Astro Van M L4-151 2.5L (1985)
C.
Reduce cold idle speed to 1600 rpm.
1.
Remove dash extension.
2.
Remove engine cover.
3.
Install tachometer. The tachometer (tach) terminal is next to the engine control switch (bat) connector on the distributor cap (Reference
Figure 3).
Note:
The tachometer terminal must never be allowed to touch ground because damage to the module inside the distributor and/or ignition coil
can result.
4.
Reduce cold idle speed to 1600 rpm by adjusting the fast idle screw. Refer to tune up label for procedure.
5.
Remove tachometer and reinstall engine cover and dash extension.
6.
On a clean dry surface, next to the existing tune up label located on the fan shroud, place label P/N 10066488.
FIGURE 4 - PROM 4.3L 1986 M VAN
1986 Model 4.3L TBI Engines
C.
Replacement of the PROM, Figure 4.
1986 model vehicles built before VINS listed below require PROM replacement.
VIN
EMISSIONS
GB203188
Federal Emissions
GB203623
California Emissions
Vehicles built after these VIN breakpoints have PROM factory installed.
Note:
Any time the PROM is installed backwards and the ignition switch turned on, the PROM is destroyed and must be replaced.
1.
Disconnect negative battery cable.
2.
Remove kick panel from right side of the vehicle (1 screw) interior.
3.
Remove ECM (2 screws).
4.
Disconnect electrical harnesses from ECM module.
5.
Remove ECM cover (2 screws).
6.
Remove PROM from ECM and replace with new PROM, P/N 16068877 (Federal), P/N 16068926 (California).
7.
Replace ECM cover.
8.
Reconnect electrical harness.
9.
Secure ECM module to its mounting location.
10.
Replace kick panel.
1985 - 1986 2.5L TBI Engines
C.
Vehicles equipped with this engine do not require PROM replacements.
D.
Brake Burnish Procedure
On a dry clean level roadway, make twelve stops using the following procedure:
