Make sure the carburetors are in sync before checking idle speed and mixture condition. You will also need to remove the ECU fuse from the fuse box for 10 seconds to reset the control unit after this procedure is complete.
1. Start the engine and warm it up to normal operating temperature. The fans should turn on at least once.
2. Disconnect the vacuum hose from the control air inlet diaphragm and pinch or plug the end of the hose.
3. Attach a tachometer. Check that the quick release lever is. was not opposite the cam fast x.x.
4. Check the idle speed. with all power consumers switched off. Turnover x.x. should be 800±50 rpm (750+50 rpm with automatic transmission). Adjust idle speed, if necessary, by turning the throttle adjusting screw.
If the speed x.x. excessively high, check throttle control.
5. On 1987 vehicles with automatic transmission only, disconnect the connector from the frequency solenoid "A" and use a jumper to connect the valve to 12V. On all other vehicles, disconnect the two connectors from the EACV valve, disconnect the hose from the vacuum manifold, and plug the end of the hose.
6. Disconnect the vacuum tubes and connect the bottom hose to the air control valve A. Disconnect the vacuum hose from the idle throttle control. air conditioning. Disconnect the air cleaner intake tube from the air intake duct.
7. Insert the enriched propane hose into the inlet tube about 10 cm.
Propane is a flammable gas. Do not smoke or work near open flames. Have a dry powder fire extinguisher handy.
8. With the engine running at idle, depress the button on top of the propane unit, then slowly open the control valve until maximum engine RPM is obtained. Engine speed should increase when propane injection starts.
Open the propane control valve slowly; if the engine is started too hard, the engine may stall.
9. Maximum increase in speed when enriched with propane:
- 1984-86 with a manual gearbox - at 45±25 rpm;
- 1984-86 with automatic transmission - at 110±25 rpm (on D3 or D4);
- 1987 with a manual - at 65 + 25 rpm;
- 1987 with automatic - at 130+25 rpm (on D3 or D4);
- 1988-90 with manual - at 170x20 rpm;
- 1988-90 with automatic transmission - at 50 + 10 rpm.
10. If the revolutions have changed in the proper way, the procedure is completed. Remove test equipment and attach tubes and hoses. If the engine speed does not increase to specification, the mixture needs to be adjusted. On Preludes through 1987, remove the carburetors and use steps 11-13 below. On later vehicles, the plugs can be removed without removing the carburetors; continue from step 15.
11. Place the stopper on the tip of the gimlet so that only 3 mm remains. Drill holes in the center of each plug.
If you drill too deep, the tip of the gimlet can damage the mixture adjustment screw.
12. Drive 5mm metal screws into the plugs.
13. Grasping the screw heads with pliers, remove the plugs.
14. Install carburetors.
15. Start the engine and warm it up to normal operating temperature. Fan (s) should turn on at least once.
16. Recheck the maximum RPM for propane enrichment. If the mixture is too rich, turn both mixture adjustment screws 1/4 turn counterclockwise.
17. Close propane control valve.
18. Run the engine at 2500 rpm for 10 seconds to stabilize mixture conditions, then check the idle speed. Adjust RPM if needed.
19. On 1984-86 models, remove the propane kit and attach the air inlet control orifice hose. Install new plugs in the x.x mixture adjustment screw holes.
20. On 1987-89 models, disconnect the #5 vacuum hose from the air intake valve and plug the end.
21. On a 1987 Prelude, disconnect the #22 top vacuum hose from the air leak solenoid valve on the air control bracket and plug the end. Connect a vacuum gauge to the solenoid valve.
22. With the engine running at idle, depress the button on the top of the propane unit, then slowly open the propane control valve and check the vacuum. The vacuum must be developed.
23. If there is no vacuum, check the air leakage solenoid valve.
24. Check thermal valve C.
25. Remove the propane enrichment kit and reconnect the connectors.
26. On 1988-90 cars equipped with air conditioning, the speed x.x. must be checked with the air conditioner on at the end of the procedure. If adjustment is necessary, remove the small cover from the adjustment screw and make an external adjustment.