Start and then start to die after 2sec

KEN LE

MEMBER
2001 LEXUS GS 300
75,000 MILES

My 2001 Lexus GS300, when starting the car up it will start and then start to die after 2sec. What does that mean? When I tried to start up the car it will start and run for about 1 or 2 sec and then it automatic turn the engine off. Once the engine is shut off, I could hear a loud humming bee noise coming from the Throttle control motor/ idle control valve. I have tried all kind of method. Like start up and press on the gas, that didn't helps either.

The car have near 75,000 miles, well maintenance up to schedule. I'm not so sure what is the reason that caused this. My best guess would be the throttle control motor is the issue. Due to the noise coming from this motor. So I end up purchasing a new motor from the dealer. But the question is there are some kinna keyway or special precaution I need to watch out before installing the new throttle control motor?

My friend is a mechanic too and he just told me there is a certain clocking or setting I need to do before installing the motor. Or else the car will Idle up and down. And that is the reason, I tried to avoid is the idle issue. The motor gear on the throttle control motor seem to move freely when you move it with your finger. And on the Motor I do not find anything that have a mark or keyway. Do I just installed and tight down the bolts? Also, what is the torque valve for this bolts?

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1 Reply

KHLOW2008

MECHANIC
41,814 POSTS

This process requires a scan tool to complete.

After removing throttle body, dissemble as follows.

1. Remove Throttle Position (TP) sensor, remove retaining screws
and TP sensor from throttle body. See Fig. 43.

2. Remove throttle control motor. Disconnect electrical connector for throttle control motor from wiring bracket. See Fig. 43. Remove retaining screws and cover to access throttle control motor. Remove retaining screws and throttle control motor from throttle body.

Reassembly

1. To install throttle control motor, ensure all gears on throttle
control motor and throttle body are clean. Apply thin coat of grease on the entire surface of the gear teeth on the throttle body. Install throttle control motor on throttle body. Ensure
holes on throttle control motor align with pins on throttle body.

2. Rotate throttle control motor clockwise and install retaining screw "A". See Fig. 45. Ensure throttle control motor is tight against the pins on throttle body. Install remaining retaining screws in throttle control motor. Tighten retaining screws to
specification.

3. Install cover and retaining screws. Ensure grommet on throttle
control motor is not pinched. Tighten cover retaining screws to
specification. Reinstall electrical connector for throttle control motor on wiring bracket.

4. To install TP sensor, ensure throttle valve opening on throttle body is about 3.5 degrees. Install TP sensor on throttle body so it is at position No. 1 (30 degrees). See Fig. 46. Rotate TP sensor counterclockwise to position No. 2 until it contacts throttle valve. See Fig. 46. Install retaining screws.

NOTE:
Ensure accelerator pedal is not depressed after turning ignition on when adjusting TP sensor.

5. To check TP sensor adjustment, reinstall electrical connector on TP sensor. Connect scan tool to Data Link Connector (DLC) No. 3 under left side of instrument panel. Turn ignition on.

6. Use scan tool to read throttle valve opening which is displayed as a percentage. Throttle valve opening may be read by accessing
THROTTLE POS under CURRENT DATA on scan tool.

7. While reading throttle valve opening, rotate TP sensor counterclockwise (toward throttle control motor on throttle body) until throttle valve opening is 14.8 percent, as this is the center of the standard throttle valve opening of 14.0-15.6 percent. Tighten TP sensor retaining screws to specification.

8. Using screwdriver, fully close throttle valve on throttle body. Use scan tool to read throttle valve opening by accessing THROTTLE POS under CURRENT DATA on scan tool. With throttle valve fully closed, throttle valve opening should be 10-14 percent.

NOTE:
When TP sensor retaining screws are tightened, this may cause the
throttle valve opening to change. Ensure throttle valve opening remains at 15.6 percent after TP sensor retaining screws are tightened. Readjust TP sensor if necessary.

9. If throttle valve opening is not within specification with
throttle valve fully closed, repeat steps 6-8 until correct throttle valve opening is obtained. Turn ignition off. Remove scan tool.

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