For owners and enthusiasts of the 1999 24v Cummins ISB engine, understanding the diagnostic capabilities and potential modifications is crucial. This engine, while robust, benefits from informed maintenance and upgrades. Let’s delve into some key aspects, particularly concerning diagnostics and performance enhancements.
When it comes to fuel delivery modifications, a popular upgrade is the Fuel Air Separation System (FASS) pump. For optimal performance and longevity of your FASS system, mounting it as close to the fuel tank as possible, and ideally below it, is generally recommended. This configuration aids in priming and reduces strain on the pump. Furthermore, consider eliminating the factory lift pump located on the engine block when installing a FASS system to streamline fuel flow and prevent potential issues. While FASS pumps are widely praised, some users have reported occasional motor failures, suggesting due diligence in installation and maintenance.
Regarding diagnostics, the 1999 Cummins ECM does indeed support OBD2 connectivity. Despite being an earlier system, the ECM communicates on the same CCD bus as other vehicle modules like the PCM, BCM, radio, and instrument cluster. This means that the OBD connector provides a port to access the ECM for diagnostic purposes. It’s generally assumed that the ECM utilizes the J1962 protocol, common to other modules on the bus, for communication. This is how aftermarket tuners typically interface with the ECM. For those looking to use Cummins Insite or the J1939 protocol, a Cummins bus connector might be necessary, or exploring methods to enable Insite communication through the J1962 channel would be required. For in-depth technical inquiries, consulting directly with engineering experts at tuning companies, rather than general tech support, is advisable for nuanced solutions.
ECM variations exist depending on the application of the Cummins engine. While the Dodge truck ECM variant often utilizes a comprehensive pinout configuration, ECMs in applications like buses may differ. Bus applications might employ ECMs with multiple connectors to accommodate the wiring demands of individual gauges and additional accessories, contrasting with the CCD data bus system used in Dodge trucks for gauge clusters. These application-specific requirements often dictated ECM configurations with varying connector counts.
In terms of performance, engine power levels are largely determined by the PCM calibration. While different horsepower ratings might involve component variations such as pistons, injectors, injection pumps, and manifolds to achieve and sustain those ratings, applying a higher horsepower tune to a lower-rated engine can still yield performance gains. For example, loading a 275 horsepower tune onto a 210 horsepower engine will likely result in increased power, although the exact extent of the gain may vary and might not fully reach the 65 horsepower differential. Upgrading hard parts in conjunction with tuning is recommended to enhance engine durability when aiming for higher performance levels.
So-called “comp boxes” represent a different approach to performance enhancement. These devices operate by intercepting and manipulating sensor inputs to the ECM, effectively misleading the ECM into perceiving altered operating conditions. While they can produce noticeable performance changes, they do not modify the ECM’s calibration directly. This method is viewed with skepticism by some, who prefer direct ECM tuning for more controlled and potentially safer performance modifications.
