HELP! can't keep off the rev-limit/fuel-cut

[white2001s10]

1998 C5 vette LS1 A4
SD OL tune, but I don't think it makes a difference with stock tune either.

I'm using EFI-live for tuning & scanning,
trying to raise the shift points beyond 6300 RPM, and it goes into fuel-cut.
Raised rev-limits to 7300, still fuel cut at 6400 RPM ...WTF?
Several flashes at different settings... putting normal, hot, and cruise all at the same numbers, but no difference.

Once the car ran with the higher shift points perfectly and really liked the higher RPM, but the next tries (nothing changed in the tune) all hit fuel cut especially during the 2nd to 3rd shift.

I have tried several times, and looked through the tables and cannot find anything that seems like it would cause this.

I don't ask for help often, but this time I'm at a loss and need a hint at least.
Please throw out suggestions. Hopefully this isn't one of those "vette features"

[dbaxter_ss]

Where are you changing them,
Under Trans Calibration\Shift at RPM\Upshift ?

LABELS Selection
Parameters Value
{D0940} WOT 1->2 Shift RPM, Normal 5300.000000 RPM
{D0941} WOT 1->2 Shift RPM, Performance 5300.000000 RPM
{D0942} WOT 1->2 Shift RPM, Hot 5300.000000 RPM
{D0945} WOT 2->3 Shift RPM, Normal 5300.000000 RPM
{D0946} WOT 2->3 Shift RPM, Performance 0.000000 RPM
{D0947} WOT 2->3 Shift RPM, Hot 5300.000000 RPM
{D0950} WOT 3->4 Shift RPM, Normal 5300.000000 RPM
{D0951} WOT 3->4 Shift RPM, Performance 0.000000 RPM
{D0952} WOT 3->4 Shift RPM, Hot 5300.000000 RPM

or
Engine Calibrations\Rev Limiters

LABELS Fuel Cut-off Limiters in Gear (RPM)
In-Gear Cutoff Fuel In-Gear ReEnable Fuel
First Gear 6800.000000 6400.000000
Second Gear 6800.000000 6400.000000
Third Gear 6800.000000 6400.000000
Fourth Gear 6800.000000 6400.000000
Fifth Gear 6800.000000 6400.000000
Sixth Gear 6800.000000 6400.000000
Seventh Gear 6800.000000 6400.000000
Eighth Gear 6800.000000 6400.000000
Not In Gear 6800.000000 6400.000000
Reverse Gear 6800.000000 6400.000000

[white2001s10]

Shift points in the first one,
and rev-limit in the second one,
so both.
Shift point set at 6300
rev limit set at 7300
hits rev limit at 6400



edit: see since I can't get it to rev to 6400 or more, I had to lower the shift point down to 6300.
the shift points are working fine... or at least trying to. It's the rev-limit that's kicking in for apparently no reason.

[dbaxter_ss]

Strange? The A4 GTO I have setup with the rev limits at 6800 and trans cal upshift by VSS and have no problems.

Those are the 2 areas I know to change RPM limits.

[white2001s10]

I'm not sure changing the upshift to VSS instead of RPM would do anything. It already shifts fine based on RPM.

It just seems the PCM thinks it needs to cut fuel at the wrong time.

[dbaxter_ss]

Well its a vette, does it have ETC?

Or maybe even VSS failed RPM limit?

LABELS ETC Controlled RPM Limit (RPM)
Value
First Gear 9000.000000
Second Gear 9000.000000
Third Gear 9000.000000
Fourth Gear 9000.000000
Fifth Gear 9000.000000
Sixth Gear 9000.000000
Seventh Gear 9000.000000
Eighth Gear 9000.000000
Not In Gear 9000.000000
Reverse Gear 9000.000000


LABELS Selection
Parameters Value
{B2201} ETC Rev Limit Enable Disable
{B3330} Fuel Cut-off in P/N 6200.000000 RPM
{B3331} Fuel Re-enable in P/N 6199.023438 RPM
{B3332} Fuel Cut-off, Low RPM 41.992188 RPM
{B3333} Fuel Re-enable, Low RPM 50.000000 RPM
{B3301} Engine Overspeed Time Allowed 0.025000 Seconds
{B3322} VSS Failed RPM Limit Upper 6200.000000 RPM
{B3323} VSS Failed RPM Limit Lower 6199.023438 RPM

Do you have a log of this cutting out and the tun, I will take a look, another set of eyes may see something.

[white2001s10]

VSS fail = 7000 RPM

ETC limiter is disabled, and I'd see it on the scan if the TPS changed, and it doesn't. I do see a sharp lean spike on the wideband log when it hits fuel cut.

[white2001s10]

Ok well I lied, the TPS % does change from 99.6% down to 99.2%, and up to 100% sometimes, but since the change is so small I discounted it as a problem.
i worked on it all day today and failed to solve the problem.
The rev limiter either don't work, or it does work uncontrollably or almost randomly sometimes.

Shaka when the walls fell

[jfpilla]

Have you tried logging transmission converter clutch slip speed, Trans input speed and Trans output speed? See if it's slipping.

[white2001s10]

Have you tried logging transmission converter clutch slip speed, Trans input speed and Trans output speed? See if it's slipping.

I'm willing to try that too, but please tell me how that would make the limiter malfunction.
The limiter is now set to 7800 RPM, and the logs show the limiter cutting things off either at 6400, or 6000 RPM. There's no way the engine is spinning faster than that or I'd be able to tell.