlock and then start it's lock/unlock sequence.

Returning the 3-4 and 4-3 shift tables to normal (stock settings) gets rid of all issues with the shift....and it still shifts rediculously early. The thing to keep in mind is that the tune makes the accelerator pedal far more responsive than stock so the TP a/d is going to be lower for any road speed anyway so the transmission will shift earlier than stock all things considered.

For all intents and purposes, correcting for tire size and leaving the 3-4 and 4-3 shift parameters the same as stock would probably work just fine. Between us, another well-known tuner doesn't change the shift points at all for his "economy" tunes. The stock settings with a more sensitive APP makes the transmission shift early too.

Thanks for your work and incite on this.. I sent you an email too. After I saw where it was shifting I wondered about the anticipated shift setting that starts at 1500RPM. Also even with the tire size corrected it still takes more torque to turn the larger diameter tires regardless of the speed. So it was not the Torque reduction issue right as the low throttle position wouldn't put excessive torque to the tranny in the first place...
Ok looked at the difference in upshift and its about 6mph difference.. I could just shift the lower half to stock and let the second half of the throttle from 512 to 1023 slide back to the lower shift points and see how that does...
Did you end up removing or changing the TC lockup or relock delay?

soutthpaw · #8 Fri, May 8th, 2009, 04:03 PM

I am looking forward to our trip to CA later this month so I can see how the tunes feel at sea level... That way I will have a better reference when I get back to the mountains and do some more tuning.... Actually the settings now are pretty good for easy driving.. I have the 100 and 140 on either side of FS position now so Real Power is not far away...

***cleatus12r*** · #9 Fri, May 8th, 2009, 04:23 PM

Quote:

Originally Posted by soutthpaw

I am looking forward to our trip to CA later this month so I can see how the tunes feel at sea level... That way I will have a better reference when I get back to the mountains and do some more tuning....

HA HA

You'll get down there and not want to get back to your no-air-having home. I've been to sea level with a couple of my vehicles. It's hard to believe how well they run down there.......

Then I have to come back and relearn how to live with my gutless turds.

soutthpaw · #10 Fri, June 19th, 2009, 01:50 AM

Well I am starting to find my way back on the forum after my trip to the UK and now in CA. Question for Bill, Just wandering if you got a chance to look at the fuel sipper tune and make any changes yourself as several of us seem to have a similar issue with the TC lockup that I started this thread about.

Silly me, thought I might actually get some time to work on my tunes while on "vacation" anyway just changed my Tire size setting so gonna go to WalMart tmw and have the tires installed there because I can get the lifetime balance deal... The tire I got from a local Remington distributor at a killer price but they are always busy for installs and they only do static balancing... 4 tires wer $509 out the door..