Diesel Data: Automotive Repair

Mechanical System Tests

MECHANICAL SYSTEM TESTS

a. Measure the stall speed.
The object of this test is to check the overall performance of the transaxle and engine by measuring the stall speeds in the D and R positions.

NOTE:
- Perform the test at the normal operating ATF (Automatic Transmission Fluid) temperature 50 °C - 80 °C (122 °F - 176°F).
- Do not continuously run this test longer than 5 seconds.
- To ensure safety, conduct this test in a wide, clear level area which provides good traction.
- The stall test should always be carried out in pairs. One technician should observe the conditions of wheels or wheel stoppers outside the vehicle while the other is doing the test.

1. Chock the 4 wheels.
2. Connect an OBD II scan tool or hand-held tester to DLC3.
3. Fully apply the parking brake.
4. Keep your left foot pressed firmly on the brake pedal.
5. Start the engine.
6. Shift into the D position. Press all the way down on the accelerator pedal with your right foot.
Quickly read the stall speed at this time.
Stall speed: 2,350 ± 200 rpm

7. Do the same test in R position.
Stall speed: 2,350 ± 200 rpm




Evaluation

b. Measure the time lag.
When the shift lever is shifted while the engine is idling, there will be a certain time lapse or lag before the shock can be felt. This is used for checking the condition of the No. 2 one-way clutch, reverse clutch, forward clutch, and 1st & reverse brake.

NOTE:
- Perform the test at the normal operating ATF temperature 50 °C - 80 °C (122 °F - 176 °F).
- Be sure to allow 1 minute interval between tests.
- Take 3 measurements and take the average value.

1. Connect an OBD II scan tool or hand-held tester to DLC3.
2. Fully apply the parking brake.
3. Start and warm up the engine and check idle speed.
Idle speed: approx. 700 rpm (In N position and A/C OFF)
4. Shift the shift lever from N to D position. Using a stop watch, measure the time from when the lever is shifted until the shock is felt.
Time lag: N -> D Less than 1.2 seconds
5. In the same manner, measure the time lag for N -> R.
Time lag: N -> R Less than 1.5 seconds




Evaluation (If N -> D time or N -> R time lag is longer than specified)