Propane Idle Mixture - Adjustment Procedure

87chrysler5

Models


1985-1986 Import Vehicles Equipped With Carburetors


Subject

Propane Idle Adjustment


Index

EMISSIONS


Date

June 23, 1986


No.

25-02-86 REVISION A

P-2295
This technical service bulletin supersedes #25-02-86, which should be removed from your files.


The procedures and specifications for using propane to adjust idle mixture are described below:

1. Remove carburetor from the engine and place in a vise to enable the idle mixture screw concealment plug to be removed.

2. Reinstall the carburetor on the engine.

3. Start engine and allow it to reach normal operating temperature.

4. Turn off the engine and disconnect the negative battery terminal for five seconds, then reconnect the cable.

5. If so equipped, unplug the oxygen sensor connector located near the exhaust manifold.

6. Start engine and operate vehicle for five minutes at a vehicle speed of 30 mph or run the engine at 2000-3000 rpm for five seconds. Lights, cooling fan, and all accessories must be off and transmission in neutral.

7. Allow the engine to operate at curb idle for two minutes.

Ignition Timing:

8. Check ignition timing and adjust as necessary. See specifications on next page.

NOTE: a. Ignition timing marked with * is for production vehicles built in April, 1985 or later. Ignition timing for production vehicles built before April, 1985, is 3~ BTDC +/- 2~/ [8~ BTDC +/- 2~].

b. In the above table, the ignition timing in [ ] shows actual ignition timing when the vehicle is equipped with a dual diaphragm type distributor. However, it is applicable to high altitude vehicles only.

c. M/T: Manual Transmission
A/T: Automatic Transmission
9. Disconnect the fresh air duct from the air cleaner and insert the propane supply hose into the air cleaner about 4-6 inches.

10. Make sure both valves on the propane bottle are closed and that it is upright and in a safe location.

11. Open the main propane valve and slowly open the propane metering valve until maximum engine speed is achieved. Excessive amounts of propane will cause engine speed to reduce. "Fine tune" the metering valve to obtain highest engine rpm.



12. With the propane still flowing, adjust idle speed screw to obtain specified enriched rpm shown below. "Fine tune" the propane metering valve again to obtain the highest engine rpm. If there has been a change in the enriched rpm, readjust the idle speed screw to obtain the specified enriched rpm.
NOTE: a. First 300 miles/after 300 miles.
13. Turn off the propane main valve and allow engine speed to stabilize.

14. Slowly adjust the idle mixture screw to obtain the specified curb idle speed.

15. Recheck maximum enriched idle speed again by using the propane metering valve. If the enriched speed varies by more than 25 rpm than the specified enriched rpm, perform Steps 11 through 14 above.

16. Turn off both valves and remove the propane bottle and hose.

17. Reconnect the O2 sensor wire previously disconnected in Step 5 above.

18. Reinstall the idle mixture concealment plug removed in Step 1 above.

19. Hook up the fresh air duct to the air cleaner.

20. Road test vehicle to insure all systems are operating normally.


POLICY: Information only