One thing I noticed is that the TCC apply 2nd in the performance tables were all set to 0. I don't know if that has any bearing on it, but it's something to look at I think.
One thing I noticed is that the TCC apply 2nd in the performance tables were all set to 0. I don't know if that has any bearing on it, but it's something to look at I think.
I need a 100% stock tune (with no changed tables), and post your latest tune. Then I will set up the trans & speedo tables &
apply them to the latest tune.
Russ Kemp
The 100% stock tune is the one PDXGTP uploaded entitled "1997 Bonneville Stock Ben 33008". I have reattached it here, as well as my current tune entitled "97 Bonnie Mod 8-5-08".
The current tune is the same one that I posted earlier in this thread for people to review. The speedo/shift settings are obviously wrong, but the engine tuning is in the ballpark.
If you need anything else, please let me know and I'll get it to you ASAFP.
Just an FYI, the 97s with the 4T60 have a bit set in their calibrations set to 0. It is referenced as "Shift Quality Controlled by PCM" or something similar.. All have certain shift settings zeroed as noted above.
97 Grand Prix GTP (not going to bother listing mods in detail) 1 messed up 97 PCM with about 30-50% of a 2003 calibration and parts of a few others.
big news 1,
Try this trans tune. I made the trans & speedo changes to your latest tune.
Russ Kemp
I'll try the tune as soon as I get off work later this morning. Any specific scan data you want to see?
Include the trans output rpm in your scan. And verify that the speedo is accurate.
Russ Kemp
Well, I just uploaded the tune and scanned the car, but I managed to close the damn scanner before saving the log file. Grrrr...
From my standpoint, the car feels exactly the same as before. Part throttle shifts are a bit on the sluggish side, and the WOT 1-2 shift bounces off the rev limiter before it decides to try and shift gears. I know that for a fact. This car is possessed...
I will go out and re-scan within the hour so I can post a log file.
Is there any way that the transmission could function independantly from the PCM? Some sort of mechanical safe mode when no input is received for certain solenoids? Or, say a sensor simply isn't working, so it defaults to a preset number in the PCM that is no longer accurate?(and can't be seen or accessed?)
Got the scan data. BTW, I do not own a handheld GPS to verify my speed. I'll have to borrow one for speed verification. Not sure on the timeframe for this.
I've attached three scans. One is WOT throttle through the 1-2 and 2-3 shifts. Another is cruising at 50mph (indicated on speedometer) in 4th gear with TCC locked. The third scan is normal acceleration from a stoplight from 1st through 4th gears.
You can see the awful shift behavior in the WOT scan. It bounced off the rev limiter (5950rpm) two or three times before it shifted. Oddly enough it shows 2nd gear selected even though it is revving up against the limiter.
In the cruise scan you can see that it is showing ~175rpm of TCC slip when fully locked. This differs from the previous tune I was using, in which we were able to get the TCC slip to read ~0rpm when locked.
Enough typing... I'll let you guys draw unbiased conclusions. Overall though the car still felt really sloppy. Driveability seemed a bit worse than the previous tune I was using (no offense Russ, just trying to give accurate commentary). Let me know what you guys think.
EDIT: Still curious to hear thoughts about electrical gremlins... Would a bad ground/low voltage condition cause funky issues like this? I've got a sneaking suspicion there's more to this story.
Looking at the scans, the trans output rpms are matching with the revs/mile in the editor. And in 3rd gear, the trans calculated gear ratio is correctly reporting 1.00, and in 4th gear, the reported gear ratio is .703 (very close to the actual .705 4th gear ratio).
In this tune, I lowered the wot shift speeds, as your car was ~5600 before 2nd gear was commanded, and 5674 before 3rd gear was commanded.
You still need to verify the speedo accuracy. And scan for any DTC's.
Russ Kemp
What I can see is that it's telling you to shift at WOT(noted in the cruising scan) around 35-37 mph, I suspect closer to 37 than 35. RPM is between 5530 and 5700... from there it takes about .4 seconds to start calculating the gear ratio, and .8 seconds to complete the calculation. What all that means? I'm not sure. I'd like to think it could be used to conceive some idea of what is going on here. Also, is this TCC slip RPM accurate when in lock-up?
Last edited by mylittleblackbird; 08-28-2008 at 05:00 PM.
Loaded the new tune... attached are the scan results.
Basically, the car shifted exactly the same as the first tune. It's like nothing changed. I also compared speed with a GPS and found the speedometer to be slow. At 45mph on the speedo the GPS indicated 50mph. At 65mph on the speedo the GPS read 72-73. The scans for this tune are entitled "Normal Accel + Cruise" and "WOT".
As a comparison I loaded my last tune, which is an automatic scaling with 3.43 entered as the calculated gear ratio and stock tire height. With this tune the speedometer appeared to be within 1mph at all speeds, but shifts were still awful. I did a scan with WOT acceleration and high speed cruise. This is entitled "Old Tune WOT + Cruise"
Opinions? Russ, what do you think is going on with this cursed thing?
Have you tried making your Full Throttle Shift Speed Normal & Full Throttle Shift Speed Performance match?
The reason I ask is that it appears that your car starts bouncing off the rev limiter at around 39 mph, & once the car finally sees 40 mph (the speed in the performance table), the upshift commences.
It appears that the 2-3 upshift has the same issues.
Worth a shot for the time it takes.
I changed the speedo to read 10% higher. Looks like your WOT 2-3 shift was at 5550 rpm. Also lowered the force motor tables to firm up the shifts.
I also copied the normal shift speeds to the performance & hot tables.
Russ Kemp
Russ, just curious. How does the force motor apply in the vac modulated tranny? I was under the impression that the modulator handled shift pressures? I'm not intending to come off as rude. It's as sincere a question as they come.
Finally got the tune in the car. As you might have expected, results were largely the same. For some reason the transmission is not physically shifting after the PCM commands the shift. In all the scans I've done you can see the PCM reads 2nd gear after 5400-5500rpm but the shift has not physically occurred. The speedometer was also incorrect, this time by a larger margin. Russ, the correction you made might have been in the wrong direction. When cruising at 50mph indicated on the speedometer the GPS showed 62mph.
I have attached the usual cruising scan and WOT scan.
I should also mention that when pulling up the DTC function of the HPT Scanner it says no trouble codes detected.
I now need to determine if the shifting issue is mechanical or electrical. Russ, do you have any input on whether this might be caused by an electrical problem such as improper or poorly-regulated voltage? As mentioned before the car has some sort of electrical gremlins that I haven't been able to track down yet.
Please, if anyone has an opinion or idea I would be most appreciative. Russ, I am particularly interested in what you've been able to glean from the last few scans I have posted. Thank you very much for the help so far!
Sorry, I when the wrong way on the speedo! Hopefully this tune will get the speedo correct.
It is normal for the WOT gear change in the scanner occur several mph before the shift rpm is met. Once the speedo is correct, the WOT & PT shifts will be correct.
As for the force motor table, I'll check my ALDATA to see if there is a pcs in your transmission.
Russ Kemp
Last edited by Russ K; 09-02-2008 at 12:14 AM.
Interesting... I didn't know the shifts were so dependent on speedometer accuracy. Still, why doesn't my original tune (the base tune you are using for your modifications) work properly since the speedometer is correct in that tune?Originally Posted by Russ K
I'll try the new tune when I get off work tomorrow morning.
PCS is a 4T65 thing. The 4T60 uses a vac modulator.
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