Are you the local Cummins Diesel expert? Be prepared the next time a no-start or high return flow situation rolls into your service bay with this Cummins diesel injector tool.

These tools are a "must have" for anyone who works on common rail fuel systems. When a common rail engine will not start, the very first thing to check is fuel rail pressure. If the pressure is less than spec, one of the most likely causes is a defective injector that is returning excess fuel back to the tank. A return flow volume test will verify if excessive return flow is the problem. A cap is then used to identify the individual cylinder that is at fault. The injection line is removed for one cylinder at a time and the cap installed on the fuel rail in place of the injection line. When the cylinder with the offending injector is capped, the rail pressure will rise and the truck will start. In some cases it can be highly advantageous to have multiple caps, because several injectors that return slightly too much fuel can have the same effect as a single injector with extremely excessive return flow.

Injector block off tools can also be useful for diagnosing engine knocking sounds that may be attributable to an injector or a single cylinder problem particularly on engines where this capability is not available through the scan tool, or a bi-directional scan tool is not available.

When working on high pressure fuel systems, always educate yourself first by reading appropriate factory service information, use common sense, and, above all, WEAR SAFETY GOGGLES!