View Full Version : Intermittent fuel pump- 97 ps205/ LT-1

07-01-2010, 06:29 PM
Hi, Curt here. Long time lurker, first time poster.

I'm hoping there is someone that is a little savvy on the LT-1 fuel system here.

'97 ProStar205/ LT-1 combo. Great boat. Well.....usually anyway.

I'm intermittently dropping power to the fuel circuit in the boat. Starts easy, I can idle/ putt around no problem. As soon as I roll it on, it dies. I know, fuel filter....not it. I replaced the main filter aready and I can watch the flow through the secondary filter.

The entire fuel power circuit just goes away.

The quirky part is that it takes about a half hour before it will start again. When enough time has passed, it fires up like an anxious puppy.

In the meantime...
A) no pressure at the fuel rail.
B) no power at the pump fuse.
C) no power at the fuel relay.
D) no power to the ECM fuse.
E) no power at the ECM relay.

That is taking readings directly from the wire to a bare metal on the block AND the same results directly from the battery neg.

It's like there is a master control circuit that goes into distress mode.
It just shuts the ECM and fuel circuits off.

When it is done with it's hissy-fit, all functions return to normal and it fires right up.

It's not overheating, just the opposite. It's under temp. I have a new block thermostat coming, the mixing t-stat is fine.....the boat is running in the 140's. I replaced the ECT sensor, but the old one checked out fine.

I can only find two main grounding points on the engine, both check out clean. fully charged battery. 13.8v no-load, 12.2v starting.

Lanyard is fine, power at the ignition switch checks out.

Main circuit breaker shows power on both sides.

I don't have decent schematic to work with. sent an email to MasterCraft about getting one, haven't heard back yet.
In the meantime July Fourth is looming large and I am getting a little worried.

Any ideas?