Water Temperature Switch - Rough Idle

88mazda03

Category 4
Applicable Model/s 1986-1988 RX-7
Subject ROUGH IDLE
Bulletin No. 047/88
Issued 4/22/88
Revised



DESCRIPTION

If a customer complains of a rough idle, check the water temperature switch and related wiring. The water temperature switch wiring could be damaged and may not be detected while checking voltages with the engine off.

Should you encounter the above condition, refer to the following procedures.


CHECKING PROCEDURE

1. Connect the engine signal monitor to the control unit. Refer to the 1987/1988 RX-7 Workshop Manual, page 4A-30 or 4B-31.

2. Warm up the engine to normal temperature.

3. Monitor voltage at terminal 1H for correct voltage under the following conditions:

- engine off, key on
- engine idling
- engine acceleration and deceleration in neutral

NOTE:
The voltage should be below 1.5V with warm engine.

4. If any voltage fluctuation is noted, inspect the water temperature switch wiring especially near the radiator where the harness is tie-wrapped to the oil cooler lines.

5. If open or damaged wire is found, repair as needed.