Idle Control Motor (Idle Stabilizer) Replacement

Overview

This procedure replaces the idle control motor (also called the idle stabilizer) on your Porsche 944 S2 with its 3.0L engine. The idle control motor helps maintain a steady idle speed when the engine is cold or under extra load, like when the air conditioning is on. It’s controlled by the engine computer and lets small amounts of air into the intake manifold to adjust the idle. If it fails, you might notice a rough idle, stalling, or even a sucking sound from an air leak. This guide walks you through the replacement process step-by-step, assuming you’ve got some mechanical know-how.

Tools Required

• Standard mechanics tool set
• 13mm wrench
• Flathead screwdriver (for hose clamps)

Parts Required

• Idle control motor (944 606 113 00)
• Rubber mounts (2) (944 110 197 01)

Required Additional Procedures

Steps in these procedures are required to complete this process:

• Fuel Injector Removal
• Intake Manifold Removal
• Allen Head and Cheese Head Removal
• Idle Speed Adjustment

Step-by-Step Procedure

Step 1: Remove the Intake Manifold

1. Start by removing the intake manifold to access the idle control motor. Follow this link to ensure this step – Intake Manifold Removal – of the process is followed accurately.

Step 2: Loosen the Idle Control Motor Bracket

2. With the intake manifold off, find the idle control motor mounted near the throttle body. Use a 13mm wrench to loosen the bolt clamping the idle control motor to its bracket. Don’t remove it fully yet—just get it loose.

Step 3: Disconnect the Left Side Hose

3. Locate the hose connecting the idle control motor to the intake boot (this is the left side hose). Use a flathead screwdriver to loosen the hose clamp, then carefully pull the hose off the motor.

Step 4: Unplug the Electrical Connector

4. Find the electrical connector plugged into the back of the idle control motor. Gently press the release tab and pull it off to disconnect it.

Step 5: Remove the Idle Control Motor

5. Slide the idle control motor out of its bracket. The other hose (right side) will still be attached at this point. If the rubber mounts are broken, the bracket might come out with the motor—don’t worry, you’ll handle that next.

Step 6: Replace Broken Rubber Mounts (If Needed)

6. If the rubber mounts are broken, remove the bottom pieces of the old mounts from the engine block. You might need to use a wrench or pliers if they’re stuck.
7. Install new rubber mounts (944 110 197 01) onto the block and secure them with their nuts. Tighten to 20 Nm (15 ft-lbs).
8. Take the old mount pieces off the bracket and set the bracket onto the new mounts.

Step 7: Prepare the New Idle Control Motor

9. Take the hose still attached to the old motor and mark it with a piece of tape or a marker so you know how it was oriented. Then, remove it from the old motor and attach it to the new idle control motor (944 606 113 00) in the same direction. Check the arrow on the motor to make sure the flow direction is correct—don’t install it backward!

Step 8: Install the New Idle Control Motor

10. Slide the new idle control motor into the bracket while attaching the left side hose back onto it. Tighten both hose clamps with a flathead screwdriver.
11. Tighten the bracket bolt with your 13mm wrench to 20 Nm (15 ft-lbs).

Step 9: Reconnect the Electrical Connector

12. Plug the electrical connector back into the new idle control motor until it clicks into place.

Step 10: Reassemble the Engine

13. Reinstall the intake manifold. Follow this link to ensure this step – Intake Manifold Removal – of the process is followed accurately in reverse order.
14. Reinstall the fuel rail and injectors. Follow this link to ensure this step – Fuel Injector Removal – of the process is followed accurately in reverse order.

Step 11: Test the Repair

15. Connect the battery, start the engine, and let it idle. Watch for any leaks around the hoses or intake manifold.
16. Check that the idle speed stays steady, even when cold. For the Porsche 944 S2, it should be 900 +/- 50 rpm. If it’s off, adjust it. Follow this link to ensure this step – Idle Speed Adjustment – of the process is followed accurately.

Post Procedure Checklist

• Check for air leaks around the idle control motor hoses and intake manifold.
• Confirm the idle speed is steady at 900 +/- 50 rpm, even when cold.
• Ensure the electrical connector is secure and not loose.
• Verify no tools or parts are left in the engine bay.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manual, Volume 1
• Youtube