5.7L with no ignition. Dead as a door nail.

[Peter16]

My friend recently imported from the states a 5.7L EFI (not MPI) mercruiser (bravo 2) on some large bayliner. Couldnt be more then 6 years old.

He could not start it because it was full full of water so another man pulled it apart and sent the heads away.
I was given the task of reassembling the motor from just boxes of parts.
Fast forward to today where i was at the stage of running the motor. I turn the key onto ignition where you would normally hear the fuel pump sound and the low oil pressure buzzer usually sounds. I heard nothing. Dead quiet. The motor turned over okay but no spark was observed. I am not getting any voltage at the coil either. When i put my little jumper leads onto either side of the coil it would appear i have a dead short.

2 things i have found odd during reassembly was the colour of the wires going to the coil, usually purple and grey. This motor has red and white. Also the white/red and white/green wires from the dizzy do not have any matching wires from the harness, I only found 2 spare bullet connectors which seemed to be in the correct location. They are orange with a white stripe and i think brown. (dont quote me they are very faded) I am confident despite being odd colours they are hooked up correctly. There are no other spare wires to be found anywhere.

I have heard when you pull out the harness plug you can join pins 1 and 5 which should start the motor. I tried this and still nothing happened.

So any ideas as to what i have missed? it has to be something simple because we had ignition before the motor was taken apart.

all suggestions greatly appreciated.
Peter

 

[Another retired guy]

Re: 5.7L with no ignition. Dead as a door nail.

Can you clarify something for us - you say at the start of your post that the boat was full of water? and that the engine couldn't be started. Then later on you say that you had ignition prior to the rebuild?
Were the engine electronics under water? At what point in the sequence was there ignition?

 

[ENSIGN]

Re: 5.7L with no ignition. Dead as a door nail.

With the key turned on make sure you have 12 volts on the purple wire at the engine side of the harness connector.If you do try disconnecting the wires going to the shift interupt switch.

 

[300sflyer]

Re: 5.7L with no ignition. Dead as a door nail.

It sounds to me like you need to determine the exact year of the engine, and locate a Merc service manual to properly trouble shoot these electrical issues. It could be as simple as a bad ignition coil, or it could be the wiring has shorted out some where, but impossible to say for sure. If you can tell us what year the engine is, [or post the serial #] someone else will likely chime in with a link to the service manual.

 

[300sflyer]

Re: 5.7L with no ignition. Dead as a door nail.

With the key turned on make sure you have 12 volts on the purple wire at the engine side of the harness connector.If you do try disconnecting the wires going to the shift interupt switch.

With a Bravo drive, he will not have a shift interupter switch.

 

[cyclops2]

Re: 5.7L with no ignition. Dead as a door nail.

If it filled with salt water ????? Or even a long time in fresh water.

I would back out of the job. Corrosion of every electrical switch, sensor, relay, trim tab controls, wires. The list is endless.

I never start those jobs because you can never stop trouble shooting & running up a large endless bill.

 

[Peter16]

Re: 5.7L with no ignition. Dead as a door nail.

my apologies. Only the motor took a dose of water. it wasnt filled, just milky oil and a little rust on the plugs. With a few compressions being uneven
possibly during transport. i have also checked the fuse on the starter motor it is okay. i have 12 volts at the circuit breaker. And the 3 blade fuses next to the ecu are also intact.

EDIT- gauges do turn on when the key is onto ignition. no taco when cranking the motor though.

 

[Don S]

Re: 5.7L with no ignition. Dead as a door nail.

What's the engine serial number? Can't look at wiring diagrams if we don't know exactly what you have.

My friend recently imported from the states a 5.7L EFI (not MPI) mercruiser (bravo 2) on some large bayliner. Couldnt be more then 6 years old.

Every EFI engine since 2001 is MPI from Mercruiser.

 

[Peter16]

Re: 5.7L with no ignition. Dead as a door nail.

It must be older then. 0L607988

 

[Don S]

Re: 5.7L with no ignition. Dead as a door nail.

You have a 2000 model engine there, 12 years old, not 6.

On the engine, you should have a fuel pump relay, and an ignition relay that you need to check. Since this was a rebuild from a box of parts, I would make sure all those ground wires on the engine are hooked up correctly. Without those grounds, the relays will not activate. There is also a main ground wire on the ECM Harness that must be hooked up.

View attachment TBI Wiring.pdf

 

[cyclops2]

Re: 5.7L with no ignition. Dead as a door nail.

My 2002 5.0 L had developed a intermittant no run problem. It was 1 of those split pins in the large plug & socket at the back of the engine. Racing mechanic said that before we went to the boat.
Cure was his CAREFULLY spreading any pins that looked slightly closed up.............Use extreme care on the male split pins.

MOST IMPORTANT ......Disconnect 1 of the battery post cables COMPLETLY. A short at the pins could really screw you up badly.