Pickup 2WD L4-155 2555cc 2.6L SOHC VIN E 2-bbl (1988)
Altitude Compensator: Testing and Inspection
Federal Vehicles
Testing at Elevations Below 1,200 M (3,900 FT.)
Fig. 152 Testing vacuum regulator valve system
1.
Warm up the engine until coolant temperature exceeds 85 degrees C or 185 degrees F.
2.
Connect a timing light to the engine and remove the air cleaner.
3.
Disconnect the vacuum hoses (black, red striped, and black) from the carburetor primary emulsion well bleed nipple, secondary emulsion well
bleed nipple, and jet air nipple and plug the nipples, Fig. 152.
4.
Connect a hand vacuum pump to the vacuum hoses, one hose at a time, and verify that vacuum holds.
5.
Reconnect the disconnected vacuum hoses to their original positions.
6.
Run the engine at idle and verify that the ignition timing is set to 13 degrees BTDC for the 2.0 L engine or 12 degrees BTDC for the 2.6 L engine.
Fig. 153 Testing vacuum regulator valve system
7.
While running the engine at idle disconnect the vacuum hose (yellow stripe) from the HAC and put a finger over the end of the hose to verify the
presence of vacuum.
Testing at Elevations Above 1,200 M (3,900 FT.)
