R 3500 P/U 2WD V8-350 5.7L (1989)
Figure 1 Terminal Arrangement In Connector
5.
With IAC valve connected, ground the diagnostic terminal (ALDL).
6.
Turn ON ignition, DO NOT START engine. Wait at least 10 seconds (this will allow the IAC pintle to extend and seat in the throttle body.).
7.
With ignition ON, engine stopped, test terminal still grounded, disconnect IAC valve electrical connector. (This disables the IAC valve in the
seated position). Remove the ground from the diagnostic terminal.
8.
Connect a SCAN tool to the ALDL connector and place in open mode. If a tool is not available connect a tachometer to the engine.
9.
START engine. With transmission in NEUTRAL, allow engine rpm to stabilize.
10.
Check rpm against specifications. Disregard IAC counts on SCAN tool with the IAC disconnected. If the engine has less than 500 miles or is
checked at altitudes above 1500 feet, the idle rpm with a seated IAC valve should be lower than values in chart.
11.
If the minimum idle air rate is within specifications, no further check is required.
12.
If the minimum idle air rate is not within specifications, perform the following procedures:
Stop Screw Plug Removal
13.
If present, remove the stop screw plug by piercing it with an awl, then applying leverage. The screw is covered to discourage unauthorized
adjustments.
14.
With the engine at normal operating temperature 185-212 degrees Fahrenheit (85-100 degrees Celsius), adjust stop screw to obtain nominal rpm
per specifications with seated IAC valve.
15.
Turn ignition OFF and reconnect IAC valve electrical connector.
16.
Disconnect the SCAN tool or tachometer.
