Advice on setting base idle

[norville]

Hello, I'm trying to set base idle. I've followed this procedure from Dweb:

With the engine at operating temperature and an accurate tachometer connected:

Center punch and drill (1/8" bit) the tamper proof plug located on the throttle housing.

Remove the plug with a sheetmetal screw and pliers.

Discard the plug and clean up any metal chips.

Switch the ignition on - DO NOT START THE VEHICLE.

Disconnect the stepper motor plug

Switch ignition off

Listen for click from EFI main relay (under the right front seat).

Reconnect the stepper motor plug.

Switch the ignition on - DO NOT START THE VEHICLE.

Disconnect the stepper motor plug.

Start the vehicle in neutral without touching the accelerator

Adjust the base idle speed with a 3/16" Hex wrench to 550 to 650 RPM by turning the base idle screw. Turning counter clockwise will raise the speed and vice versa.

Reconnect stepper motor plug.

Switch ignition off.

WAIT for main relay click

Switch ignition on, start the engine and rev briefly to 2000 RPM

Idle speed should stabilize at 665-735 RPM

The issue is I cannot get the idle lower than about 900 rpm. Am I supposed to block off or pinch the bypass hose also? I've tried many times and still cannet a low idle The screw is bottomed out. Timing is set at 8degbtdc.

A vac guage only shows 16"Hg Could I have a vacuum leak?

thanks
bob

[Muddy Oval]

I'd say you have a vac leak. You shouldn't ever have to change the base idle- that's why there's a 'tamper proof plug' on it.

[LRR219]

Originally Posted by Muddy Oval

I'd say you have a vac leak. You shouldn't ever have to change the base idle- that's why there's a 'tamper proof plug' on it.

If you werent every supposed to chage it... it wouldnt be adjustable....

[Elemental]

I have never seen one rover set with base adle correct from the factory.

I dont see blocking off the bypass hose in your proceedure.

Try this.....

1. Turn off all electrical accessories.
2. Connect an accurate tachometer (do not use vehicle tachometer).
3. Clamp idle speed control air bypass hose.
4. Observe idle speed; it must be 525 +/- 25 rpm.
5. If idle speed is not correct, remove tamper-proof plug from idle speed bypass screw.
6. Adjust idle speed until correct.
7. Remove clamp from bypass hose.
8. Replace tamper proof plug.
9. If MIL code 48 sets, reset code.

[norville]

Originally Posted by Elemental

I have never seen one rover set with base adle correct from the factory.

I dont see blocking off the bypass hose in your proceedure.

Try this.....

1. Turn off all electrical accessories.
2. Connect an accurate tachometer (do not use vehicle tachometer).
3. Clamp idle speed control air bypass hose.
4. Observe idle speed; it must be 525 +/- 25 rpm.
5. If idle speed is not correct, remove tamper-proof plug from idle speed bypass screw.
6. Adjust idle speed until correct.
7. Remove clamp from bypass hose.
8. Replace tamper proof plug.
9. If MIL code 48 sets, reset code.

Thanks

that's what I was looking for

bob

[daway]

what is the correct idle speed for a 93 rrc? mine is about 750rpm and i always thought that is the correect idle. alot of my other cars alway been around 750rpm.

[Elemental]

Dont rely on your tach on your dash. It is horribley inaccurate.

750 is about right under computer control.... When running on jsut base idle (Prceedure above) it's about 525