What’s going on people I haven’t been on this page in years I just recently picked up 5 f4i’s cheap and I love the tanks anywho. 1 of them is giving me hell I have spark ecu work no tip sensor kickstand or anything to stop it from starting fuel pump primes and feeds to fuel line. I put about 24 ounces of gasoline in the tank so I can try to start the bike it turns over and wants to start but acts like it’s not getting fuel. I swapped injectors with another set and fpr as well. I also checked to see if my spark plugs were getting current and they were well for the last time before I left the shop I figured let me give it one last try well the bike started but threw out all the gasoline put in through the exhaust I’ve never seen anything like it. Anyone else ever deal with something similar??

 

Depending on how much you cranked it during the no start scenario, it's entirely possible you filled the header pipes with fuel. I've seen carbureted vehicles do this. Back in college a guy cranked on his Camaro for several minutes before realizing he had his distributor in backwards. He had filled the entire exhaust system with fuel, and when the car finally fired, the muffler exploded. It literally shook all the dust off the ceiling I beams.

 

I get that but why would it get fuel into the headers while I’m trying to start it but not get the fuel needed at the beginning to start it on its own if it’s already getting spark

 

Since your exhaust was full it sounds to me like you were definitely getting fuel. Maybe too much... perhaps the injectors you swapped in are better, maybe there was no spark until you fiddled with it. Anyone with better fuel injection knowledge care to weigh in?

 

You didn't fill the exhaust from cranking thats not really possible. Most likely the fuel pressure regulator is bad and allowing mass amounts of fuel into the engine.