ECM failure ?

[beerhunter]

I have learned a lot from you guys just by reading old posts. I am not a mechanic by trade. I have never even looked under the hood of a Yamaha before. I just kind of want to hear what you think. I bought boat with a 2000 150 HP Yamaha HPDI engine that had not ran for several years, I was told the engine went under in fresh water at the dock, I was told they got all the water out and managed only to get it to run on starter fluid. It would not stay running. All of that appears to be true. It has a good spark, fires right up if I squirt a little starter fluid in one of the spark plug holes. Then it stalls in about 2 seconds. It has good compression. I bought the YDS software and service manual. The motor has 209 hours on it. I am attempting to run the motor on gas from a 1 gallon can because who knows what's in the tank. So, using the YDS software I was able to enable the oil pump for 5 seconds located on the port side of the motor. I could hear it make a slight pulse noise. Then using the YDS software I enabled the electronic fuel pump inside the vapor separator. I hear nothing. So I jumpered in the 12 volts directly to the fuel pump. Nothing. With a ohm meter the pump looked like a open circuit. I opened up the vapor separator and removed the pump. After banging the pump against the vise several times it started to run when I applied voltage directly to the pump. I cleaned the pump up and left it running for a few hours pumping kerosene. the pump started running quiet and smooth so I decided to use it. The vapor separator had debris and sticky stuff inside of it. I cleaned everything up and reassembled it. Unfortunately the wires that run to the fuel pump were not supplying the power when I enabled the pump using the YDS software. The Red/Yellow wire which is positive was working fine. The Blue wire was not providing a ground. The Schematic indicates the Blue wire comes from the ECM wires 15 and 16 on the port connector. I rang the blue wires, 15, and 16 are tied together at the output of the ECM. Probably so the little pins on the ECM don't carry all the current on one pin. 15, and 16 ring to the blue terminal on the fuel pump. So it sound to me like the ECM is no longer sinking the current it needs to at pins 15, and 16. I have read that the Yamaha ECMs DON'T FAIL. I have also read many people suspecting a bad ECM and then it turns out to be something else. I plan to jumper in the ground path to the fuel pump and see if she fires up for real shortly. So is the ECM bad? Can you think of anything I missed?

 

[99yam40]

HPDI motor have a high pressure pump that run off of a belt. It has screens as do the injectors that will plug up. there are other filters in the system.

the medium pump in the VST supplies enough pressure to fire up, but not enough pressure to do much else.

a motor that went under and set up for a long time may have problems with internal rust on very important pieces like crank journals and bearings. good luck with the motor

 

[beerhunter]

Yes rust I can't see is a big worry. It would be awful hard to dry things out without getting the motor running for a while. I will need the Luck.