kfitz911

I don't have a picture of the line to show you, but it is the small one connecting the two pick ups that feeds into the sump. At the point in the fuel line the technician tested the pressure was to spec. However, it is volume under load when the sump drained that was the issue since it was just spraying fuel in tank. Not all of it, just enough for the sump not stay full and starve the engine when it needed it most.

The split in the fuel line is exactly what happened with my garage queen X-50 a couple of months back and it took 7 weeks in the shop to reach that conclusion. Started with the obvious by having the dealer replace spark plugs, then it moved onto the fuel pressure regulator, checked fuel pressure (good), replaced fuel filter, drained and replaced the fuel, the two fuel tank pick-up lines replaced, inspected wastegates, all with no improvement. It fell on it's face under boost and massively stuttered, cutting out. But if you rolled into the throttle, keeping out of boost and not over .5 bar, it would pull evenly and smooth. No codes. After all that the mechanic suspected, perhaps, the MAF, so we consulted with Evoms since that is where the ECU tune was from along with their diverter valves and F pipe and they said the MAF failure is possible, but if replacing it we might as well go with the Hitachi conversion, intake kit, and their wastegates along with the corresponding ECU tune to get the most out of the car. Got all that installed and, unfortunately, no change. Finally, the mechanic decided to see if the fuel sump was staying full after a bit of acceleration by shutting the car off immediately while on an empty road near the shop and, sure enough, that was the issue. Took back to shop and pulled out the pickup lines/pump/etc... and the little U-shaped rubber hose at top had a 1 inch split in it. He replaced it and drove the car - it went like stink. Of course, with all the changes from Evoms we did he was over the top excited with how fast it had become, since it already pulled hard prior to this issue. Now it is an absolute beast and super fun to drive, spinning the tires in 3rd gear! Anyhow, long story made even longer but just wanted to share in case someone else's car starts stuttering under boost. Don't immediately think spark plugs/coil packs...