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ECU Housing Access

jokeenan7

Member
Messages
7
Reaction score
0
Points
20
Boat Make
Yamaha
Year
2005
Boat Model
SX
Boat Length
23
I cannot figure out how to open up the housing that contains the ECU. My injector on cylinder #3 STB engine is not clicking when I do the stationary test and I want to swap the ECU with the fully functioning Port ECU to see if it's the injector or the ECU. I've never opened these suckers and I can't find a video online of how to do it. There are four mounting bolts on the housing but they just spin, they aren't un-threading.

I know it's got to be something simple. What am I missing?
 
You have to take the tray out where the clean out plugs are and there is a nut you have to hold
 
It helps to have a second person, and wear long sleeves,as the rear hatch is unfinished and the fiberglass hurts like he!!
If you are single handed, you can use and rig the vise pliers to hold the nut on the outside/tray side and then fish the pliers out when they fall in.. It is painful to do alone. (I put it back in by myself and it was painful)

Another capable human will make the job easier. You only need them for only those 4 bolts. Open the rear hatch and look carefully and prepare, and you need the second person for maybe 20 minutes tops.
 
It may be easier to change the injectors from position/connector on one engine vs switching the ECU from one to the other. If you switch injectors and #3 still doesn't click you know the injectors are OK... Just a thought...
 
It may be easier to change the injectors from position/connector on one engine vs switching the ECU from one to the other. If you switch injectors and #3 still doesn't click you know the injectors are OK... Just a thought...
Yea, that's what I started doing. I took out the ribbons and unhooked the fuel rail, but there were still some brackets (one holding the throttle cable that I can't seem to remove) preventing me from removing and accessing the injectors. I couldn't find a video on that one either, so since I was flying blind, I thought the ECU switchout might be easier. It's turning out to be pretty labor intensive I have to agree.
 
You don't have to remove it all... I just did this a few weeks ago. For throttle cable undo the cable from the throttle and remove the 2 bolts outside the box surrounding the cable. Same for the fuel rail connection. I left some connectors that were hard to remove in place and just worked with it in place.

Always cover the air intake...if you drop something in there you are in big trouble. That's why there is that white cloth underneath mine while I worked.
 
Hopefully these help.
 

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Once you are there, you release the 3 Phillips screws holding the rail in place (Use a right-sized, high quality screw driver so you have the best chance of success) and you are then right there to swap the injectors. (Maybe there is a fourth bolt further back outside of the picture? I don't recall but it's a pretty obvious connection to the fuel rail)
 
Once you are there, you release the 3 Phillips screws holding the rail in place (Use a right-sized, high quality screw driver so you have the best chance of success) and you are then right there to swap the injectors. (Maybe there is a fourth bolt further back outside of the picture? I don't recall but it's a pretty obvious connection to the fuel rail)
Wow, great, thanks for the info.

So, the injector not "clicking", still doesn't tell me whether it's the injector or the ECU right? Could still be either?
 
90% is the ECU now. If you swap the connectors between 2 and 3, and it still doesn't click then 99.9% the ECU is the issue If the failure to click moves with the injector, then the injector is the problem. (It could still be the cable, but that has never been reported before)
 
So I swapped injectors #3 and #4 and cylinder #3 is still not "clicking" during the stationary test. Is there anything else in between the ECU and the injectors? I wouldn't think there would be any fuses on the outputs from the ECU. Sounds like the ECU needs replacement/repair.

Also, the ECU compartment was full of water though I have never opened them previously.
 
So I swapped injectors #3 and #4 and cylinder #3 is still not "clicking" during the stationary test. Is there anything else in between the ECU and the injectors? I wouldn't think there would be any fuses on the outputs from the ECU. Sounds like the ECU needs replacement/repair.

Also, the ECU compartment was full of water though I have never opened them previously.
I am currently driving so I am not going to look back but have you tried swapping computers
 
The box full of water and non clicking injector not moving, is proof enough. ECU is bad. check the other one too. Maybe it can be saved, but if it's also full of water it's potentially getting ready to fail.

Sorry for the bad news. there should be zero water inside the ECU box.

Either new ECU or send to repair.
 
The box full of water and non clicking injector not moving, is proof enough. ECU is bad. check the other one too. Maybe it can be saved, but if it's also full of water it's potentially getting ready to fail.

Sorry for the bad news. there should be zero water inside the ECU box.

Either new ECU or send to repair.
Thank you for all your help. Couldn't have done it without someone in the know.
 
Yeah water is not good. Seal mist have been bad and a flooding issue occured
 
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