Help! Have been fighting a low fuel pressure issue for over a year. Original Issue: can come up to plane with 1-2 people in the boat, but as soon as put 6-8 or try to pull a tuber, cannot exceed 15 MPH. Additionally, burning thru SUBSTANTIALLY more gas than in the past. Began with all the basics (cap, rotor, plugs, wires, sea foam, etc). Did a rail test and only getting 22 PSI on the rail. Moved to fuel injectors (replaced one). After all else failed, installed a new fuel pump/cooler (OEM) and still only getting 22 PSI on the rail. Had mobile marine mechanic out multiple times in the fall and he replaced the Temp sensor. Fast forward to this spring and power issues and burning thru gas continues. Took into a local marine mechanic with a good reputation 2 weeks ago. Thus far they've replaced all the fuel lines, the fuel sending unit and another set of plugs, cap, rotor. Still only getting 22 PSI on the rail. Mechanic is asking for authorization to replace the fuel pump ($1,000). Given that I just replaced the fuel pump and the rail PSI stayed the exact same as under the old pump, I'm struggling to believe this is the correct fix (unless by some very odd chance I received a faulty fuel pump?). Any other thoughts as to what could be causing this low pressure issue? Thanks for any help you can offer.
-
Last edited by rphipps; 07-05-2016, 01:49 PM. -
Fuel pressure regulator?
Have you done a leak down test? Could be a stuck open injector.
Sent from my HTC 10 using Tapatalk -
Chris - just got off the phone w/Mercruiser and they suggested open injector as well. How do you perform a leak down test? BTW- just replaced the fuel pressure regulator on Saturday.Comment
-
Performed leak down test and is holding pressure at 22 PSI with key turned off. We replaced Temp Sensor previously and that did not resolve. Any other sensors on the rail that would cause low fuel pressure? I'm afraid at this point it could be the ECM?Last edited by rphipps; 07-05-2016, 04:15 PM.Comment
-
the fuel pressure is regulated purely by the pressure regulator, the pumps just keep pumping and the regulator lets it bypass back to the pump by relieving excess pressure.
you will need to test both pumps, the LP might not be working so the HP has nothing to pump.
easy test is to remove the hose between the LP and HP and see if you have good flow, don't do this for too long as running the HP dry isn't good for it, the only involvement the ECU has is to turn the relay on that drives the pumps.Last edited by ChrisSnow; 07-05-2016, 06:29 PM.Comment
-
Did you ever replace the regulator?Fixing everyone elses boat just so I can use mine...Comment
Comment