I posted this in the Computer/Diagnostics forum in case it is a tuning problem on my part. Mods are in the sig. I ran this stall converter with my old setup and everything was fine. The difference is, I sent the converter back to Precision and had it rebuilt, they said they put a different rotor in it to help the turbo spool (maybe this is the problem?), and I put it in one of CPT Frank's race transmissions....here's the problem:

I've tried lowering the mph values in ALL the transmission tables, along with turning off the switch that allows the TCC release at small TPS %...I'm getting 10mpg with mostly highway miles and I do believe this is much of the problem. Everytime the gradiant on the road changes, the TC unlocks, free revs to 3100rpm and then slowly locks up and then the car accelerates back up to cruise speed. I can be on a flat road, or going down a hill with OD locked, and if I want to accelerate from 55mph to 56mph by increasing throttle from 10%-11%, the thing unlocks, revs to 3100rpm, locks up and then accelerates. WTF?

Thanks guys/gals

 

It does sound like a tuning issue however there are other things to look at , I know that if the PCM detects engine missfire under load it will unlock the converter

 

Thanks, Performabuilt. I was just reading in your thread titled "4l60e lock up issues and probable causes..." I came across that lastnight and it gave me a pretty good starting point for fixing it. My plugs are in poor condition (pretty black...I did fuel foul them a couple months ago when I ran car with coolant temp sensor unplugged).
However, it is my understanding that OBDI (which I have) can not detect misfires since it does not have the CPS. So, what then could tell the converter to unlock?

I've checked and rechecked the tune. I also looked at the data log from last year and found that the converter stayed locked up in 4th/OD when it was suppose to. I also found that according to Datamaster, the computer is commanding the TCC be engaged even while it is actually released. On the contrary, it is releasing when it is suppose to release....but it's also releasing when it's suppose to be engaged according to the PCM.

Either way, I'm going to change the spark plugs and fuel filter while i'm at it even though the fuel pressure is fine at cruise and my fuel trims are also good.

 

I am not sure in that year PCM but I certainly would try the plugs and get the engine running good and work from there,
Let us know how that turns out and if needed we can check some more stuff . There are many possibilities