[blackbronco]

I've had my 2002 STS for a about a year now and i've noticed something strange with the rev limiter.

While the stick is in D, If the car is in 1st gear, and I make the traction control engage, if I stay on it WOT the car will bounce off the rev limiter before shifting into 2nd. This will happen ONLY if the traction control engages. If I back off the throttle just a bit it will shift around 6200.

I checked codes and they are both History:
RIM B1328 - System voltage greater than 15.9
TTM U1016 - Loss of communication with PSM

I dont think these codes have connection with my issue.


Is this a normal quark? Or and I just the lucky one?

 

[Submariner409]

Depends on exactly what is happening. Using the TC on/off button the console should have no effect on either shift point or rev limiter. Normal WOT shifts occur at about 6300. There is also a rev limiter set at 4,000 rpm in N or P.

IF you punch it and incur wheelspin a couple of things may happen - TC may or may not engage, limiting wheelspin, and/or Torque Limiting may engage, dropping 4 cylinders and killing engine power delivery - the engine power dies radically and you would never reach redline.

If you turn TC OFF - message in the DIC - you should be able to incur wheelspin, but then there's a point at which Torque Limiting takes over. Getting a decent launch on these cars is a delicate maneuver. Practice.

If the engine bounces off the limiter before the 1 - 2 shift, suspect the 1 - 2 or 2 - 3 shift solenoid pack on the side of the valve body. A fairly common problem with our series of 4T80E transmission - there's a new (re-design) solenoid pair and reinforcement bracket in the field - a GM part - I had them installed when my Cadillac dealer did a fluid exchange in 2007. When was the last time you had a fluid exchange, and did you install the new DEXRON-VI synthetic fluid ??

FWIW, On a perfect launch you should get some wheelspin in 1, a chirp to 2, and depending on road surface, a slight chirp to 3 (that comes at over 80). Shifts occur at WOT 6300 rpm or so. The car will do well over 130 in 3rd.

 

[Ranger]

Why are you going WOT in 1st gear anyway? Use 2nd.

 

[Submariner409]

In this case, I assume the WOT is being used for maximum acceleration to max speed - put it in 1, 2, or 3, stick your foot through the firewall until you run out of runway, rpm, or vehicle speed limiter.

Mine will do 143 with the stick in 1 - foot to the floor. Fastest yet (GPS), and I'll never try it again - reflexes slowing too much.

 

[blackbronco]

I should have been more clean on this. My situation is NOT during the WOT procedure talked about so often, that i do frequently and never have the rev limiter issue.

Say im driving around normal. I slow down and take a turn onto a winding street. I put my foot to the floor! Car down shifts to 1st gear, breaks the tires loose. Traction control steps in for a brief second (DIC says "Traction Engaged) At this point if i leave my foot to the floor I hit the rev limiter and the 1-2 shift.

If i got through the same situation and roll onto the throttle not allowing traction control the engage it shifts fine.

Sub- shortly before I bought the car the head gasket was done, block studded by a local shop that seems to know northstar's fairly well. The torque converter clutch solenoid was replaced at the same time. Im not positive what else if anything was done to the trans at that time. I was told OEM spec fluid was put back in.

 

[RippyPartsDept]

i'm pretty sure the updated shift solenoids with the bracket were factory parts by 2002

 

[blackbronco]

Did I stump everyone?