Fuel Pressure dropping
 

Hello Everybody, I have an issue regarding fuel pressure. First off the engine specs. 99 502mag mpi .030 over to 509 with a Vortech supercharger and intercooler in a 27 fountain fever. the problem starts as soon as I push the throttle over 1600 rpm, the motor losses power lean pops and i have to pull back to idle. The boat starts perfectly and idles like a champ! I have fresh gas and have changed the fuel water seperator, the anti siphon valve has been removed and replaced with a ball valve so that is not the problem. I have changed cap and rotor, sea water pump and all fluids," just throwing that out their." I have mid 30psi at idle but as soon as I push the throttle forward the pressure drops rapidly and starts the lean popping....I called Vortech and Bob the marine tech said that I need to adjust the fuel pressure regulator with the vacum hose off to 60 psi, then with it hooked up it should be 50-55. Will a factory cool fuel pump make that pressure? it has a supply low pressure pump to feed it. With no load on the motor it will rev just like it should, I'm concerned that I might have an injector hung but the oil doesn"t appear to be full of fuel or have a strong smell of fuel. Does anyone have any other places to start looking? It's almost July 4th and I haven't been able to get my new to me boat on plane!! Sooo frustrated Please help

Still no help
 

:whistle::helmet: anybody have any idea,

You have clearly described a lean out condition, however, the problems are to numerous to speculate. If you are using the cool fuel system; based on its' designed application should push 40-43 # off vac reference. You have to have volume at pressure to be successful.

If you have a low and high pressure pump I would check the low pressure booster pump to make sure it is energized and working. My boat did the exact same thing when I lost my boost pump.

You need to check your fuel pressure with a gauge to see where it's at. Buy one if you don't have one or know someone you can borrow it from, they are only $30-40 at Sears or Autozone.
If you can pinch or block off the return line from your regulator, you will be able to tell what the pressure can go to, but it should be able to go upto 60 or more, and you can do that idleing. If not, you may need to upgrade your fuel pump. Is that how vortech does their system? Procharger uses an aeromotive a1000 for there system.
Good luck

the merc cool fuel system is a POS, trash all of the merc stuff, run a aeromotive A1000 EFI pump, boost referenced adj regulator, with a return to the tank....a bit of work but with the blower and any lean out bad things are going to happen...I run all the same stuff with my procharged setup...

I run all that same stuff on my Whipple setup. I ran the stock stuff for a few years and then one of the fuel pumps went bad and leaned out (BAD things do happen). If I would have done the fuel system when I put the whipple on I probably wouldn't have had to rebuild the motor.

Ok so I finally fixed my problem, It was indeed the boost pump. It was running but must had been going weak. I changed it out with a little bigger pump with more flow and a larger fitting moved up to 5/8" instead of the 3/8" and it pulls hard and has plenty of available fuel at the correct pressure. Knot 4 me you when the prize for being correct!! Thanks OSO