goldylocks

iTrader: (4)

Hi guys,
I have a problem with a LT1 corvette. At WOT, it'll get to about 5k RPM and just hang there. It feels really down on power. Other than that the car drives just fine. I was thinking it was perhaps a fuel issue. primed it will go to about 35 psi and slowly drop. Running it is at about 35 psi and at WOT it jumps to about 40 psi. Is this normal?

fbody_brian

Valve foat?
I wouldn't think fuel.

97lt1camaro

iTrader: (3)

Sounds like the 3/4 clutches are worn out. Common problem for the 4l60e.

goldylocks

iTrader: (4)

So the whole fuel pressure thing is fine? Any way I could verify valve float? I don't think it's the 3-4 clutches it does going from 1st to 2nd or 2nd to 3rd I believe. I wasn't thinking it was a transmission issue because during regular driving it shifts fine, no slipping or anything.

myltwon

iTrader: (1)

How's vacuum on the engine?

goldylocks

iTrader: (4)

I'm not really sure how would I check?

NewOrleansLT1

My car did that before, come to find out I had burnt clutches.. Then my sprag gear went out shortly after.. Got it rebuilt and all was well..

myltwon

iTrader: (1)

You need to either purchase or rent a vacuum gauge and hook it up to a vacuum port/line and verify pressure.

Another easy check is fluid level, low trans fluid level will cause it to not shift under WOT

VoyagerCamaro

My old 95 z28 was an A4 before I did a M6 swap, but it always did exactly what you were talking about. Didn't bust, didn't skip, just seemed like it stayed at redline rpm forever before shifting.

Critt3r

iTrader: (1)

Trans issue imo.

fbody_brian

If it was the 3/4 clutch pack there wouldn't be issues with the 1-2 shift, just 2-3, right?
Also, if the trans was slipping and not shifting you would be hitting the rev limiter, well above 5000 rpm, right?

Do you have a way to get a datalog?
That would show you if the pcm is commanding the shift, and a better idea of what is going on.

Critt3r

iTrader: (1)

Mine was doing this exact thing. It would not shift at WOT so i had to back off the gas to let it shift then get back on it. I dont remember what it was, but it was a trans issue. I think 3/4 clutch pack.