March 2021

MARCH 2021 AFTERMARKET 23 speed and is accompanied by a more prominent click from the exposed port injectors. The engine now recovers its combustion composure, with the useful visual evidence, high pressure increases to 90bar. The reason for this is to prepare the high-pressure system in readiness for any instant high load demand. Keep this information in your pocket until later. Assessment With all this information available, what is my assessment? It is a fact that the only route for fuel to enter the engine combustion chamber is via the lateral feed injectors. The only explanation for incorrect fuelling quantity is a control deviation due to a circuit fault, physical hydraulic- mechanical injector fault, or a PCM calculation error. Having previously expressed confidence in the hydraulic- mechanical injector function focus transfers towards the PCM fuelling feed back system, the Lambda sensors should theoretically provide all the critical answers we need. Just to fill in a few gaps before you all go dashing to the internet blog sites, we did conduct exactly accurate injector current profile analysis. The ultimate PCM injector control is fuel pulse time and current path. Using Pico scope and a Hall Effect current clamp, we monitored the injector function together with high rail pressure. We noted no discernible change in injector control when witnessing a rail pressure drop. Please refer to Fig.5 for this. Blue/black trace represents the injector current path across two injector circuits, with both homogenous and stratified events visible. Green trace represents the PWM control for the high-pressure actuator. We continued monitoring current and rail pressure until the moment port injection took over. Looking to Fig.6, blue/ black trace in this instance represents the current path to the direct injectors, while the red trace shows the seamless transition to the port injectors. Coming up Keeping up so far? Well, it’s not over yet. Part three will discuss the response of Bank1 Sensor1 function and response. This will be conducted through direct current measurement, with Pico and serial data via VCDS, paying particular attention to fuelling correction. Now things are going to get very interesting. What you are expecting is not going to happen. Exciting isn’t it? Good enough for a direct-to-Netflix action movie, or even a mini- series? See you next month. e p tiv omo ut A subishi El Mit enuin 100% g s art tric ec e er high s renowned, nufactur s. n your area or t or which Mit t ed and manuf rmance Without Compromise ed, engineer actured to the s andards f subishi Electric i ing the expec ations of car and truck ma ur website to find Approved Distribut s i act us for more information. Mitsubishi Electric parts available for the Independent Aftermarket ont Perfo Design quality exceed Visit o or c www.aftermarket.mit subishielectric.eu Find an Approved Distributor and place an order by visiting: Fig 6