High Pressure Fuel Pump

[jhersey29]

Does the high pressure fuel pump inside the FCC have a check valve? I am trying to diagnose the cause of fuel pressure not holding at the rail when the key is off.

1.) Leak in lines
2.) Regulator diaphragm bad
3.) Stuck open injector (any easy one to tell which injector?)
4.) Check valve in FCC or FCC High Pressure Fuel pump stuck open

Thanks

[mnwakerider]

What are your symptoms? Do you have any pressure at the fuel rails or on the shrader valve on the top of the FCC?

Just pulled apart my entire FCC and Low Pressure pump system. I thought I had a bad HP Pump, but it was the LP pump. LP pump was still running but was bad and wouldnt pull from the tank. The only check valve I found in my 2003 SAN was just off the 90 degree fitting off the tank. Otherwise I didnt see a single check valve from LP Pump to FCC and FCC to fuel rail.

[scottb7]

How many hours were on your boat when the lp pump went out? I am kind of curious. I decided to replace both high and low pressure pumps on my boat this fall at about 900 hours.

[mnwakerider]

I have around 1100 Hours on my 03. Figured it was about time for it to go. Never run the boat below 1/4 tank of gas, but it was a relatively easy fix for $135.

How many hours were on your boat when the lp pump went out? I am kind of curious. I decided to replace both high and low pressure pumps on my boat this fall at about 900 hours.

[jhersey29]

Mine runs fine. 1006 hours. Replaced low pressure pump earlier this year in preemptive strike to keep skiing everyday. My only issue is I can not get it to hold psi at the rail. Key on goes to 40 but drops very quickly as in instantly to zero. Starts and runs fine but it should hold pressure at the rail or I believe it should. Gt40 EFI multiport. Does seem to have a slow start from time to time. It always starting now after a distributor replacement and runs good. I'm trying to understand where the heck the pressure is going. All my car mechanic buddies say it is usually a check valve in the fuel pump. Unfortunately none of them are experienced with FCC setup. Cars hold pressure at the rail and don't instantly drop like this.
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[mnwakerider]

Hmmm... Beyond my area of expertise. I dont have a pressure gauge (burrowed a buddies to trouble shoot my system) so I cant help with what my system does after initial prime. Good luck.

[jhersey29]

Replaced high pressure pump and now it holds 40 on the rail. So the answer is yes, there is a check valve in those pumps.
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[jhersey29]

Oh and I did break 3 oil pressure wrenches taking the canister off the FCC head. Finally got it with 2 good USA made ones from Carquest. I wont ever put thread sealer on that again. Only going to use anti-seize.
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