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1994 PCM EFI 351 starting problems

L

lpjjrose

New member
I am having an issue when trying to start my boat at times. No fuel into the throttle body, and if I squirt a little gas in, it starts and runs fine. Any ideas?
 
If the throttle body is "dry", you have a fuel delivery issue....could be filters, fuel pump, electrical to the fuel pump, shutoff valve misadjusted, anti syphon valve malfunction, vent restriction, or damaged/restricted pickup tube.

I'd start with a pressure gauge and a voltmeter....and the service manual....
 
Thank you very much for your response. Fuel pressure to the throttle body is fine. Replaced both fuel pumps, checked electrical to the pump and cleaned pickup tube in tank and checked vent. No anti syphon valve. Sometimes starts just fine and if not I can squirt a little gas into throttle body and it starts and runs great. Just not always getting gas to the throttle body when starting. Not sure about the shutoff valve adjustment or throttle position sensor? Unfortunately I live a long way from a PCM service center
 
the TPS has nothing to do with the fuel pump system so you don't have to worry about that...the shutoff valve is usually a manual valve and is not likely based on your additional description...

after pondering it a bit, sounds like you have a dreaded intermittent....

The ECU should turn the pump on for two seconds, with the key ON and the engine OFF....and it should do this every time. I'd be inclined to change the fuel pump relay as they are known to cause issues...especially intermittents like this.
 
I am not sure where the relay is located, but will try and find it and replace. Any help in locating is appreciated.
Wouldn't that also cause a problem with intermittent cutting out while driving?
There is a small PC board mounted under the dash. Unfortunately Hydrodyne is very difficult to get info on, and am not sure how to replace. It seems to control (among other things I am sure) the beeper that comes on while the fule pumps are charging for the EFI. The beeper is now constantly on, and I have unplugged the wire to the beeper. Anyone that may know anything about the PC board please help...
 
I can also hear the pumps charging every time key is turned on, even when it will not start. It seems there must be something that causes a few bursts of fuel to be released when first cranking.
 
a bad relay could cause issues while running....depends upon the failure mode of the relay....most are relatively cheap so its not a bad idea to swap it.

The relay should be on the engine, near the controller....I'd suggest searching around and get a factory service manual...they aren't cheap but will pay dividends if you keep the boat any length of time.

Unfarmilar with the circuit board setup you describe...maybe check the hydrodyners forum...???
 
that is the typical form factor for a modern relay.....many times, you will see their schematic on the side (SPDT relay)....same parts used in the auto industry...
 
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