New High Quality Diesel Injector 386-1771 20R-1280 386-1774 20R-1282 389-1969 386-1779 20R-1263 392-0200 20R-1264 11R-0278 For CAT C3500B

Mechanical structure damage
1. Increased wear of cylinder and piston components
Pressure is too low:
Poor fuel atomization causes unburned fuel to flush the cylinder wall in liquid form, dilute the lubricating oil film, and aggravate the abrasion of the piston ring and cylinder liner (commonly known as "cylinder pulling").
Unburned fuel penetrates into the crankcase, dilutes the engine oil, resulting in reduced lubrication performance and accelerated wear of components such as the crankshaft and connecting rod bearings.
Pressure is too high:
The combustion pressure peak is early and too high (such as pre-ignition or detonation), and the piston top and cylinder head are subjected to abnormal impact loads, which may cause the piston ring to break, the piston top to burn or crack.
2. Valve and combustion chamber damage
Pressure is too high:
The combustion temperature rises suddenly (up to 2000℃ or more), exceeding the tolerance limit of the valve material, resulting in valve head burning, sealing surface deformation, and even valve stem breakage.
High-temperature and high-pressure gas may backflow through the valve clearance and damage the valve spring or rocker arm mechanism.
3. Wear and jam of the injector itself
Pressure is too low:
Impurities in the fuel (such as iron filings and colloid) are easily deposited on the needle valve sealing surface, resulting in loose closure and dripping, which further aggravates the pressure drop.
Pressure is too high:
High-pressure fuel repeatedly impacts the needle valve and the valve seat, causing wear, scratches or pits on the sealing surface, resulting in the inability to maintain pressure (such as the needle valve stuck in the open position).

Decreased combustion efficiency and power performance
1. Insufficient power output
Pressure is too low:
Poor fuel atomization causes uneven formation of the mixture, slows down the combustion speed, and reduces the effective pressure in the cylinder, resulting in a decrease in engine power (possibly 10%-30%).
The manifestation is that the vehicle is unable to climb the slope, the acceleration is slow, and the maximum speed cannot reach the standard when driving at high speed.
Pressure is too high:
The injection advance angle is too large (such as improper adjustment of the mechanical injector), the combustion breaks out prematurely before the top dead center, the upward resistance of the piston increases, and the "reverse drag" phenomenon occurs, and the power decreases instead.
2. Abnormal combustion and energy waste
Pressure is too low:
The fuel is not fully burned to form soot particles, and part of the fuel is discharged with the exhaust gas (black smoke), which reduces energy utilization and may increase fuel consumption by 20%-40%.
Pressure is too high:
The fuel atomization is too fine, resulting in too fast combustion rate, sudden increase in cylinder pressure, energy loss in the form of shock waves (similar to gasoline engine knock), and reduced thermal efficiency.

Emission pollution and post-treatment system failure
1. Excessive emissions
Pressure is too low:
Incomplete combustion leads to a surge in soot (PM) and carbon monoxide (CO) emissions. When black smoke is obvious, the soot concentration can exceed the regulatory limit by 5-10 times.
Pressure is too high:
High-temperature combustion promotes the generation of nitrogen oxides (NOx) (such as more than 800ppm), which may cause the SCR system (urea injection) of the National VI model to overload or fail.
2. The post-treatment system is blocked or damaged
Pressure is too low:
Unburned soot particles are deposited in the DPF (diesel particulate filter), shortening the regeneration cycle. Frequent regeneration will accelerate the aging of the DPF carrier and even block the exhaust pipe.
Pressure is too high:
Metal debris (such as worn injector part particles) produced by abnormal combustion may enter the DOC (oxidation catalyst) with the exhaust gas, causing catalyst poisoning and failure.

Fuel and lubrication system chain failure
1. Fuel system leakage risk
Pressure is too high:
Common rail pipes and high-pressure oil pipes are subjected to overpressure loads for a long time, which may cause the interface seal ring to age and the pipeline to crack, causing fuel leakage and even fire risks.
Frequent opening of the pressure limiting valve will accelerate the wear of the valve seat and cause pressure control failure (such as pressure loss in the common rail system).
2. Deterioration of engine oil performance
Pressure is too low:
After the oil is diluted by fuel, the viscosity of the oil decreases (such as the viscosity of SAE 15W-40 drops to close to 5W-30), and the lubrication protection ability is lost, which may cause serious mechanical accidents such as "braking".
The sulfur component in the fuel reacts with the oil additive to generate acidic substances, which corrode the metal parts inside the engine.

Starting and running stability problems
1. Difficulty in starting or failure to start
Pressure is too low:
During cold start, the fuel evaporation conditions are poor, and poor atomization makes it difficult for the mixture to ignite. It may take multiple starts or external forces (such as starting fluid) to be used.
Pressure is too high:
The injection time is too early, and the fuel has been injected before the compression end temperature reaches the ignition point, resulting in a "wet cylinder" (unburned fuel accumulates in the cylinder), which makes it impossible to start.
2. Unstable idle speed and abnormal vibration
Pressure fluctuation:
The amount of fuel injection in each cylinder is uneven (such as the periodic decrease in the pressure of a cylinder), resulting in a disordered combustion sequence, the idle speed fluctuates by more than ±100rpm, and the engine shakes violently.
It may be accompanied by the phenomenon of "wandering" (speed fluctuates), affecting driving comfort and reliability.

Maintenance cost and economic impact
Short-term cost:
Frequent replacement of injector parts (such as needle valve-valve seat), common rail pressure sensor and other components, the cost of a single maintenance can reach thousands of yuan.
The cleaning or replacement cost of the post-treatment system (such as DPF, SCR) is high (DPF regeneration failure may require overall replacement, the cost exceeds 10,000 yuan).
Long-term loss:
The engine overhaul cycle is shortened (such as normal overhaul mileage of 500,000 kilometers, abnormal wear may be advanced to 200,000-300,000 kilometers), and the overall service life is reduced by 30%-50%.
Prevention and countermeasures
Regular maintenance:
Injector calibration (mechanical injector) or data flow analysis (common rail system) every 50,000-80,000 kilometers to ensure that the pressure is within the standard range (such as the common rail system idle pressure is about 20-50MPa, and 120-160MPa during acceleration).
Fuel quality control:
Use high-quality diesel with sulfur content less than 10ppm to avoid impurities clogging the injector nozzle or wearing precision parts.
Timely fault response:
When abnormalities such as black smoke and abnormal noise are found, stop the machine for inspection immediately to avoid the expansion of the fault (such as cylinder scuffing due to low pressure, which increases the maintenance cost by 5-10 times).