Have 04' Cobra with pully changed 12-14lbs w/boost bypass has been running this way now for 2 years. Last weekend while running a moded GT the supercharger wont build over 6lbs and if it does the boost gauge crazey... Any help... Thanks...
Run hard? How so? Like ran it at high speed (150+) for and extended period of time? Or... I was redlining the piss out of it and may have bumped the rev limiter once or twice?
How is the car tuned? Chipped or flashed ECU? Do you have a handheld tuner so you can scan for codes?
First thing I would check is the FRPS. See pic below if you are unfamiliar with this part and/or it's location. Pull the vacuum line off of it and check for fuel. If there is fuel present in the vacuum line then you most definitely have blown the diaphragm in the FRPS. Unfortunately not all blown FRPS's exhibit this symptom.
You can pick one up at your Ford parts counter for about $62.
Your FRPS could still be the problem. They are a high failure item on high boost Cobra's so you might as well pick one up and see if it corrects the condition. Also, pull your engine oil dipstick and smell it. Does it smell strongly of gasoline?
In the future when you get the chance reconnect the factory boost bypass and have your tuner disable it in the ECU. It's the safer and more approved of method.
Changed the FRPS it seamed to work until later last night... it is more of an intermitent problem now , where as before it was every time the boost went above 6...