kick down/throttle valve cable

[kshifttiger]

ive got 87 auto that doesnt shift down when im at wot, i can stomp the pedal and it follows the shift schedule completey and never shifts down unless im coasting or at a stop. ive been looking in class for a while now and i keep seeing something a bout a kickdown switch but can't find any thing on it except that it is in the car somewhere. can anyone help me out here?

 

[modmonster2008]

throttle position sensor perhaps? IIRC they contribute to shifting problems as well, someone chime in on this one?

 

[mkiiichip]

there should be a cable that runs from the throttle linkage to the transmission (not the throttle cable or cruse control, the other one) is it connected, to pull out, as the throttle is opened?

next you should notice there is a little crimp (on the cable itself) that peeks out of a rubber boot at WOT.

its kinda hard to explain, a pic of all the throttle linkage would help.

 

[IJ.]

"Line Pressure Cable"

it has nothing to do with kickdown.

 

[kshifttiger]

the line pressure cable is connected, no slack to mess things up, im not sure what the crimp on the cable is that your talking about though chip but i'll take a look after class.
so jj, if thats got nothing to do with kickdown, what does?

 

[89nasupra]

LIke IJ said, it's a line pressure cable. I melted mine to my exhaust manifold a few weeks back and as long as I baby it, it is fine. Now, my TPS in on the fritz and it was shifting from first to second then third instantly but would down shift if i put my foot in it. I messed around with the tps cause i have a code 51 that i beleive is linked to it not bring in specs anymore and it's not. now after i messed with it it will not shift till it goes over 2000 RPM and it won't down shift anymore. Here post 17 by hvyman. it's a link to test your TPS. http://www.supramania.com/forums/showthread.php?109080-n-a-to-turbo-swap-trouble./page2

good luck and hope this helps

 

[jdub]

the line pressure cable is connected, no slack to mess things up, im not sure what the crimp on the cable is that your talking about though chip but i'll take a look after class.
so jj, if thats got nothing to do with kickdown, what does?

It's IJ

The tranny computer controls shifts - pull the diagnostic codes:
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?Section=AT&P=13

There's also a troubleshooting section for the tranny in the same TSRM section above - might want to read it.

I would also pull the main ECU codes:
http://www.cygnusx1.net/supra/TechTips/engine_error_codes.aspx

 

[IJ.]

the line pressure cable is connected, no slack to mess things up, im not sure what the crimp on the cable is that your talking about though chip but i'll take a look after class.
so jj, if thats got nothing to do with kickdown, what does?

Usually a badly adjusted or faulty TPS.

Run through the links JDub provided it's all in there.

You can actually pulls Trans codes and it may give you a hint where to look.

 

[89nasupra]

Usually a badly adjusted or faulty TPS.

Run through the links JDub provided it's all in there.

You can actually pulls Trans codes and it may give you a hint where to look.

Would it be possible that the circuit that tells it to kick down is bad but not the circuit that tells the ECU throttle position?

 

[IJ.]

It's one in the same.

 

[kshifttiger]

opps, sorry IJ, im priting out the codes to take back with me later, i think 89 might be on to something with the tps, i never thought to check it among the rest of the electrical, in any case if mine is bad, ill just swap the spare over today and test that out. this is the first auto ive ever owned so this shift timing is new to me. looking at tsrm it just seems like its folllowing vehicle speed only.

 

[IJ.]

89 was asking if there's seperate circuits, there isn't the ECT looks at TPS and Speed and makes it's decision to kickdown or not based on a table.

 

[kshifttiger]

code 41 throttle position angle, the vta pin was practically falling out of the connector, never had a drive issue other than shifting with that, amazing. for the moment i did all i can to hold it in place till i come across another connector to swap min out with. hope this works

 

[kshifttiger]

yup that was it, problem solved. what a day and night difference!
also swapping the tps, made things worse so for anyone else that sees this, the newer tps doesnt work on the older style engines. it kept hitting the fuel cut for some reason.
thanks to all for the info