Any way to tune my automatic to not lock up at 30 mph? If I remember my last Formula automatic, it would wait until 35 to 40 mph.
I have already tried to adjust the throttle valve cable going to the tranny, and made no difference other than sore fingers from resetting it. I was only able to get about 3 to 4 clicks from the cable with the throttle fully open. Yes, I moved the throttle at the engine on the throttle body, and not with the gas pedal as I have read that is not the best thing to do.
What's the reason to do that? The ECM decides when to lock it, so I guess the only real option is to reprogram it. My '85 duke also locks at about 30mph when I feather the gas pedal. Don't know if there are differences in years/engines when the ECM locks up the converter.
EDIT: The ECM reads the speed from the VSS. Did you by any chance have bigger wheels/tires on your previous Fiero? Was the speedo reading low? That may be a reason why it was locking later.
[This message has been edited by cebix (edited 08-17-2016).]
What's the reason to do that? The ECM decides when to lock it, so I guess the only real option is to reprogram it. My '85 duke also locks at about 30mph when I feather the gas pedal. Don't know if there are differences in years/engines when the ECM locks up the converter.
EDIT: The ECM reads the speed from the VSS. Did you by any chance have bigger wheels/tires on your previous Fiero? Was the speedo reading low? That may be a reason why it was locking later.
Mostly it seems the engine is bogged down at 30 mph and only running at around 1100 rpm.
This transmission was re-geared more for highway cruising than off the line type driving. Wheels and tires are identical to what I had on the Formula.
I did not think the ECM "talked" to the transmission from a lot of the posts I have read? Not really sure, but thanks for the input cebix!
First scan ECM when driving and make sure ECM and speedo match. If not, speedo needle maybe off or early sign of iffy parts on the board. VSS goes to speedo board and divide by 2 for ECM use.
Yup, TCC lock-up is ECM/PCM controlled item via PROM/Flash programming. You can't adjust it w/o reprogramming.
You could try adding a delay (sold by many trans shops and parts dealers) but depend exact reason why, may not help.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Thanks everyone. I guess I will have to send my modified chip that I had specially programmed back to phonedawgz to have him reprogram it again. Heck, he just sent it out yesterday, so it will be going back to Green Bay soon.
Speedo is quite accurate as I go through a construction zone on my way to work, and they have a radar set up to warn people of how fast they are going. Tested it with all 3 of my cars, and when my speedo says 45, I am going 45 on all 3.
I did a fair amount of research when our TCC went out on Kevin's car. The Torque Converter Control solenoid is driven by the ECM to shift transmission fluid to the lockup mechanism in the torque converter. When the load on the engine/trans is light it will lock up the torque converter around 30 MPH (or higher if you were using a lot of power). However, if you put any load whatsoever on the engine, it will immediately unlock the converter and the engine will rev up a bit as necessary to give you more oomph. Driving on a sleepy little road I can feel it as I start to go uphill and see it in the RPMs. If you step on the gas, it will disconnect and down shift so quickly you probably won't be able to feel it.
I can't imagine why you would want it to lock up at a higher speed since it will not lock up if the engine is being stressed. You could always tie into the solenoid electrical signal with a light to give you an idea when that solenoid is active. I think you will be surprised at when it turns off and on.
30 mph TC lock is close to shift points on many cars and can be a pain to drive in city. You get no real benefit locking the TC for city driving because trans is shifting a lot for stop signs etc. Is why many don't lock at all until until trans in high gear, 35-40mph and low engine load.
TH125 has 3rd gear switch in the circuit. 4T60 (non E) has 3rd and 4th gear switch inputs to ECM to lock because you can drive w/o overdrive active. Depending trans setup, Overdrive can be a big pain to drive in the city too. Even 5 speed stick can has problems use 5th gear in the city. I had 3 and 4 speed sticks and often didn't high gear in the city.
Delay sold by many shops stops many ECM to lock/unlock too quick for change in engine load. Many older GM and other ECM are program to unlock when you push the gas even a little bit and is very annoying to many owners.
Good point, Ogre! My driving is all either highway or the 7 miles to work at 45 MPH with only 3 traffic lights and two stop signs. I just don't feel the shifting much except for right after that second stop sign. It is slightly up hill and I can always feel/hear when the TCC kicks in.
