@Roger Boyle I am not the best on these systems but if you look at the two pictures this is the main difference I know about. Here is a brief description obviously rewritten by ChatGPT to help make sense of my waffle. On common-rail diesels, rail pressure is mainly controlled in two different ways, and some systems actually use a combination of both. 1. Inlet-metered / quantity-controlled system Here the control valve is on the low-pressure/inlet side of the high-pressure pump. You’ll see names such as SCV (Suction Control Valve), IMV (Inlet Metering Valve), fuel metering valve or quantity control valve. The basic flow is: Tank → low-pressure supply → metering valve → HP pump → rail → injectors The ECU effectively says: “I only need this much high-pressure fuel, so only allow this much fuel into the pumping chambers.” If the rail pressure is too low, the ECU commands the metering system to increase pump delivery. If rail pressure is too high, it reduces the quantity entering the high-pressure pumping elements. This is generally more efficient because the pump isn’t continually compressing a large excess quantity of fuel just to dump it again. 2. Outlet/rail pressure-regulated system The other arrangement allows the high-pressure pump to produce more fuel flow than the engine actually requires, and rail pressure is controlled by allowing excess high-pressure fuel to escape through a pressure control/regulating valve. Conceptually: Tank → HP pump → rail → injectors ↓ pressure control valve → return So instead of controlling primarily how much fuel gets compressed, you’re controlling how much of the compressed fuel is allowed to remain in the high-pressure circuit. If rail pressure rises above the ECU’s target, the regulator opens further and releases more fuel to the return side. If pressure is too low, it restricts that escape path.

Sounds either sortware related or someone changed the housing??

@Shah Islam glad you enjoyed the video, yes everyone is getting the load cages over the next few weeks, just need to get postage sorted out but im looking into that this week, will be asking for address over the next few weeks