Hello everyone,
I have been having some intermittent limp mode issues on my supercharged z4m when going wide open throttle at high rpms. After checking fault codes, nothing was apparently wrong but I suspected the car to be under fueled.
I did assume it could be the throttle body linkage impacting and causing issue, but there isn't any issues there.
Well my fuel pump died and I replaced it with a larger aftermarket component to aid in fuel supply and solve the under fueling issue. After installing, filling the tank with fresh gas, and charging the battery, the car won't start. I posted a video to show what it does. I pulled the plugs and they were wet and dark (only after 500 miles). The car is running very rich but that shouldn't effect starting. I cleaned the plugs well and then recorded the video below. Fuel pressure is existent, but I didn't put a gauge on it.
Now a few thoughts I have. I'm running a vf570 but without a tune from vf. I run a ttfs tune. I was told by vf that the car should be tuned for 3.5bar fuel pressure vs what I guess is 5bar oem. From what I understand the tuners do this to get more flow from the oem pumps as they are more efficient at lower pressures. I am using the oem 5 bar regulator still but flowing roughly 2x more thanks to the bigger pump. I have a 3.5bar regulator sitting around, but decided to keep the 5 bar as I didn't need even higher flow. However.. my car is still tuned for it. With that being said, this shouldn't effect starting of the car... or atleast I wouldn't think.
Any thoughts? Thanks!
Note- I have asked a lot of E46 friends. This appears to be one of the rare times our powertrain differs from the m3. The fuel system is very different on our cars.
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