drunkstang

Hey guys.. new to boating world, but not new to engines and high performance things..... I have a 98 Baja boss 302, with 454 mpi fuel injected motors.
The port side gine is having issues with the fuel pressure.Once the engine is started is has around 50psi and then in a matter of 6 to 8 seconds it starts to jump up to 60 then 70 and to 90psi.. and stalls the engine. I have checked for a kinked return hose , just replaced the fuel pressure regulator in the box where the fuel pump is and still the same problem. All of the lines were also not clogged and I replaced the fuel filter...... I am stumped , any help would really be great... Is there a chance the other regulator by the back of the intake is bad??? I just thought the fuel pressure would have to be correct by the time it was there, due to no return line from the intake...
Any help would be great guys... Thanks

Vinny P

I am sure you checked it, but you didnt mention whether you checked the vaccum hose going to the regulator. I have seen them kink.

drunkstang

Thanks, but yes I have checked the vaccum line.... anyone else have this problem????

BUIZILLA

on the fuel cooler, under the regulator, is a small screen in the body, take it out, that restricts the return flow when it gets plugged and the fuel pressure escalates... pain in the a$$ to get to, but that will solve your issue.

Mats2

As said everything points to a restriction somewhere in the return from the fuel pressure regulator to the fuel filter. Screen, or fuel lines. I think the regulator is 40 psi with the vacuumhose disconnected on your engine.

Ted G

Did you replace the pressure regulator on the rail too?

drunkstang

No, I didnt replace the one on the fuel rail yet. They didnt have it in stock. I did take the entire fuel system off to replace the one in the box. I wish I would of knew there was a screen in there.. Where is it located????? I didnt remember seeing it under where the regulator went... Oh and yes it is a pain in the ass to get to!!!!!
Think I should try the one on the fuel rail before I go threw all that trouble of taking the box back out?????

Thanks for all the help guys.....

drunkstang

Oh ya, one more thing .... the return line was def. not clogged .. I had it completly of the boat.....
Should I try cleaning out the screen or take it out and not reinstall it??????

Mats2

The fuel pressure regulator on the rail is not used to regulate the pressure. So you can forget that one. It is somewhere in the return system, screen, line or connection to the water separating fuelfilter.

Apart from that the fuel pressure guage or sender may of course be faulty. You could perhaps double check with an external fuel pressure guage on the schraeder valve on the fuel rail. It should show 40 psi with the vacuum hose disconnected from the regulator. The pressure should be rock-steady no matter what you do all the way to WOT

drunkstang

OK, I have tried two different guages at the schader valve. So we can say the guage is good... I need a little more info on this screen in the fuel box.. Wether or not I have to clean it or just remove it..
I feel now after the info I am getting on here it could just be this screen. When I do a key on and off test the fuel pressure goes to 65-70 psi , but it bleeds off real quick to around 45psi. I am thinking with the engine running it will not keep up and return the fuel fast enough...
So thanks again, and just a little help on this screen and I will try this when the sun goes down a little. Its hot as hell here in NJ today.. Close to 98.....