Cummins fuel supply adjustment

If the fuel supply of each cylinder in the Cummins diesel generator set is uneven (such as some cylinders having excessive fuel supply, while others have insufficient fuel supply), it will directly affect the smoothness of engine operation. The fuel injection pump can be removed and checked and adjusted on the test bench. However, if there is no test bench and it is necessary to check for uneven fuel supply, a rough inspection of the suspected cylinder's fuel supply can also be carried out. Check and adjust the method:

① Prepare two glass measuring cylinders for use. If the measuring cylinder cannot be found at the moment, two identical small bottles can also be used as substitutes.

② Remove the high-pressure oil pipe joint that connects the cylinder with the fuel injector due to excessive (or insufficient) fuel supply.

③ Remove the high-pressure pipe joint that connects the normal fuel supply cylinder to the fuel injector.

④ Insert the two oil pipe ends into two measuring cylinders (or small bottles) respectively.

⑤ Rotate the engine with the starter motor to pump oil from the fuel injection pump.

⑥ When there is a certain amount of diesel in the equivalent cylinder (or small bottle), place the measuring cylinder on a horizontal table to compare the amount of oil and determine whether the fuel supply is too large or too small. If a small bottle is used instead, it can be weighed and compared. The relative position of the fork (or ring gear) on the fuel injection pump oil quantity adjustment rod (i.e. gear rod) can be adjusted. The P_ type pump can be adjusted by rotating the flange sleeve.

During the operation of Cummins diesel generator sets, based on experience, special attention should be paid to the following points:

① Loosen the fixing screws of the fork (or ring gear, or flange sleeve), and the fuel supply can be changed by moving it slightly. Do not move it too much, otherwise it is difficult to adjust accurately (if necessary, mark the initial position first for comparison).

② After each adjustment, the tightening degree of the fixing screws must be confirmed.

③ When adjusting the fuel supply, it should be ensured that the fuel supply does not exceed the standard fuel supply. This is because the adjustment is carried out at low speeds, taking into account the influence of various factors such as oil leakage, a significant unevenness (30%) is allowed at this time. However, at high speeds, due to factors such as throttling, the allowable unevenness is relatively small (3%). If the oil quantity at low speed is higher than the standard fuel supply, the oil quantity at high speed may have significant changes, even exceeding the rated fuel supply.

④ If there is a significant difference between the maximum and minimum fuel supply on the same engine, do not adjust in a hurry. You can first swap and install the outlet valves of the two pumps for inspection and comparison. Sometimes, this can also change the fuel supply. If there is no change in the fuel supply after swapping, it is necessary to adjust the two pumps one by one.

⑤ Adjusting the fuel supply using the comparative method requires careful and meticulous operation.