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Upshift 928 S4

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Old 02-05-2005, 09:04 AM
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Eurosportmotorcars
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Default Upshift 928 S4

Hello,
I got a 1988 S4 recently. The car runs fine,other than the upshift points.
Even with maual setting to first gear, the trans shifts to second at 4300 rpms.
Any Ideas?

Thanks
Old 02-05-2005, 10:34 AM
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adam928
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Hmm... Im not sure about when at the RPM range it should upshift.. but my guess is a stucked or shortened kickdown switch.

Does this occur at all gears?
Old 02-05-2005, 10:51 AM
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Schocki
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If you want to quickly check your kickdown relais, here is how it's done.
Sit in the car turn ignition on (engine NOT running), open door and push down the accelerator pedal all the way down. As soon as you engage the kickdown switch you should hear a click from the tranny (kickdown relais). Remember you have to push down really hard! As soon as you hear the klick from the back and you ease off just a little the relais should disengage again.
If that does not work the relais could be permanently On or OFF.
Old 02-05-2005, 11:38 AM
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>I got a 1988 S4 recently. The car runs fine,other than the upshift points.
>Even with maual setting to first gear, the trans shifts to second at 4300 rpms.
>Any Ideas?

Try adjusting your "kickdown" cable (on 87-up it runs from Intake side console to tranny). There is an adjuster on the Cable end at the Intake Side Console. Tighten it a little at a time until it changes into second at around 5500 (preferred)-6000(at the most) rpms.

Caution: do not over tighten as you could break the plastic cable clip inside the tranny, MAJOR pain in the...... The best way to get a feel for it is too use your hand and hold the throttle wide open (at the Instake side console) and then pull gently but firmly on the exposed section of the "kickdown" cable until you feel it stop, you should have at least approx. 1/2" of play for safest results.
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Old 02-05-2005, 11:42 AM
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WER
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Mine does the same thing, kicks down fine in all gears, but shifts from 1-2 at 4500, holds to 6000 in the rest, so the kickdown switch and relay are fine, I think. I hope someone will come up with a solution....
Old 02-05-2005, 12:04 PM
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>Mine does the same thing, kicks down fine in all gears, but shifts from 1-2 at 4500, holds to 6000 in >the rest, so the kickdown switch and relay are fine, I think. I hope someone will come up with a >solution....

If you notice, the rpms at this gear change (1st-2nd from dead start in "2") will be at the same or very close no matter if you have it to the floor or part throttle, hence the reason the Kick down relay has nothing to do with this behavior. (concerning the 1st-2nd from dead start in "2" change only)

Adjust your "kickdown" (control pressure) cable.

Oh, and while you at it, adjust your Throttle cable also, they are notorious for getting slack and not opening the throttle plate 100%. Same procedure as "Kickdown" cable, hold Console WIDE OPEN, then grab exposed part of cable that goes from console around back of intake to the throttle body, if you have slack, you are missing some power! Adjust accordingly, BUT without any "real" slack.
Old 02-05-2005, 12:45 PM
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Bill,
Just noticed you have an 84, adjustment procedure is a little different on 16v cars.

Have someone hold your acceleator pedal all the way to the floor (meaning ALL the way engaging kickdown switch) then reach thru the intake to throttle body and see if you can move it farther, if so you need to adjust the accel. cable at the firewall until throttle plate is wide open (no slack) when someone is holding pedal all the way down..
Old 02-05-2005, 01:07 PM
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Thanks, David, I'll give it a try and let you know..
Old 02-05-2005, 02:40 PM
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Hello,
thanks for oll the quick replys. All Cables are adjusted to the book. I can shorten the shifter cable but it will only move all other shiftpoints up a little, does not effect the 1st to 2nd upshift.
The kickdown switch is working in other gears but not as I am use to it from my Benz. It only makes it shift if from low rpms.
Shouldn't the shifter in 2nd overide all other inputs and run it up to max rpms?
If I put my Benz manuel in 2nd, it runs up 1st and 2nd to the red line.
Any more Ideas on that?

Thanks
Old 02-05-2005, 03:21 PM
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If all other adjustments/checks only move shift points up on all the gear changes except 1>2 then I suspect you have something internal going on. For internal issues I always defer to the Slush Box experts...
Old 02-05-2005, 04:16 PM
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The upper shift points are electronically limited (5900 +-60 rpm) by interruption of the electrical power to the kickdown solenoid valve. Since your other shifts appear to be electrically limited, the likely area of trouble is the transmission's valve body.

There is an adjustment screw on the valve body that delays full throttle shifts. That only requires dropping the transmission pan. For the adjustment procedure, refer to WSM Volume 3, page 38-124.
Old 02-05-2005, 06:40 PM
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Euro
My 88S4 auto routinely pulls redline (6200) shifts from every gear?
Old 02-05-2005, 07:06 PM
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Don't know? I got that rpm spec from the Porsche A28 Automatic Brochure located on the Morehouse CD. The fuel injection brain does the work. Maybe your chip set is modified.
Old 03-05-2005, 11:29 AM
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Default Upshifts

Originally Posted by borland
The upper shift points are electronically limited (5900 +-60 rpm) by interruption of the electrical power to the kickdown solenoid valve. Since your other shifts appear to be electrically limited, the likely area of trouble is the transmission's valve body.

There is an adjustment screw on the valve body that delays full throttle shifts. That only requires dropping the transmission pan. For the adjustment procedure, refer to WSM Volume 3, page 38-124.
Thanks for the tip, does anybody have such pages as word or Adobe file to send as attachment?
Thanks



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