No Lock Up ???? Need Help

[turbo john FL]

THANKS IN ADVANCE FOR ANY HELP HERE WITH THIS PROBLEM I HAVE A FRESH REBUILD ON TRANNY INCLUDING NEW LOCK UP SOLENOID ALSO NEW PTS 9/11 TORQUE CONVERTOR . WHEN I FIRST GOT CAR BACK THE SOLENOID WAS INSTALLED 180 DEGEES OUT SO THE WIRES CAME IN CONTACT WITH THE PAN AND GROUNDED OUT ,I HAD LOCK UP BUT LOW MPH AND IN AND OUT . PULLED PAN REINSTALLED SOLENOID CORRECTLEY ALSO CHANGED THE 2 PRESSURE SWITCHES ON THE VALVE BODY WITH NEW GM PIECES . NOW I HAVE NO LOCKUP AT ALL . I HAVE CHECKED ALL FUSES IN FUSE PANEL SO I AM NOW STUMPED. NOT MANY GOOD MECHANICS IN MY AREA SO ANYONE WITH AN IDEA WHERE I SHOULD LOOK FOR WHAT THE PROBLEM IS I WILL BE GRATEFUL
THANKS JOHN

 

[ChrisCairns]

Take the car back out on the street....go past lockup speed (depends on the chip) and put your left foot UNDER the brake pedal and lift it up. It might just be that the brake switch is slightly out of whack.

 

[turbo john FL]

CHRIS IS THE BRAKE SWITCH TIED IN TO THE ECM CIRCUIT FOR THE LOCK UP COMMAND?? OR IS THERE A SECONDARY SWITCH I WILL TRY THAT THOUGH TODAY AND SEE IF THAT EFFECTS ANYTHING
THANKS JOHN

 

[ChrisCairns]

Originally posted by turbo john FL
CHRIS IS THE BRAKE SWITCH TIED IN TO THE ECM CIRCUIT FOR THE LOCK UP COMMAND?? OR IS THERE A SECONDARY SWITCH I WILL TRY THAT THOUGH TODAY AND SEE IF THAT EFFECTS ANYTHING
THANKS JOHN

Hmmmm, sorry I can't remember. And I'm too lazy to go look...lol.

I think though that it's one button that the brake pedal hits on, that switches the brake lights on through one circuit and breaks the circuit for the lu 'noid. But don't quote me...lol.

Did it work by the way?

 

[turbo john FL]

chris tried it yesterday and no luck still no lock up i lifted up on the pedal and also re adjusted the switch . but with no resolve . anybody with other ideas ??????????????????????????????

 

[ChrisCairns]

Well so much for the easy solution.

Do you have a scan tool so you can see it the ECM is commanding lockup?

 

[salvageV6]

At the trans. connector, key on, the purple wire pin A should have power on it through the brake switch and ECM/SOL fuse.

The tan/blk wire pin D gets grounded by the ECM pin A7 tan/blk wire at the ECM when lockup is commanded it gets grounded.

Will read +12 through the solenoid and purple wire otherwise.

You can force lockup at any speed by putting a GROUND on Pin F of the ALDL port, that's what a lockup switch for track use does.
It's also a tan/blk wire, I'd wire up a ground to one side of a switch and stick the wire in pin F of the ALDL and throw it when you hit 30 mph or so, it should lug the car down and lock up IF you have power on the purple wire, easy to test that key on in the driveway at the tranny.

Sometimes in my GN it won't lock up through the ECM but always will lock up with my added switch, there is a splice between the ECM and the ALDL port and the wiring to the tranny, haven't looked mine over yet.

 

[turbo john FL]

thanks salvage 5 i appreciate the help. i will check for power at the tranny in the morning and go from there
john