If your working on the Cummins engine:
Signature
ISX
QSX15

CM870

then you have just found the workshop manual for you, massive manual covering everything you need to know in the service and repair of your engine.

Sections in this manual:
Section i - Introduction
 About the Manual
How to Use the Manual
 Symbols
Illustrations
General Safety Instructions
General Repair Instructions
General Cleaning Instructions
Acronyms and Abbreviations

Engine and System Identification
Engine Identification
Engine Diagrams

Familiarization
Complete Engine - Overview
Cylinder Block - Overview
Cylinder Head - Overview
Rocker Levers - Overview
Fuel System - Overview
Flow Diagram, Fuel System
Injectors and Fuel Lines - Overview
Lubricating Oil System - Overview
Flow Diagram, Lubricating Oil System
Cooling System - Overview
Flow Diagram, Cooling System
Air Intake System - Overview
Flow Diagram, Air Intake System
Exhaust System - Overview
Flow Diagram, Exhaust

Compressed Air System - Overview
Flow Diagram, Compressed Air System
Electrical Equipment - Overview
Engine Testing - Overview
Vehicle Braking - Overview

Troubleshooting Symptoms
Troubleshooting Procedures and Techniques
Troubleshooting Symptoms Charts
Air Compressor Air Pressure Rises Slowly
Air Compressor Cycles Frequently
Air Compressor Noise is Excessive
Air Compressor Pumping Excess Lubricating Oil into the Air System
Air Compressor Will Not Maintain Adequate Air Pressure (Not Pumping

Continuously)
Air Compressor Will Not Pump Air
Air Compressor Will Not Stop Pumping
Aftertreatment Diesel Particulate Filter - Excessive Soot Loading
Aftertreatment Diesel Particulate Filter - Excessive Ash Cleaning
Alternator Not Charging or Insufficient Charging
Coolant Loss - External
Coolant Loss - Internal
Coolant Temperature Above Normal - Gradual Overheat
Coolant Temperature Above Normal - Sudden Overheat
Coolant Temperature Below Normal
Coolant in the Lubricating Oil
Crankcase Gases (Blowby) Excessive
Crankcase Coalescing Filter - Frequent Replacement
Engine Brake Does Not Operate
Engine Brake - Low Retarding Power or Slow to Activate
Engine Brake - One or More Cylinders Braking with Power Switch Off
Engine Decelerates Slowly
Engine Noise Excessive
Engine Noise Excessive - Combustion Knocks
Engine Noise Excessive - Connecting Rod
Engine Noise Excessive - Main Bearing
Engine Noise Excessive - Piston
Engine Noise Excessive - Turbocharger
Engine Shuts Off Unexpectedly or Dies During Deceleration
Engine Speed Surges in PTO or Cruise Control
Engine Starts But Will Not Keep Running
Engine Will Not Crank or Cranks Slowly (Air Starter)
Engine Will Not Crank or Cranks Slowly (Electric Starter)
Engine Will Not Shut Off
Fuel Consumption Excessive
Fuel in Coolant
Fuel in the Lubricating Oil
Intake Manifold Air Temperature Above Specification
Intake Manifold Pressure (Boost) is Below Normal
Lubricating Oil in the Fuel
Lubricating Oil Consumption Excessive
Lubricating Oil Contaminated
Lubricating Oil Filter Plugged
Lubricating Oil Pressure High
Lubricating Oil Pressure Low
Lubricating Oil Sludge in the Crankcase Excessive
Lubricating Oil Temperature Above Specification
Lubricating or Transmission Oil in the Coolant
Turbocharger Leaks Engine Oil or Fuel
Stationary Regeneration - Will Not Activate
Aftertreatment Diesel Particulate Filter - Excessive Automatic and/or

Stationary Regeneration
Stationary Regeneration - Will Not Complete
 Troubleshooting Overview

 Troubleshooting Symptoms  
Engine Performance Troubleshooting Tree - Signature and ISX CM870
Engine Performance Troubleshooting Tree - ISX with CM871
Fuel Economy Troubleshooting Tree
Fuel Economy Troubleshooting Tree
Vibration Excessive

Complete Engine
Service Tools
Engine Removal
Engine Installation
Engine Storage - Long Term

Engine Disassembly  
 Cooling System
Lubricating Oil System
Engine Removal
Lubricating Oil Filter (Spin-On)
Coolant Filter
Fuel Filter (Spin-On Type)
Rocker Lever Cover
Starting Motor
Drive Belt, Cooling Fan
Belt Tensioner, Automatic (Water Pump)
Fan Hub, Belt Driven
Fan Support
Drive Belt, Refrigerant Compressor
Idler Pulley, Refrigerant Compressor
Belt Tensioner, Refrigerant Compressor, Automatic
Refrigerant Compressor
Crankcase Breather (External)
Lubricating Oil Fill Tube
Lubricating Oil Dipstick Tube
EGR Mixer
Air Intake Connection
ECM Cooling Plate, Fuel Cooled
Aftertreatment Injector Lines
Aftertreatment Fuel Shutoff Manifold
Integrated Fuel System Module (IFSM)
Turbocharger Air Shutoff Valve Filter
Turbocharger, Variable Geometry Control Valve Air Supply Line
Turbocharger Control Shutoff Valve Filter Head
Turbocharger, Variable Geometry Actuator Air Supply Line

 Aftertreatment Adapter Pipe
Aftertreatment Fuel Injector
Turbocharger, Variable Geometry Actuator
Turbocharger Coolant Hos

Turbocharger
Heat Shield
EGR Cooler Coolant Lines
EGR Valve Coolant Lines
EGR Valve
EGR Valve Mounting Bracket
 Exhaust Gas Pressure Sensor Tube
Exhaust Gas Pressure Sensor Adapter
Exhaust Manifold, Dry
EGR Connection Tubes
EGR Cooler
Lubricating Oil Cooler
Engine Lifting Brackets
Coolant Thermostat Housing
Coolant Thermostat
Alternator
Alternator/Refrigerant Compressor Mounting Bracket
Refrigerant Compressor Mounting Bracket
Water Inlet Connection
Water Pump
Rocker Lever Assembly
Injector
 Vibration Damper, Viscous
Gear Cover, Upper
Crankshaft Seal, Front
Gear Cover, Lower
Air Compressor Coolant Lines
Air Compressor
Engine Base Timing
Overhead Camshaft, Valve
Overhead Camshaft, Injector
Cylinder Head
Engine Support Bracket, Front
Idler Gear, Lower Scissor
Lubricating Oil Pan
Lubricating Oil Suction Tube (Block-Mounted)
Block Stiffner Plate
Piston Cooling Nozzle
Piston and Connecting Rod Assembly
Bearing, Connecting Rod

Piston Rings
Flywheel
Crankshaft Seal, Rear
Flywheel Housing
Flywheel Housing, REPTO
Gear Housing, Front
Lubricating Oil Pump
Crankshaft
Bearings, Thrust
Bearings, Main
Cylinder Liner