starting and power issues

[scottberry]

I have a 5.7 mercruiser that was recently rebuilt with some upgraded performance. It is a vortec motor with the TBI. It has been running good all summer but today it would not start. When my daughter tried to start, it gave a short grunt and then just turns over. I noticed that when I turn on the ignition switch, I do not hear the alarms or the fuel pump priming like I usually do. All the gauges and accesories seem to work properly but the alarms and fuel pump do not. I squirted a little ether into the tbi and it started right up but shut down as soon as the raw fuel burned off. I tested the fuel pump and it works fine. So now I am stumped.

Any suggestions on what to start with?

Thanks.

 

[maxxman04]

Re: starting and power issues

how did you test fuel pump? did you test fuel pump relay (if equipped)? check fuses?

 

[scottberry]

Re: starting and power issues

I unplugged the connector and put power and ground to the leads. The pump started working. It still wouldn't start with direct power connected to the pump.

Where would the relay be located.

 

[havasuboatman]

Re: starting and power issues

First, and this may sound stupid, but do you have gas in the boat?
That out of the way...
When you hooked power up to the pump, did you check to see if fuel was actually pumping? Just because the pump is making noise, doesn't mean it's working.

 

[maxxman04]

Re: starting and power issues

you need to start at the beginning. battery condition, battery cables. power to ignition switch, power coming out of ignition switch. power thru the kill switch. power thru the engine electrical connector. all wires and wire connectors good? all fuses good? most electrical problems are due to one wire messed up, or a bad fuse, something simple.

 

[scottberry]

Re: starting and power issues

I have been trying to isolate a little at a time. The batteries are new and fully charged. The ignition switch has power in the on and ignitoin phases. All of the gauges and trim work fine. I took the cables off and cleaned everything good and put back. I took the main harness plug and check connection, sprayed a little WD40 and put back togehter. Still nothing.
When I turn the key to th ON position, all gauges move, but I don't get the typical audible alarm and fule pump noise.
I am getting ready to check the oil pressure units as I heard that they are tied to the fule pump.

 

[maxxman04]

Re: starting and power issues

check all wiring at starter and starter slave solenoid too. and all grounds

 

[scottberry]

Re: starting and power issues

Thanks for all of the help. I found a schematic and totally forgot about the three fuses that are located inside the ECM box in the engine bay. It was the one little 10 amp fuse that blew. Everything is great now.

 

[scottberry]

Re: starting and power issues

The fuse blew again. Is this fuse tied to the fuel pump? Could it be tripping the fuse? I replaced it again and it worked fine the rest of the day.