rickou812

iTrader: (10)

History: 1995 obd1 383 Lt1 tuned by mail PCMforless. Very happy with the tune over all, but have one issue I can not figure out.

The torque converter is locked on the 2-3 3-4 shift at part throttle and WOT. I can prevent it from locking by holding the brake during the shift.

I have emailed back and forth with Brian at PCMforless and says there is nothing in the tune that would cause this. I think it has to be tune and not mechanical due to the fact it will not lock if the brake is depressed.

Can anyone shed any light on this situation.
P.S. NOT the car in the sig..

Thanks,
Rick

1320

iTrader: (6)

Im not sure about this at all. I havnt been under the dash of an lt1 car in awhile. There might be 2 or 3 switches on the brake pedal though. One might be faulty....causing this. Seems like a possibilty, that the lock up solinoid is getting grounded un intentionally in wiring somewhere. You can probably prob the wires with just the key on, since it wont lock up in 1st, even if its energized. Double check that though, with someone else. I d call rossler or equivalent.

sreve

iTrader: (3)

first place i'd look see pic.

seems unlikely he missed it

brake switch keeps power to pcm and interupts it when brake pedal is depressed

rickou812

iTrader: (10)

Here is what I have:


I wonder if checking the "Upshift Turns TCC off" will fix it?

2xLS1

iTrader: (25)

That is unchecked on stock calibrations so I doubt it. It is really unusual to have TCC lockup in second. What do the normal lock up tables look like. What you posted is the WOT lock up table. Or just attatch the whole bin.

rickou812

iTrader: (10)

Here is the whole tune file. Change the file extension to .bin or .lt1 to before opening. Had to change due to the forum upload.

rickou812

iTrader: (10)

It is only locked on the 2-3 shift if I am over 40 mph part throttle or WOT shift which occurs around 83mph.
It is noticeable even with light throttle 3-4 shift which occurs around 50mph. When shifting into 4th it bogs the engine. This engine has a pretty large cam and a 3600 stall converter, so it quite obvious when it is locked..

2xLS1

iTrader: (25)

I keep getting an error saying I need Def $Ef to open the file. If I tell it to proceeed any way the data in the tables is whacked. I'm using TC v2.26 and $EE vCY. And yes I changed it to .bin. And I would think for it to be locked on the 2-3 shift it would have to be locked in 2nd before the shift is commanded.

rickou812

iTrader: (10)

Not sure why, but it does that on mine too if I change it back to a .bin file, but seems to work if changed to a .lt1 file.

Try the .lt1 extension. I think I may have "Saved as" .lt1 when I could not upload the .bin Then noticed that the forum wouldn't allow .lt1 upload either..lol

Also note, I already made changes to the "TCC WOT Force Lock" table but have not tried it on the car yet. The tune that is in the car reflects the screen pic I posted above.

sreve

iTrader: (3)

.lt1 seems to work.
I did not see anything in the tune that would cause it. Interesting though the B-body
cars seem to have the box checked and not the F-bodys hmmm...........
There are several differnt BBCs though, maybe that will fix it.

RamAirRocket

iTrader: (1)

Old thread I know, but good to document....

The .LT1 vs .BIN (tunercat) is simply the E Side first in the .LT1 and the T Side first in the .bin (tunercat).

So with some hex editing you can make a .LT1 a real .bin or a .bin a .LT1.