After I bought up my current common rail diesel (CRD) Nissan Patrol in 2008, one of the first modifications that I planned was the installation of a diesel chip. Diesel chips are piggy back Electronic Control Units (ECU) that can be programmed to override some functions of the factory ECU and improve engine power, torque and fuel economy. I’ve had experience with ECUs from my previous Di Patrols, which improved overall performance and fuel economy to some degree, so there was no reason why the same would not apply to the new CRD. The Di Patrol ECU only altered fuel delivery, so they weren’t overly sophisticated and sometimes introduced their own problems, and the CRD diesel ECUs were no different, as they too only adjusted fuel delivery. But then a new ECU came out offering much more and I was asked to do a test and review, which was something that I couldn’t refuse.