Fuel pressure?
 

I have a MPI 502 with an intercooled M3 Procharger. It was cutting out at full throttle so after checking the timing I started to play with the fuel pressure. It would not go over 4,000RPM. For some reason, it started running much better with less fuel pressure but it still isn't running the way that it should, though it will now run at 4,400 RPM...I think that the pressure is as low as I can go without being too lean. Is there a reason why it would not want to burn more fuel? And yes, they are 1/2" fuel lines. There has also been some white smoke while the boat is coming up to plain. Could this be related to engine temperature? The water temp guage does not move while out on the lake. Is it possible that it is not getting enough air? The air cleaner should be plenty large and it appears to be clean enough... I also checked for codes and none came up. Has anyone had any similar experiences or does anyone have any recommendations?
Thanks

Are you sure the white smoke you are seeing isn'g just steam from the cold water hitting the hot exhuast?

That is a possibility...
The manifolds definately get warm but they don't get so hot that I cannot hold my hand on them.

Depending on the lake water temp, it may steam this time of year yet.........

Check the tension on the procharger belt. Also if you are not running a thermostat it will not move the needle on the gauge very mcuh.

Change fuel filter. I know you said you have 1/2" fuel lines but check them anyways, mine was doing this sunday and my fuel line was collapsing where it feeds the high pressure pump

I changed the fuel filter and tightened the belt on the supercharger. I also cannot find any kinked or otherwise restricted fuel lines. Tomorrow I am going to install new spark plugs and get a new belt for the supercharger...I hope it works.

Are you running a MSD or similar ignition? What is the spark plug gap? Is 4000 rpm about 3/4 throttle? When I first got my boat with a Procharger had stock ignition and bad spark plug gap of .045. Engine pratically cut off above 3/4 throttle. With increased internal cylinder pressure spark canot jump gap. I reduce gap to .030. Made big difference, then put on MSD and put gap back at .045

I would be very careful backing the fuel pressure all the way down without knowing how the motor is burning. Motors usually run great when lean right before they melt a piston.

Fixx
 

do you have a boost referenced fuel pressure regulator??
also +1 for the spark plug gap..you said efi,did you get your mefi tuned for the pro charger?

I have the stock ignition and the computer has not been reprogrammed. When I put the new plugs in I gapped them to .030. Yes, I have a boost referenced fuel pressure regulator. Has anyone had problems with their regulators?

The other day, I did happen to check the intercooler. It was leaking. When I pulled it off, there was about 5 oz. of water inside of it. I also pressure tested it to confirm that the core leaked and it failed. I replaced the intercooler and it did not fix the problem, but I can feel the difference up to 4,000 RPM.

This weekend I will do a compression test.

Procharger regulator is junk. I have one just reconditioned from Bell Engineering, if you're interested. click here

Upgraded my ECM and don't use it anymore.

Thats how i lost my engine. Busted intercoller = hydrolocked and bent rod, crush piston. In the drive way on hose!

Agreed. I replaced my boost reference regulator and the fuel pump.

I didn't find anything when I did the compression test. Everything looked good there. My next step will be to replace cap and wires and MAP sensor. I will check out the fuel pump next time I go to the lake...

Was it running good and then started to have the problem, or was this just worked on, assembled/reassembled or anything like that?
The reason I ask is, are we trying to trouble shoot a newly developed problem, or newly install problem.

I helped a friend install a Procharger on a 454MPI and we started it on the hose in the shop, sounded good and idled perfect. Towed it to the lake and it didn't sound right. Ran it up and didn't have as much power as it should and couldn't get it over about 4000. Scratched our heads for about 45 minutes at the dock looking for anything strange and checking timing. Reach under plenum to check for loose hoses and pulled out an injector plug. It must have not been locked on all the way, and popped off while towing. We hauled it back to the shop and pulled the plenum, reconnected the injector plug, and put the plenum back on. Dropped it in and ran like a raped ape, compaired to before.
Not that this is your problem, but 1 dead cylinder can cause your problem.

This is a newly developed problem. It didn't do it before...

I changed the distributor cap, rotor and plug wires and it runs better but it did not solve the problem. The cap and rotor probably looked worse than I have ever seen any before but it was the first time that I have changed them since I have owned the boat. I am starting to think that I might need to get an MSD ignition on this thing...

whats your fuel pressure at? and have you checked your injectors for crap in the tops of them. had the same problem with mine read the post on here about mpi owner fyi.

After replacing the TPS, MAP and IAT sensors, the boat has run much better. It no longer cuts out at 4,000 RPM! I appreciate everyones input on this issue.