3512B Petroleum Engines Caterpillar

Checking Engine Cylinders with an Electronic Service Tool

Usage:

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Table 1
Tools Needed	Quantity
Electronic Service Tool	1
7X-1701 Communications Adapter with SPM For Communications Adapter NEXG4523	1
139-4166 Data Link Cable	1
7X-1686 Cable	1

The condition of individual cylinders may be checked electronically. The cylinders may be checked by cutting out the cylinders with an electronic service tool. A weak cylinder or a dead cylinder may be found in this manner.

Connect the electronic service tool and the communication adapter to the data link connector.
Set the engine speed and load the engine so that the engine is loaded to a 50 percent load (Minimum).
Select the "Diagnostic Tests" screen from the main menu and then select "1-Cylinder Cutout".
Observe the "Injection Duration" and "Fuel Position"that is displayed on the electronic service tool screen. The injector cartridge valve is energized during a period of time that is known as the injection duration. The Fuel Position represents the amount of fuel that is being injected.
Use the arrow keys in order to highlight each cylinder. Then press "return". The display should read "CUTOUT" next to the cylinder number. Observe the numbers for the duration and the fuel position as each cylinder is cut out. Compare these numbers to the numbers that were recorded for the duration and the fuel position in Step 4. When a cylinder is cut out, the other cylinders must work harder in order to maintain the current engine speed and load. The ECM automatically increases the duration and the fuel position in order to maintain the engine rpm. If there is an electrical problem with an injector solenoid or wiring an indication may appear on the electronic service tool such as "OPEN" or "SHORTED". Refer to the Electronic Troubleshooting for troubleshooting the Electronic Control System.
If a cylinder is cut out and the duration and the fuel position do not increase, the cylinder produces less power or the cylinder does not produce power. If a cylinder is cut out and the duration and the fuel position do not increase as much as the other cylinders, that cylinder produces less power or that cylinder does not produce power.
This test may also be performed at the rated engine load. When rated load is used, the duration number will not increase when the cylinders are cut out. Instead, the engine speed will decrease. The speed will decrease because the engine is at the rated power. Increasing the fuel would increase the engine's power output above the rated power.