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View Full Version : Trans shifts with out meeting the commanded VSS and RPM



odd boy
November 3rd, 2008, 11:52 PM
hi,

I am facing a problem with tuning camaro 99. The trans just got overhauled few weeks ago, if the trans on "D" position and the it is under WOT condition, it shifts to 2 at 5000, then to 3 then 4 in few seconds (with out meeting the commanded VSS and RPM).

Any suggestion gents?

4198

joecar
November 4th, 2008, 04:28 AM
Do you have any logs...?

joecar
November 4th, 2008, 04:33 AM
What RPM does it do 2->3 and 3->4...?

Try setting the WOT 3->4 RPM higher, say 6600 or 6800.

What stall speed is your converter and what HP & TQ does your motor develop...?

odd boy
November 4th, 2008, 04:38 AM
here is one. If you like I'll call him to repate it and tell me what u want me to log more than the rpm, tps, VSS.

4199

odd boy
November 4th, 2008, 04:42 AM
What RPM does it do 2->3 and 3->4...?

Try setting the WOT 3->4 RPM higher, say 6600 or 6800.

What stall speed is your converter and what HP & TQ does your motor develop...?

The car doesn't hold in gear it goes from 2 to 4.

the race converter has just been removed now it is with the stock one.

The car does 380 hp and 395 tq

joecar
November 4th, 2008, 05:22 AM
It looks like it bounced off the rev limiter when traction was lost at the high end of 1st gear...

(it looks like 1st gear to me... but the GEAR pid wasn't logged).

Either traction was severely lost (50mph -> 80mph in 0.2s) or the VSS sensor is faulty and/or picking up noise... I don't think you lost traction since the RPM jumps up only 100-300 rpm... I think there's a VSS problem.

Then it looks like it shifted 1->3... when VSS shot up to 80mph, the WOT 2->3 MPH condition was met so it shifted into 3rd.

It looks like it never went into 4th during WOT (it went into 4th after the throttle was released.