Dakota 4WD V6-239 3.9L VIN X FI (1989)
Idle Speed: Testing and Inspection
1.
Remove air cleaner assembly, then plug heated air door vacuum hose.
2.
Start engine and allow cooling fan to cycle on and off at least once.
3.
Connect suitable timing light, then disconnect coolant temperature sensor and set basic timing to 12° BTDC.
4.
Stop engine and reconnect coolant temperature sensor wire.
5.
Disconnect PCV valve hose from intake manifold nipple.
6.
Attach tool No. C-5004 or equivalent (.125 inch orifice in attached hose) to intake manifold PCV nipple.
7.
Connect diagnostic readout box C-4805, then start engine and allow to idle for at least one minute.
8.
Using readout box, place read/hold switch in read position and depress ATM button until code 70 appears.
9.
Place read/hold switch to hold position, then the following should occur:
a. AIS motor will fully close.
b. Idle spark advance will become fixed.
c. Idle fuel will become enriched.
d. Engine Rpm will be displayed on diagnostic readout box in units of Rpm x 10. For example, display 95 equals 95 x 10 which indicates 950
Rpm.
10.
Check idle Rpm with tachometer. If idle speed is within 1050-1250 Rpm, then throttle body minimum air flow is satisfactory. If idle Rpm is not as
specified, replace throttle body.
11.
Shut off engine, then remove tool No. C-5004 from intake manifold PCV nipple. Install PVC valve hose.
12.
Remove readout box, then install air cleaner assembly and heated air door vacuum hose.
