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Trans kickdown relay debugging

 
Old 02-23-2011, 01:18 AM
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Speedtoys
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Default Trans kickdown relay debugging

88 S4, Auto

I dont seem to have a functioning kickdown setup...

The tranny shifts fine, but at WOT it'll shift a tad early..not too hard or anything, but just doesnt seem to have that signal from FULL wot to shift at really high RPMs rather than the normal not quite WOT, that exists before you hit the relay switch.


What components do I start debuggin or testing?
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Old 02-23-2011, 01:45 AM
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Old 02-23-2011, 01:50 AM
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Awesome..will be all over those things.
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Old 02-23-2011, 02:38 AM
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if you want it to shift a touch higher in the rpm try increasing the tension of the bowden cable.... My stock 88 that was running well would shift every gear at 6000-6200.... I would cruise around the track in 3....then use kickdown to power out of corners...it was fun!!! At least it sounded great!!!
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Old 02-24-2011, 02:33 PM
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Ok..the bowden is tight to the tranny, maybe a little too tight, the trans reacts on throttle quicker.


However..no kickdown relay action.

I can HEAR it click under the pedal, I can feel it click..but theres no action with it.


I guess, crawl under there see if its plugged in??
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Old 02-24-2011, 04:13 PM
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borland
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Test the kickdown solenoid for proper operation with the throttle kickdown switch, but without the engine running. From post #10.....

"Open the passengers side door, with the ignition key on push the gas pedal to the floor you should here a click by the door."

https://rennlist.com/forums/928-foru...wn-switch.html
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Old 02-24-2011, 04:41 PM
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Is the gas pedal contacting the kickdown switch? This happened to mine and I had to adjust the ball & cup socket behind the pedal.
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Old 02-24-2011, 05:39 PM
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Here's what the electric solenoid valve looks like, center / low on rear of trans near x-member
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Old 02-24-2011, 05:49 PM
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Originally Posted by borland View Post
Test the kickdown solenoid for proper operation with the throttle kickdown switch, but without the engine running. From post #10.....

"Open the passengers side door, with the ignition key on push the gas pedal to the floor you should here a click by the door."

https://rennlist.com/forums/928-foru...wn-switch.html

First think I'll do after work, is this.

Where is this relay that I'll be listening for, located?
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Old 02-24-2011, 06:31 PM
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SteveG
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On the CE panel, relay XV is bottom row, seventh from left.
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Old 02-24-2011, 06:59 PM
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I had a similar problem. The side panel (console) screw was loose down by gas pedal, which would push the pedal away from kickdown switch when I would apply pressure. Tightened the screw and all was fine.
Thomas
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Old 02-24-2011, 07:43 PM
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there are two parts to the circuit....the switch itself under the gas pedal can fail & the solenoid that plugs into the trans can also fail....typically its the switch under the pedal.....

One of my favorite things to do in sharky was to cruise along at 60mph......rpms at a lowly 2200.....then drop the hammer....a quick DOUBLE downshift...BWAAAHHHHH and your GONE..... :>)

I knew I had a strong 928 when I did this during the test drive with Susan from Devek....her response was "wow, this one is strong!"....many years later I figured out its 279whp...she was right
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Old 02-24-2011, 07:57 PM
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Ice:

Well, I'll go on the rollers at Thill next weekend with A/F, to see where my efforts have gotten me so far.
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Old 02-24-2011, 10:56 PM
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Default Mine was not

Originally Posted by Mongo View Post
Is the gas pedal contacting the kickdown switch? This happened to mine and I had to adjust the ball & cup socket behind the pedal.
Mine was a problem too. Tab on the pedal wasn't contacting without putting waaayyy too much force on the WOT position.

Then I intalled a manual bypass, and although adusted, I don't care anymore......
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Old 02-25-2011, 01:51 AM
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Originally Posted by SteveG View Post
On the CE panel, relay XV is bottom row, seventh from left.

Ok.


Switch under pedal is getting depressed.

Switch works..tested with meter.

No voltage between the two plug leads..Id assume there is SOME voltage there being crossed coming from the harness, right? (with key on of course)

And the kickdown relay..no noise or anything from it, no life at all when the kickdown button is depressed. PUlled it, contacts were clean, are cleaner now..but relay has zero action.

What fuse might I look at?
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