Air/Fuel Mixture: Adjustments

WARNING:Do not smoke during this procedure. Keep any open flame away from the work area.

NOTE: This procedure requires a propane enrichment kit.
Check that the carburetors are synchronized properly, and that the warning light and self diagnosis indicator do not show any trouble codes before making fuel mixture adjustments.

Fig. 29 Cap Off The Hose To The Electronic Air Control Valve (EACV):

1. Disconnect the 2P connector from the EACV and disconnect the hose from the vacuum hose manifold, then cap the hose end.

Fig. 30 Remove The Cap From The Vacuum Manifold (Or The Hose If Car Has A/C):

2. Disconnect the cap from the vacuum hose manifold. If equipped with an air conditioner, disconnect the vacuum hose from the vacuum hose manifold.
3. Disconnect the air cleaner intake tube from the air intake duct.
4. Note the engine speed after starting the engine and that the idle speed is stable.

Fig. 31 Propane Enrichment Kit Installation:

5. Insert the hose of the propane enrichment kit into the intake tube about 4 inches.

NOTE: Check that the propane bottle has adequate gas before beginning test.

Fig. 32 Propane Enrichment To RPM Change Graph.:

6. With the engine idling, slowly open the propane control valve to obtain the maximum engine speed.
7. Engine speed should increase as the percentage of propane injected goes up.

NOTE: Open the control valve slowly, a sudden burst of propane may stall the engine.

8. Compared to the idle speed noted in step 4.

RPM increase should be:
Manual Transmission: 170 +/- 20 rpm
Automatic Transmission: 50 +/- 10 rpm (in "D")

a. If the engine speed does not increase per specification, the mixture is improperly adjusted. Go to step 10.
b. If engine speed increases per specification, go to step 11.

Fig. 33 Mixture Adjustment Screw And Anti-Tamper Cap:

10. Remove the mixture adjusting screw hole caps, and recheck the maximum propane enriched rpm.
a. If the propane enriched speed is to low, the mixture is to rich. Turn both mixture screws 1/4-turn clockwise and recheck.
b. If the propane enriched speed is to high, the mixture is to lean. Turn both mixture screws 1/4-turn counterclockwise and recheck.
11. Reconnect the connector, and cap or hose. Close the propane control valve.

Fig. 34 Idle Speed Adjustment Screw:

12. Remove EFI-ECU fuse for 10 seconds to reset the control unit, and recheck the idle speed.

Idle speed should be:
Manual Transmission 800 +/- 50 rpm
Automatic Transmission 750 +/- 50 rpm (in "D")

a. If the idle speed is as specified, go to step 13.
b. If the idle speed is not as specified, adjust by turning the throttle stop screw, then repeat step 10.

13. Remove propane enrichment kit and reconnect air cleaner intake tube on the air intake duct.
14. Reinstall the mixture adjusting screw hole cap.
15. If equipped with air conditioner, check the idle speed with the A/C on.

Idle speed should be: 750 +/- 50 rpm

Adjust the idle speed, if necessary, by turning the adjusting screw.