377 Mag Bravo 3 DTS Re-Power electrical problems

[johnsonla]

I purchased a 2009 377 Mag MPI Bravo with DTS. Engine Serial number 1A344800. Trying to figure out if the PCM is shot.

I called Mercruiser tech line, gave them my engine serial number and they gave me the part numbers to purchase the correct Smartcraft harnessing kit to rig my boat with.

After installing the new rigging, I took the boat in to a certified Mercruiser dealer to get them to program the new Smartcraft / DTS harness. They were unable to complete the set up and could not get the engine to start.

Brought the boat back home and found that the only way the engine will start after powering the key to the on position is to remove the start relay and jumper between the red and the yellow/red stripe wire momentarily to crank the engine. This starts the engine and it will run until the key is turned off.
I have swapped out the relay to make sure it was ok. I have verified that the shift position switch is working.

It would seem that the PCM is not sending a start signal to the start relay when the key is put in to the start position but I can not figure out why.



I'm stumped.

Anyone have any idea's?

 

[achris]

Neutral safety switch?

 

[johnsonla]

Yes, checked and verified that it is working correctly. I've seen it referred to as shift position switch and neutral safety switch.

 

[achris]

I'm referring to the switch inside the shift control box, at the helm, not the shift position indicator on the engine (next to the shift motor on the starboard rocker cover)...

Edit: Can't remember if DTS actually has a neutral safety switch in the control box, now that I think about it.

 

[johnsonla]

I would say it's not a problem, part of my trouble shooting was to unplug the complete smart craft dts harness from the 14 pin connector at the engine. I plugged in a mercruiser adapter dts to non dts harness then plugged in a non dts test console. Same result, engine would not start with the key but powers up in the on position. (fuel pump pumps up etc.) As soon as I jumper the start solenoid the engine starts and runs and will shut off with the key.

 

[achris]

Check you have power coming in on the START wire from the key (when the key is in the START position)... It'll be yellow/red...

 

[Bt Doctur]

Relay/solenoid same operation .If you have 12v in the start position at the key on the yellow/red wire and you can identify the yellow/red coil wire at the slave ,put a jumper in and test it.

 

[kenny nunez]

The starter boost/assist relay is on top of the manifold behind the throttle housing. That is where it is on my 6.2 MPI.