I have an Accusump, which is a mechanism which acts as a reserve supply of oil, if pressure should drop too far, at the end of a hose, connected to the rear of one of the engine's galleries. It is connected by way of a Peterson adjustable remote pressure relief valve. The hose is on one side of the in/out ports. It typically reads 35-45 PSI regardless of how I adjust the bypass valve. It hardly moves regardless of higher oil pressure elsewhere. In the previous engine, I had the Accusump T'd into a circuit that went from the oil pump to an external filter and oil cooler and back. Then, its gauge was responsive to the pressure as it fluctuated due to RPM or heat. Is it reading wacky due to the bypass in the Peterson valve which is in-between it and the inlet? In the Peterson unit is a straight-through passage with the bypass port T'ing off it in the middle. When the pressure overrides the bypass valve, oil goes into the crankcase (or vents to atmospheric pressure) through a -10 hose (same as the other to the Accusump). When I put a gauge at the other end of the oil gallery (that the relief valve is on) near the pump, I found I had adjusted the bypass valve up to 210 PSI! I am wondering if the pressures in gallery passages near the pressure relief valve are being adversely affected by all the oil that is flowing out. This point is at the rear of the main gallery. Am I upsetting the pressure balance designed into the engine? This is a Subaru boxer style, four cylinder, EJ 257 motor. I have the stock internal oil relief valve disabled in this 12mm, high capacity pump. I am wondering how I should best have the Accusump plumbed in. I have various gallery plugs to choose from.