Cummins ISC Quick Sheet

The Cummins ISC engine has become popular in two main applications: Vocational Trucks and Motorhomes.

Many city, county, and state trucks use the ISC engine to power their dump trucks and plow trucks. The ISC engine also features very versatile engine ECM parameters, so customizing the engine to the application is quite easy. Some popular parameters that can be adjusted are:


1.) Engine PTO settings: Can be programmed to allow preset engine speed (RPM) at the touch of a button. This ensures that the engine operates at the preferred RPM when releasing load and operating hydraulics.
2.) Max engine speed without Vehicle Speed Signal (VSS): Limits the engine's RPM when vehicle is stationary, preventing unnecessary engine wear and decreasing fuel consumption.
3.) Remote Throttle Signal: Allows add-on items such as a remote accelerator to be used when controlling engine RPM is necessary outside of the vehicle cab (Example: boom operator)

For the Cummins diesel motorhome, the Cummins ISC engine is almost a legend. Not only does it offer great fuel economy, the maintenance schedule is very forgiving. Besides such options as a factory exhaust brake, the Cummins ISC engine is supported by Cummins dealers all across the nation.

Beginning in 1998, Cummins introduced the ISC based off the earlier mechanical 8.3 C-series engine. The original ISC engine featured a Cummins Accumulator Pump System (CAPS). This CAPS pump was a computer controlled injection pump, with individual fuel lines to each injector.

In 2003, Cummins released the updated ISC engine. Among other differences, the most significant was the change to the High Pressure Common Rail (HPCR) fuel system. The new fuel system eliminated the CAPS injection pump, relying on electronic controlled injectors to actuate fuel.

Use the charts below for useful information for the ISC engine:

Engine Ratings

Advertised hp @ rpm Peak Torque lb-ft @ rpm Governed Speed
240 - 330 660 - 950 @ 1300 2200-2600

Maintenance Schedule (CAPS or HPCR Fuel System)
(Why Fleetguard Filters?)
Oil Filter 15,000 Miles, 500 Hours, or 6 Months
Fuel Filter 15,000 Miles, 500 Hours, or 6 Months
Valve Adjustment 150,000 Miles, 5000 Hours, or 4 Years


Filter Part Numbers (Fleetguard Numbers)
HPCR (03 & up) CAPS (98-03)
Oil Filter LF9009 LF9009
Fuel Filter (Water Seperator) FS1003 FS1022
Fuel Filter LF9009 FF5488


Useful Specs (CAPS or HPCR Fuel System)
Intake Valve Clearance .012"
Exhaust Valve Clearance .022"
Engine Brake Clearance .090"
Firing Order 1-5-3-6-2-4
Oil Pressure 10psi (Idle), 30psi (Rated RPM)

Fuel Pressure Specs (Minimum)

HPCR CAPS
Lift Pump 5 psi Cranking 5 psi Minimum
Gear Pump 10 psi Cranking
70 psi @ rated speed
10 psi Cranking


Return to Cummins Diesel Engines

Return from Cummins ISC to Home Page