Caterpillar IT28G Low Power Issue Beyond 1400 RPM

[MikePhua]

The Caterpillar IT28G integrated tool carrier is a powerful and versatile piece of equipment widely used in construction and material handling. However, some operators experience an issue where the engine loses power or “has no power” past around 1400 RPM, causing skipping and significant performance loss. This article explores potential causes, diagnostic tips, and solutions to address this critical problem.
Symptom Overview

• The engine appears to operate normally at idle and low RPM.
  
• Once the RPM approaches or exceeds 1400, the engine begins to skip, lose power, and fails to produce expected torque.
  
• The machine struggles in tasks requiring higher engine speeds and load.
  

Common Causes

• Fuel Delivery Issues: Inadequate fuel supply or pressure to the engine at higher RPMs causes fuel starvation, leading to skipping and power loss.
  
• Air Intake or Exhaust Blockage: Restricted airflow or clogged exhaust after-treatment components reduce engine breathing, limiting power.
  
• Hydraulic Loading and Brake Interactions: The IT28G’s hydraulic brake system involves accumulators that charge and discharge at certain pressures. Excessive brake use can redirect hydraulic flow, affecting engine cooling fan speed and system pressure, indirectly causing performance drops.
  
• Electronic Engine Controls: Faulty sensors or ECM (engine control module) errors may reduce power output or torque limits to prevent damage.
  
• Torque Converter Issues: The transmission’s torque converter may fail to absorb engine power properly at certain RPMs, leading to stalling or power drop.
  

Diagnostic Strategies

• Check fuel filters, pumps, and lift pumps for proper operation and flow rates.
  
• Inspect air filters and exhaust systems for blockages or soot accumulation.
  
• Monitor hydraulic system pressures and accumulator charging cycles during operation.
  
• Use diagnostic tools to read trouble codes from the engine control module.
  
• Assess torque converter function by testing stall speeds and transmission responsiveness.
  

Technical Terms Explained

• Torque Converter: A fluid coupling in automatic transmissions transferring rotating power and multiplying torque.
  
• Accumulator: A hydraulic component storing energy under pressure to smooth out hydraulic system performance.
  
• ECM (Engine Control Module): The computer controlling engine parameters and diagnostics.
  
• Fuel Starvation: Insufficient fuel delivery causing engine misfire or power loss.
  
• Hydraulic Fan Drive: A system powering cooling fans via hydraulic motors, often linked to engine and brake operations.
  

Solutions and Maintenance

• Replace clogged fuel filters and ensure fuel quality.
  
• Clean or replace air intake and exhaust filters periodically.
  
• Service or rebuild the torque converter if its stall speed is abnormal.
  
• Calibrate or repair hydraulic brake systems to prevent undue fan slowdowns.
  
• Update ECM software or sensors if errors are detected.
  
• Regularly maintain accumulators per manufacturer guidelines to ensure readiness.
  

A Real-World Example
An IT28G operator noticed power loss after 1400 RPM coinciding with heavy brake use on steep grades. Investigation revealed accumulator pressures were cycling excessively, causing fan slowdowns that overheated the engine and triggered protective power-reduction modes. After servicing accumulators and adjusting brake use, engine power returned to normal.
Summary
Power loss in the Caterpillar IT28G beyond 1400 RPM often results from complex interactions of fuel delivery, hydraulic braking systems, electronic controls, and torque converter functionality. Thorough diagnostics focusing on these systems, proactive maintenance, and understanding how hydraulic and engine controls interplay are key to restoring full power and reliable machine operation in demanding work environments.