1992 Isuzu Rodeo Question High Idle

Hi there,

Thank you for the donation,

The idle speed is controlled by the ECU and a idle control motor, I would start with cleaning the idle motor ports and checking for vacuum leaks as this will also hold a high idle speed, start here.

Mark (mhpautos)

I would be thinking that the idle control motor is faulty, did you do the scan and check for any unresolved fault codes?

Mark (mhpautos)

I would replace the ICM.

Mark

Does it have cruise control? If yes remove the cable for cruise control at the throttle, if that works OK, if not remove throttle cable, one of them may be holding the throttle open a bit.

It doesn't make a difference about checking the throttle cable for binding.

Not yet! Remove at the throttle body, and if the idle drops to normal, operate it by hand and rev it then let it go, if it returns to a normal idle, replace the cable. See if the throttle plate closes fully.

Has the timing been checked/set to 10 BTDC at below 1000 RPM? There is a tech bulletin on this...
Reference Number(s): SB93-02-002
Related Ref Number(s): SB93-02-002
ARTICLE BEGINNING
RODEO (UC) AND PICKUP (TF) 3.1L V6 IDLE SPEED/IGNITION
TIMING SPECIFICATIONS (WORKSHOP MANUAL CORRECTION)
Model(s): 1991-92 Isuzu Rodeo, 1991-92 Isuzu Pickup
Group: Fuel
Bulletin No.: SB93-02-002
Date: December, 1993
AFFECTED VEHICLES
1991-92 Rodeo (UC) and Pickup (TF) models equipped with 3.1L V6 engine.
SERVICE INFORMATION
Idle speed and ignition timing specifications for affected vehicles are incorrectly described in the
following Workshop Manuals:
This Service Bulletin contains the correct idle speed & ignition timing specifications for the
referenced workshop Manual pages as well as revised Vehicle Emission Control Information label
illustration.
The correct vehicle specifications for the 3.1L V-6 engine are:
No adjustment to "Â idle speed is required.
"Â Ignition timing is 10 BTDC under 1000 rpm.
IDLE SPEED/TIMING - WORKSHOP MANUAL CORRECTION -1992 Isuzu Rodeo S Page 1 of 2
http://www.

Checked for vacuum leaks? You may have a vacuum leak, get a can of spray Throttle body cleaner, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs! Keep spray off the exhaust manifolds and pipes! Fire hazard!