1998/06/08 Caterpillar

914G (7ZM, 9WM) Wheel Loaders;
IT14G (8ZM, 1WN) Integrated Toolcarriers

Formerly, there were no boost pressure specifications for the turbocharged 3054 engines in these machines. This made it difficult to troubleshoot "low power" complaints. The 914G Wheel Loaders and IT14G Integrated Toolcarriers are Hystat machines, therefore, no torque converters are used.

In these machines, the turbocharged 3054 machine engine will produce:

* 41 ± 7 kPa (6.0 ± 1.0 psi) boost pressure at High Idle;

* 55 ± 7 kPa (8.0 ± 1.0 psi) at single engine stall;

* 72 ± 7 kPa (10.5 ± 1.0 psi) at double stall (transmission stall and implement relief), (approximately 2250 rpm).

Illustration 1.
107-4702 Brake Control Group with the former master cylinder group. See Chart 1.

Use these specifications when troubleshooting a low power complaint on one of these engines.

To properly stall the engine against the transmission for a single engine stall, the actuating rod for the Hystat inching valve must first be disconnected to prevent the transmission from neutralizing. The actuating rod is located near the master cylinder. There are two master cylinder configurations that have been used on these machines.

Refer to Illustration 1. The former configuration was used with the effectivity listed in Chart 1. Disconnect inching control actuating rod (1) at the end closest to the brake cable. Dimension A is 220.1 ± 2.0 mm (8.67 ± .08 in).

Illustration 2.
The 107-4702 Brake Control Group with the current master cylinder group. See Chart 2.

Refer to Illustration 2. This configuration was used with the effectivity listed in Chart 2. Use Quick Disconnect (1) on the inching valve lever to detach the inching valve. Dimension A is 207.9 ± 2 mm (8.19 ± .08 in).

Single Engine Stall Procedure

NOTE: Make sure the inching valve is closed during the stall test.

1. Remove the cold start heater and install a suitable fitting to measure the boost pressure. A 7W-6217 Adapter may be used to adapt the 7/8 inch - 14 threaded port to the 1/8 inch - 27 pipe thread.

2. Apply the service brakes with the parking brake disengaged.

3. The transmission is in Forward.

4. Run the engine at full throttle (approximately 2300 rpm). No wheel rotation is allowed while the engine is at full throttle.

5. Measure the boost pressure at the port where the cold start heater (thermostart) is installed.

NOTE: Variations in altitude, barometric pressure, fuel quality, humidity, and air temperature will have affects on boost pressure. Be aware of these affects when conducting the test.

NOTE: When reinstalling the cold start heater, be sure to remove all the air from the fuel line to the cold start heater while priming the engine fuel system with the hand priming pump. Failure to remove all the air from the line may result in damage to the cold start heater.

NOTE: This article describes the test for the loss of power for the engine only.