Yes, 1997 was the last year for the 4T60E (vac modulator) trans. So the force motor table tables are not used.Originally Posted by mylittleblackbird
Russ Kemp
Yes, 1997 was the last year for the 4T60E (vac modulator) trans. So the force motor table tables are not used.
Russ Kemp
Good news is coming...
Today please...
Last edited by mylittleblackbird; 09-02-2008 at 06:32 PM.
Wow. I was pleasantly surprised by the last tune, Russ (revision D). It isn't where it needs to be, but it was definitely better than any other tune I've tried thus far.
As you can see in the WOT scan, the 1-2 shift flirted with the rev limiter but did not bounce as it had in previous tunes. It definitely hung between 1st and 2nd too long, but it is a marked improvement.
The 2-3 shift was even more impressive. It definitely shifted before the limiter. The scan shows the RPM topping out at 5500, but the dashboard suggested 5600-5700 before shift completion. Still, this was well before the 6000rpm limiter, which is the first tune that has not bounced the 2-3. You can also see that shift time for the 2-3 was lower than other scans based on the linear RPM graph.
The speedometer was really close but still displayed a bit of error at speed. 60mph indicated on the speedometer was actually 62-63mph on the GPS.
There are also driveability issues, such as a reluctance to hold TCC lockup while cruising at 65mph on the freeway. It seemed to disengage far too easily. Lockup in 4th gear also occurs at higher speed than it should (approx. 48mph if memory serves me).
Russ, whatever you did, it seems you're barking up the right tree! What are your thoughts?
Sounds like things are starting to line up! On this tune, I raised the speedo by 4%. Also lowered the part throttle, WOT & TCC lock/unlock speeds.
Once the speedo is accurate, then the shift speeds can be fine tuned.
Russ Kemp
This one was different, but I don't think it was any better. The 1-2 bounced off the limiter, though the 2-3 shows promise. I believe the 2-3 was completed by about 5500-5600rpm, but it was a sluggish shift.
Speedo needs to go back the other direction, perhaps half of the last change. When cruising the speedometer indicated 65mph and the GPS showed 63mph.
What do you think Russ? Do you feel like there is light at the end of the tunnel? Anything I need to physically inspect on the car for functionality? VSS sensors, other electronics, etc...
I've been following/learning from this thread & reviewing all the tune changes/logs. There is one thing I noted that I'm curious about. In the original post it is stated that the car has 3.06's with a different set of sprockets to achieve a FDR of 3.43. What I'm curious about is why the Drive Sprocket Ratio has been left at 1.00, relying instead on VSS pulses to correct the speedo? Just trying to learn what the reasoning for this is, & do you suppose that this may be a factor with the cars shifting performance?
Is it feasible that leaving the tire size, gear ratio, & VSS pulses stock, & changing the sprocket ratio to correct the speedo may improve matters?
Last edited by Shane Hewitt; 09-03-2008 at 05:45 PM.
On this tune, I lowered the speedo by 2%. Also lowered the 1-2 WOT & PT shift speeds.
Russ Kemp
Changing the sprocket ratio in the tune will set off the incorrect gear ratio code. Yet on this Bonneville, P0730 is set to no error reported. I cannot verify if that is stock.
Russ Kemp
If the P0730 code was set that way in the factory tune I posted then I would assume it was a stock setting. I have never touched that error code in HP Tuners. Based on everything I read on this forum I was under the impression that P0730 should not be disabled. If it ought to be enabled I can do so.
Thank you for giving the tune another try. I'll scan later this morning and report back ASAP.
*crickets*
My parents have been town and we haven't had time to try the tune. They leave tomorrow morning, after which time I'll be able to report back about the results. I'm definitely still trying to get this thing working.
BTW, the car loses TCC lockup after it locks and unlocks a couple of times on the freeway. It set a Check Engine light, which I will scan today or tomorrow.
Russ your pms are full. Coul you email me at [email protected] when you get a chance?
Factory Stock 97 SS M6 13.51 @ 104.3 mph
Stock Longblock LS1 w/ 233/238 P.S.I. Cam
10.81 @ 126.9 Full interior, six speed on 275 radials, a decade ago
'99 TA trunk mounted 76mm 6 Liter
9.0s in '09 @ 153 MPH
Turbo 5.3 Volvo 740 Wagon
32psi and still winding out 5th on the highway somewhere
So what's going on with this trans issue?
This car has had its share of problems since I've known Ben.
Looking forward to seeing this get resolved.
Best 60' = 1.716
Best ET = 12.186
Best MPH = 112.98
Finally got some scanning done!
First of all, tune revision "E" set a P1870 Transmission Component Slipping code after extensive freeway driving. We ran into the same problem after the first tranny swap almost 2 years ago. After cruising on the freeway and having the TCC lock and unlock multiple times (because of typical freeway traffic and letting off the accelerator) the car set the code and disabled TCC lockup. I had driven about 30 minutes to the airport, and on the return trip I noticed that the check engine light had illuminated and the TCC was no longer locking while cruising. To be honest, I do not recall how we got around the problem the first time.
After retrieving the trouble code, I flashed tune revision "F" and went out for normal scanning. The speedometer seems to be almost perfect now, certainly within the tolerances of gauge error. At the most it is .3 to .5mph off at 75mph, which is negligible in my opinion.
The 1-2 shift still bounces the rev limiter. The 2-3 is shifting before the limiter, though still sluggish. You can see this in the scan entitled "WOT".
I attempted to recreate the conditions which caused the P1870 in revision "E", but this tune did not exhibit the same issues. I took a 20 minute freeway drive and put the car through 15-20 TCC lock/unlock cycles, but the CEL did not illuminate and the TCC continued to lock while cruising. You can view part of this drive in the scan entitled "Cruise & Downshifts". The TCC seems to unlock too easily when under light cruise throttle, but other than that it works fairly well. I also noticed the TCC does not seem to be locking in 3rd gear, which is something I would like to happen.
Where do we go next, Russ? As always, I am extremely appreciative of your expertise in this matter. Thank you.
Were getting very close now! I've had a few 3800 SC cars that in order to have a 5750 RPM 1-2 upshift, I had to enter 5450 RPM. On this tune, I lowered the WOT 1-2 shift RPM by 5%.
The WOT commanded 3rd gear is at 5438 RPM, so I lowered the WOT 2-3 & 3-2 shift speed.
As for the TCC, the scan shows that there is still over 200 RPM slip when cruising. Try locking the TCC with the scanner.
On my V6 tunes, the TCC won't lock until 4th gear, unless you select manual 3rd.
Russ Kemp
Got some scans with revision "G":
The 1-2 does not bounce off the limiter now. The shift seems to be commanded at 5100-5200rpm but does not complete until 5800-5900rpm. The shift is also extremely sluggish, which has me concerned because as far as I know there is no way to electronically tune shift time/firmness with a 4T60E. Check out the scan entitled "WOT" to see what I'm talking about.
Part-throttle shifts and cruising are still sloppy. Part-throttle shifts are also slow, and I can feel a distinct disengagement/re-engagement as the shift is commanded and executed.
I also lost TCC lockup on the freeway after a long cruise. The CEL did not illuminate, but after a few more cycles of the same behavior it most certainly will. I was able to capture the loss of lockup in a scan entitled "Long Cruise". At the beginning of the scan you can see the TCC is locked while cruising, and at the end of the scan you can see the TCC is off. There also seems to be spikes of mystery KR that pop up while cruising, but this is certainly another can of worms.
I did another short scan of the car while the TCC had disabled itself. This scan is entitled "Short Cruise No TCC Lock".
EDIT: I attempted to lock the TCC with the VCM Scanner while driving, but for some reason the button was greyed out.
Do they make an adjustable modulator that you can use to bump the pressure up for the 4T60E like you can do on the non electronic T350/T400 rear drive transmissions?
I just found that the FWD or transaxle button is not selected by default on your tune! Once it is selected, the normal tire size & gear ratio fields appear.
On this tune, I went over all the shift speed & TCC tables, and set up the gear ratio as 3.43.
I'm positive that the solution is near!
Russ Kemp
Yes, the modulator I have is adjustable. The problem thus far is that the shifts are slow and sluggish even when the modulator is adjusted for maximum line pressure! Normally I would be concerned about an assembly error in the transmission, but in my case this is the THIRD tranny that has exhibited the exact same shift behavior. Methinks it may be a different issue, i.e. tuning or electrical.
Well crap, I could've told you that!
Oddly enough, no matter how you save the tune, every time you reopen it in the Editor the FWD/Transaxle button is reset. Does this have any bearing on our problem?
I'll try the new tune tomorrow and report the results.
Reply With Quote
