What does your scangauge show for EOT's? The PCM will keep the TC unlocked when it thinks the engine is cold... I am also curious what you're seeing on the scangauge for boost and backpressure numbers. I am postulating that the MAP and EBPS sensors have some to do with the TC lockup as well.

 

Good luck Glenn to your long journey home. When you get home and have a minutes, could you point me to the right direction to find a TC lockup switch write up? Or, if anyone else here is as knowlegable on this topic.

 

Torque Converter Lockup Switch and LED
The PCM controls the solenoid on the torque converter. When it is time for the TC to lockup, the PCM communicates to the solenoid to lock up the torque converter.

Locate the 12 pin oval-shaped connector on the passenger side of the transmission. It is connector C1048 and runs over the transmission to the driver’s side and up to the PCM. You are looking for the purple w/ yellow tracer (it might look like a blue with orange tracer. We have looked at SEVERAL trucks and they all look similar) wire coming out of pin 4 on the 12 pin connector. This is the wire that controls the lockup of the torque converter. Tap into this wire with a piece of 16-18 gauge wire and run into the cab through the firewall. Be sure to install a rubber grommet when routing wires through the firewall so the wire doesn’t rub through.


The switch can be installed without the LED indicator and the LED can be installed without the switch. Run a ground wire to one side of the switch and connect the other side of the switch to the wire you ran into the cab from the transmission. When the switch is flipped it will ground the signal from the transmission and lock up the torque converter. Connect a 12Volt wire to the hot side of the LED and connect the ground side of the LED to the wire you ran inside the cab from the transmission.

 

RÖENTGEEP
Thx a lot for the instruction. It sounds very straightforward. I'll try to get it done soon. Erwin

 

you are welcome. Anytime.

 

Thanks Nate, EOT reads about 215*. The boost will vary alot depending on the load I'm giving it, I can see up to 20psi for a long time with my EGT's at 1200*. Backpressure I don't know, I've never looked at that. What's it called on the scangauge? A couple of years ago I bought a new map so I think its OK.

eyyu, I'm sure glad I installed a toggle switch for the TC lock. It sure is coming in handly. Thanks Jose for helping him out.

 

https://www.ford-trucks.com/forums/6...l#post10906711

fyi; be sure to unlock your converter before downshifting to 3rd under load,or you could find yourself with a cracked flex plate.
better to let the pcm handle this job imho,but a lot of people like a switch.

 

This is probably a dumb question, but you are applying sufficient throttle right? The only reason I ask is that if I accelerate gently (I thin it is below 30% throttle application) with the stock tunes, the TC won't lock until I either get in the peddle (above 30% throttle) or it shifts to 4th. I would imagine that is different since you're running a towing tune, but that's the way mine does with stock tunes.

 

Even if I'm running around light Nate, I ALWAYS had the TC lock inbetween 3 & 4, even at real light throttle. In the back of my mind I thought I had a 5 speed, LOL. So, when this started I noticed it right away, "what's going on, I have a 4 speed now"??

FORDF250HDXLT, thanks, good advice!

 

My thoughts are flex plate and heres why------------------
Article No.
99-23-6

11/15/99

TRANSMISSION - FLEXPLATE
REPLACEMENT - VEHICLES WITH 7.3L DIESEL
ENGINE - SERVICE TIP

FORD:
1994-1997 F SUPER DUTY, F-250 HD, F-350
1994-1999 ECONOLINE
1999 SUPER DUTY F SERIES

ISSUE
The transmission adapter may cause a misalignment between the flexplate and torque converter causing a pre-load condition between the two components. This concern arises during a transmission flexplate replacement.
ACTION
Inspect and replace (if necessary) the flexplate reinforcement plate and crankshaft spacer when replacing the flexplate. In addition, replace the engine spacer during this procedure. Refer to the following Service Procedure for details.

SERVICE PROCEDURE

NOTE THIS PROCEDURE SHOULD BE USED FOR BROKEN/CRACKED AUTOMATIC TRANSMISSION FLEXPLATES. THIS PROCEDURE IS PARTICULARLY IMPORTANT FOR VEHICLES WHICH HAVE SHOWN REPEAT FAILURES AND/OR LOW MILEAGE FAILURES.1. Inspect the flywheel reinforcement plate for damage. The plate should be flat and free of any galling. Replace Flywheel Reinforcement Plate (F4TZ-6A366-A) if damaged.

2. Inspect the crankcase spacer for damage. The spacer should be flat and free of any galling. Replace Crankcase Spacer (F81Z-6A366-AA) if damaged.

3. Replace the Engine Spacer (F4TZ-6A369-A).

4. Install the crankshaft spacer and flexplate reinforcement plate (less flexplate) with the flexplate attachment bolts. Tighten to specification. The crankshaft spacer and reinforcement plate should be firmly secured and bolts seated. If the bolts are not seated and/or the parts are still loose, remove the bolts, spacer, and reinforcement plate and bottom tap the crankshaft holes.

5. Reinstall the crankshaft spacer, flexplate, reinforcement plate, and reinstall the flexplate attachment bolts.


PART NUMBER PART NAME

F4TZ-6A366-A Flywheel Reinforcement Plate
F81Z-6A366-AA Crankcase Spacer
F4TZ-6A369-A Engine Spacer

glenn based on the history thats my wag and I think the rebuids meay have missed the bolded items. Of course I could be wrong

 

That's quite an article Rock! Hope I can make it to AZ in Oct before I pull it. Thanks, just like Mike I can never seem to be able to rep you, later!

 

That did make for a good joke today on the phone Glenn. haha.

 

I posted the list someplace.

MAP pressure and Engine Back Pressure are 2 different sensors.

Back Pressure sensor is the tube that comes from the passenger side manifold and runs up by the Hpop.

I generally read 10-13 PSI on mine.

 

I think Glenn was asking what the parameter in the scangauge was called for the exhaust back pressure reading. Maybe you know since you're reading yours on the SG...

 

Glenn, it's call "EX. BACK PRESS" on the scan gauge. It is normally about 13-14 PSI, atmospheric. When EPPV closes on cold mornings I've seen it as high as 40 PSI under load.