No kick down at full throttle

[dragon850]

As always there is something else to fix on the 8
I have noticed this before even with the SC connected. Transmission will up shift and down shift normally and smoothly however, when I floor it kickdown is not activated and the car keeps accelerating in high gear. Also it does seem to upshift rather quickly compared to other 8s Ihave driven... I realize that there is no physical kick down switch on our cars and kick down is activated via EML to TCU signal.
I have unknown EML chip (possibly stock) and Dinan transmission chip. Where should I start ?

[Timm]

Even though the throttle pedal does not have a kick-down switch, the EML produces a 'kick-down' signal (Pin 2, X8500) dependant on the pedal position. I do remember that there was some discussion last year regarding this as some pedal units can produce a wider range of values than others.

[dragon850]

What do you think I should do, replace throttle position sensor, replace eml chip, replace TCU chip? Replace all of the above?
Just drove the car, basically everything works as it should including S3 mode but in D there is no kick down...

[Timm]

If you can diagnostics get running you can check the action of the pseudo kick down and work out where the problem is. There is a member here that knows more - I'll try and remember who by doing a little searching......


......here we go:

http://www.bimmerforums.com/forum/me...Omega-man-1969

[Omega man 1969]

I may be able to help . Take a read from page 8 on http://www.bimmerforums.com/forum/sh...g-850CSi/page8

The EML looks at the angle of the throttle pedal and triggers kckdown once past a certain angle. It maybe the throttle stop screw not allowing the pedal to be pressed down far enough....its easy to adjust.

Ideally you would need to look at pedal angle using diagnostics.

[dragon850]

I may be able to help . Take a read from page 8 on http://www.bimmerforums.com/forum/sh...g-850CSi/page8

The EML looks at the angle of the throttle pedal and triggers kckdown once past a certain angle. It maybe the throttle stop screw not allowing the pedal to be pressed down far enough....its easy to adjust.

Ideally you would need to look at pedal angle using diagnostics.

Thank you, I do have DIS to test throttle position angle, sent you a PM.

[dragon850]

Resurrecting this thread. I achieve 81 degrees gas pedal angle on the DIS. However my kick down is speed and RPM dependent, if I am cruising at 50 mph in 3rd gear and punch it I do not get kicked down into 2nd, just keep accelerating in 3rd.
On the freeway speeds around 75 mph kick down works but I really have to press the pedal down hard for it to drop down to 3rd and rip into 4th.
Does EML interpret not only the angle but the voltage too? I can never get 3.8V..
Did play with height adjuster, even removed it.
Will change pedal bushings just in case.

[liquidblueloft]

it almost sounds like the potentiometer isn't sending the proper signal to the eml???? But that would throw a code

[BMSman]

My Car is also very reluctant to downshift and upshifts much sooner than I would expect. I completely stripped and rebuilt the valve body as a precautionary exercise and it shifts very smoothly.

In Sport mode it shifts about where I would expect it to shift in Economy but of course I loose 4th gear. Car has the stock transmission chip but I have purchased a Dinan chip to try.

[Dynamic Entry]

Resurrecting this thread. I achieve 81 degrees gas pedal angle on the DIS. However my kick down is speed and RPM dependent, if I am cruising at 50 mph in 3rd gear and punch it I do not get kicked down into 2nd, just keep accelerating in 3rd.
On the freeway speeds around 75 mph kick down works but I really have to press the pedal down hard for it to drop down to 3rd and rip into 4th.
Does EML interpret not only the angle but the voltage too? I can never get 3.8V..
Did play with height adjuster, even removed it.
Will change pedal bushings just in case.

Curious if/how you resolved this issue.


In this thread, Shogun mentions the spec voltage for automatic cars is supposed to reach 3.7-3.8 vdc


And here is the page from section 12 of the 1990 repair manual that shows the test/adjustment procedure, confirming those voltages

12-72.3.JPG


Dragon850, you mention adjusting/removing the 'height adjuster' which I presume is the 'knurled head' pedal stop on the floor underneath the accel pedal?

Did doing so allow you to feel any resistance at the end of the pedal travel?

The repair manual mentions the "kickdown pressure point" and I have heard people mention the last ~10% of the switch travel requires greater pressure
check adjust accel pot.JPG


My car is only putting out 3.39v with pedal to the floor, is reluctant to kick-down outside of Sport mode, and I can't activate the stomp test (I expect it's related?)

PXL_20210919_061148925_3.jpg