Carrera 3.2 Idle Position Switch Replacement

[tx63conv]

I believe I need to remove the throttle body to access the two small phillips screws that hold the idle position micro switch for replacement. Are there any write ups or pics that walk through this process?

[wazzz]

You've done part of it already. Next, disconnect accelerator rod from throttle body by removing the tiny circlip (tab can be seen in lower left of your red circle). Make sure you don't drop it.
Throttle body is held to intake by four pan head bolts, one of them is visible near center of red circle.
Disconnect black connector on right.
When lifting throttle, you'll find an O ring. Make sure it does not fall behind.
Disconnect cruise control.

[tx63conv]

wazz--thats what I needed. Thanks for the heads up on the o ring.

Follow up items:
(1) I have the 90 degree rubber boot from the air plenum to the throttle body pushed to the side, there is a hose attached to the back that is preventing me from full removal--should I leave or fully remove?
(2) how do I get the wire throttle cable out of the throttle lever--do I need to? or should I leave and set throttle body to the side?
(3) When you say 'disconnect cruise control' I assume you are referring to #2 above or am I missing something?

[nene]

I removed the entire throttle body as it made it easier to attach the switch.

[wjdunham]

Can one purchase a replacement switch? I am seeing NLA from our host and not having much luck finding another source. Looks like the switch is permanently riveted to the metal arm that screws on to the throttle body.

[tx63conv]

wjdunham--I just ordered one and received last week. 911-606-013-03-OEM. The actual switch is riveted to a metal plate that attaches to the manifold with two phillips head screws.

The metal arm/drag arm (left side of throttle body in pic above) contacts the switch.

Consensus is to remove the throttle body to get access to the screws that mount the switch.

[wjdunham]

Yikes, $200 for that switch!

[tx63conv]

Originally Posted by wjdunham

Yikes, $200 for that switch!

YUP...crazy. I have cleaned mine thoroughly with spray carb cleaner and adjusted the throttle arm and it is back working. I am probably going to run as is with the new one as a backup.

I adjusted the arm as it felt like it was slamming down on the switch--which it is not supposed to. I have it set now to the tiniest of movement of the throttle arm and I hear the click of the micro switch.

[proporsche]

here you have it

[wazzz]

Here is a couple of pics of what you should end up with (hopefully yours will be in better shape)

[wjdunham]

My problem is that I can hear the switch clicking, but the resistance seems to be a bit inconsistent when closed, some times as high as 50 Ohms, but mostly in the 4-5 Ohm range. I cleaned the external contact pins but still not getting what looks like a solid contact. The switch is sealed so doesn't look to be any way to clean the internals.

[wazzz]

Maybe you can tap it and click it repeatedly to help clean the contacts.

I just checked the Motronic internal schematic and I think even a bad contact like 50 ohms should be correctly interpreted as a closed contact to ground. All resistors involved in the input channel for this signal are in the 15-100k range.

[wjdunham]

Originally Posted by wazzz

Maybe you can tap it and click it repeatedly to help clean the contacts.

I just checked the Motronic internal schematic and I think even a bad contact like 50 ohms should be correctly interpreted as a closed contact to ground. All resistors involved in the input channel for this signal are in the 15-100k range.

Thanks, I was wondering if that might be the case, that the switch impedance only needs to be below some reasonable threshold and not a complete short to ground.

Bill