2001 SAN GT40- Losing power randomly

[brock.higdon]

Alright. Went back to the lake. Replaced the tank pickup tube. Replaced the right angle piece that screws into tank. Checked the barbed fitting with the ball in it and it was working fine. Fuel pressure at 34 at speed when its running good. Drops to 19ish when it starts bogging.

One thing I thought about. The braided hose between the lp pump and the FCC has one spot where it is "crimped" and one where it is twisted, and at both spots it looks like it is collapsed. Im pretty sure its been like this since I bought the boat a few years ago, but I guess it could have gotten bad enough to choke the flow.

Going to order a replacement line for that and try pulling the low pressure pump apart to check for debris.

[kmarine]

I Know you replaced the low pressure pump over winter, but It sounds to me like you may have a bad one or water in your fuel. I Have replaced many of these. They tend to overheat and fail pre maturely. not only on PCM but merc and Volvo too.

[brock.higdon]

I Know you replaced the low pressure pump over winter, but It sounds to me like you may have a bad one or water in your fuel. I Have replaced many of these. They tend to overheat and fail pre maturely. not only on PCM but merc and Volvo too.

They are getting expensive, this will be #3 if that's it. I am going to run back to the lake in the morning and pull the LP pump off and check the screen for debris, then try running the boat on an external gas tank.

[kmarine]

For a GT40 as far as the oil pressure sending it into SLOW (limp) mode. The only wire which causes this is the #24 wire to the ecm. This wire is brown with a black stripe. the wire has two leads with a diode between the leads and a computer. One goes to a temp switch, the other to a oil pressure switch. The computer will let the boat fun below 2500 rpm normally. When the throttle is advanced past that the engine will pulse and change timing to avoid further engine damage. Did you try the remote tank recommendation. Just a quick note. If you have water in your fuel from phase seperation from ethanol in your fuel. it can trash a fuel pump in about a week. I have had to remove the fuel sending units and siphon with a copper tube to the bottom of the tank to suck out the water. It is generally below the fuel pickup. You may need to completely drain tank and start fresh. I recommend to pull the anti siphon valve and clean. moisture in fuel corrodes the spring and they stick.

[brock.higdon]

May be a stupid question, but- wouldn’t the fuel pressure on the rail stay the same if there was water in the fuel? Fuel pump can pump water just as hard as it can fuel, correct?

[kmarine]

Just a quick note the low pressure pump carter p4389 is $56;78 on amazon this pump is over $200 at skidim.com and other dealers. It pays to search part numbers online for pricing.

[kmarine]

Yes, but it will not run the engine with water. Did you try removing and replacing the wires connected to the map sensor? There is a hose also that runs from intake manifold to sensor. This triggers the injectors to fire. if you have fuel pressure. It is under the black cover on top of intake manifold. This part is a regular ford part on a crown vic or f250 puckup truck, so it is available at a auto parts store. there is a ford part number stamped into it. If you pull this hose off with engine running it will die. make sure you don't have a loose connection or leaking hose. There is also a white filter canister On that hose. on mine it is under the aluminium manifold.

[brock.higdon]

Made another trip to lake today. Replaced the check valve and the braided line between the low pressure pump and the FCC. And ITS FIXED!! 95% sure it was the braided fuel line.

[kmarine]

Glad to hear you got it going. Forgot that I replaced fuel line with my last low pressure pump. mine had a kink in it. I just had replaced the idle control motor in mine this weekend. Hope I am done repairing for a while.