fuel pressure Question???
07-17-2012, 06:08 PM
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fuel pressure Question???
I have a 97 Baja 272 With a 502Mag MPI Cool fuel SN# starts with OK17......dont know the rest sry.
Anyways i have been having some issues with it not running right latly. For the first 5 minutes or so it runs great. Then it loses all mid to high RPM Power and takes forever to get on plane from a standstill. Seems to idle fine and rev fine in neutral.
I have checked all the plugs they look good to me but I am no expert. The distributor cap had some corrosion on the inside of it so I replaced it and the rotor. I put new wires on because a few looked cracked and like they have never been changed before...the boat is 15yrs old.
i just checked my fuel pressure here is what i saw.
Just turning the key on, not starting= 28psi which drop'd with in a second to 20psi. It held @ 20psi for a few minutes then slowly droped to 15psi where it held.
Running at idel= 25-27psi
Running at idel with vaccume hose off of the pressure reg 30-32psi.......note: I am assuming that the circle thing on the front of the fuel rail right by the shrader valve is the fuel reg.
Running at 3k RPM= 20-22psi
My question is this. Is the Fuel Pump bad or the pressure regulator or both. Anyone know for sure?
Edit: or could i have a restriction somewhere in the fuel line?
Any help you guys can offer would be most appreciated.
Anyways i have been having some issues with it not running right latly. For the first 5 minutes or so it runs great. Then it loses all mid to high RPM Power and takes forever to get on plane from a standstill. Seems to idle fine and rev fine in neutral.
I have checked all the plugs they look good to me but I am no expert. The distributor cap had some corrosion on the inside of it so I replaced it and the rotor. I put new wires on because a few looked cracked and like they have never been changed before...the boat is 15yrs old.
i just checked my fuel pressure here is what i saw.
Just turning the key on, not starting= 28psi which drop'd with in a second to 20psi. It held @ 20psi for a few minutes then slowly droped to 15psi where it held.
Running at idel= 25-27psi
Running at idel with vaccume hose off of the pressure reg 30-32psi.......note: I am assuming that the circle thing on the front of the fuel rail right by the shrader valve is the fuel reg.
Running at 3k RPM= 20-22psi
My question is this. Is the Fuel Pump bad or the pressure regulator or both. Anyone know for sure?
Edit: or could i have a restriction somewhere in the fuel line?
Any help you guys can offer would be most appreciated.
Last edited by tlracer1; 07-17-2012 at 06:14 PM.
07-17-2012, 06:16 PM
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fixx
I have a 97 Baja 272 With a 502Mag MPI Cool fuel SN# starts with OK17......dont know the rest sry.
Anyways i have been having some issues with it not running right latly. For the first 5 minutes or so it runs great. Then it loses all mid to high RPM Power and takes forever to get on plane from a standstill. Seems to idle fine and rev fine in neutral.
I have checked all the plugs they look good to me but I am no expert. The distributor cap had some corrosion on the inside of it so I replaced it and the rotor. I put new wires on because a few looked cracked and like they have never been changed before...the boat is 15yrs old.
i just checked my fuel pressure here is what i saw.
Just turning the key on, not starting= 28psi which drop'd with in a second to 20psi. It held @ 20psi for a few minutes then slowly droped to 15psi where it held.
Running at idel= 25-27psi
Running at idel with vaccume hose off of the pressure reg 30-32psi.......note: I am assuming that the circle thing on the front of the fuel rail right by the shrader valve is the fuel reg.
Running at 3k RPM= 20-22psi
My question is this. Is the Fuel Pump bad or the pressure regulator or both. Anyone know for sure?
Any help you guys can offer would be most appreciated.
Anyways i have been having some issues with it not running right latly. For the first 5 minutes or so it runs great. Then it loses all mid to high RPM Power and takes forever to get on plane from a standstill. Seems to idle fine and rev fine in neutral.
I have checked all the plugs they look good to me but I am no expert. The distributor cap had some corrosion on the inside of it so I replaced it and the rotor. I put new wires on because a few looked cracked and like they have never been changed before...the boat is 15yrs old.
i just checked my fuel pressure here is what i saw.
Just turning the key on, not starting= 28psi which drop'd with in a second to 20psi. It held @ 20psi for a few minutes then slowly droped to 15psi where it held.
Running at idel= 25-27psi
Running at idel with vaccume hose off of the pressure reg 30-32psi.......note: I am assuming that the circle thing on the front of the fuel rail right by the shrader valve is the fuel reg.
Running at 3k RPM= 20-22psi
My question is this. Is the Fuel Pump bad or the pressure regulator or both. Anyone know for sure?
Any help you guys can offer would be most appreciated.
07-17-2012, 06:25 PM
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Not sure what you mean by boost pump??? Are you referring to the fuel pump or is there a secondary pump that I'm unaware of??
07-17-2012, 11:11 PM
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Fuel pressure is definately low. It should be around 40psi.
I would bet its the fuel pump going out, but it could be the regulator or an obstruction in the line. The only way to know for sure is to take fuel pressure readings at other spots.
I would bet its the fuel pump going out, but it could be the regulator or an obstruction in the line. The only way to know for sure is to take fuel pressure readings at other spots.
07-18-2012, 12:25 PM
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Are there more shrader valves in the fuel system somewhere?
What other places would you mean?
PS. Griff i see you're from Omaha.. you boat on the river much?
07-19-2012, 01:24 AM
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No more valves that I'm aware of. You would have to get a brass fitting and T into the line at other locations. Most likely its the pump though.
I used to boat the river quite a bit, probably 10-15 times a year, but have not been on it since Summer 2010. I boated out of Bellevue mainly and then Sandpiper for year when Bellevue was flooded. I just used the ramps and trailered. I left the boat at LOTO all last Summer and part of this Summer already. Its home now, so I might hit the river the next 2 weekends. Then it goes back to LOTO until at least after the Shootout.
I used to boat the river quite a bit, probably 10-15 times a year, but have not been on it since Summer 2010. I boated out of Bellevue mainly and then Sandpiper for year when Bellevue was flooded. I just used the ramps and trailered. I left the boat at LOTO all last Summer and part of this Summer already. Its home now, so I might hit the river the next 2 weekends. Then it goes back to LOTO until at least after the Shootout.
