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bad ECU due to too much oil???

Tom Kaptur

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I was having issues with port side engine - smoke and fuel coming out of exhaust and hard to start. Took it to the Yamaha dealer and the technician said the problem was due to way too much oil. He said the oil got into the air box and then into the wire harness ( through the connector) and traveled through the complete harness and into the ECU. The ECU is now damaged and in result the injector for the #1 cylinder is wide open - which is causing the poor running conditions. Is this possible? Has anyone else heard of or experienced this?
The marina where I keep my boat ( not yamaha dealer) performed my oil change last May and I am questioning them for the too much oil... and asking them to pay for the $3,400 repair - two new harnesses and ECU. They do not believe the analysis of the yamaha technician and say they never heard of such a thing. Also asked why did it take so long to happen. The Y tech. said it can take that long for the oil to travel through.... and said it happens all the time.

Thank you for the help.
 

TheGriz

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I'll be following this closely. I had oil purge up through the breather in my airbox this week and shortly after my engine quit running. I did some diligence, but gave up and am awaiting feedback from my dealer.
 

Bruce

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This is the first time I have heard of oil in the ECU. Water happens but never heard of oil.

You should be able to see the oil if this is the issue. Your air filter should be soaked with oil as well.

You need to create the best documentation that you can. Get photographs, preserve damaged parts, get a signed, written statement from the dealer.

The repair also seems way too expensive.
 

Murf'n'surf

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From what I have read here for many years is that a bad injector causes too much resistance in the ecu and burns something up in the ecu and rendering it bad. Oil traveling down the wire harness to the ecu and causing damage is not possible in my opinion.

As for the over filled oil level.... its a common problem that people who are not familiar with the dry sump system make. Vacuum out some oil and get those injectors tested for proper resistance. Maybe look for a local Yamaha shop?
 

Jgorm

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I'd ask to see a picture if the ecu opened up and have oil everywhere. Sounds like bs. Oil would be everywhere for months for that to be feasible.
 

scokill

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I think it's plausible to need your ECU replaced but they could chain of events backwards. Bad ECU causing injector to dump gas into engine raising gas/oil level and that mixture getting in to air box.
 

itsdgm

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@Tom Kaptur welcome and sorry to hear about your issue.

The bad ECU causing a stuck injector (almost always cylinder 1) has happened to several guys. As others have stated, open up the ECU, usually there's water inside that apparently gets in there. Some guys have said that it's possible that the water gets in there simply by the location it's placed in and that Yamaha has moved it over the years to better protect it.

Imho, your oil seeming to be overfilled is more that likely a sign of the stuck fuel injector. You stated that you could see unburned fuel coming out the exhaust. But unburned fuel also will pass the piston rings and find its way into the crankcase. This increases the level of the oil. If run too long (I don't know how long this would take) the increased oil level will that blow back into the air intake through the breather tube and ruin your air filter.

Other things to check. How does the viscosity of the oil feel compared to the oil in the other engine. Also, How's the oil level on the other engine? More than likely whoever changed the oil would've done the same on both engines. So that would be a good base line indicator.

Anyway, good luck with the repair. Keep us posted.
 

Scottintexas

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glad to have you on board, sorry we had to meet like this,

I agree with the others, a bad injector certainly could dump fuel increasing the oil level but this would be the first time in 8 years I've ever heard of sore much oil that it overflows the breather, travels through a connector harness and back up to the ecu and causes it to fail (and we've seen some people with oil coming out their breathers before),

My opinion, find another mechanic, just because he's a Yamaha tech doesn't mean he's honest or knowledgeable.

I'd rather have someone I trust work on it (it doesn't have to be a boat dealer, a PWC shop can do it also)
 

Murf'n'surf

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I think it's important to review the condition of the injectors. Subject them to a resistance test to see if they are within specs.

It's my understanding that the bad injector causes high resistance within the ecu thus causing the ecu to fail.
 

YamahaForMe

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if there is a significant amount of fuel in the oil, you will definitely smell it on the dipstick.

Steve
 

Jgorm

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Based on the picture, getting oil in the ecu from oil leaking down the cable is 100%bs.
 

Darrell40

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Hey all! I’m new here and am in the same boat. Lol. # 1 injector dumping gas. I do know my brother in law did over fill oil 100%. Not sure if oil got into the ecu but it is possible. (explanation)
Dodge Durango, power steering switch goes bad and fluid ends up in computer, not by spraying on it but electrical current carries it to the computer I know this because it also comes out of the radio controls and the overhead controls.
Not saying that’s what happened but still possible. That being said does anyone know where I can get a reasonably priced ecu and wiring harness??
 
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njmr2fan

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Am I understanding that they feel the oil physically moved to the ECU to fry it, or that oil contacted the pins in the plug and short circuited the ECU?
 

Darrell40

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That’s what I understood from the original post
 

Tom Kaptur

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Thanks for all the input, sorry I did not come back earlier but I must have missed the notifications and truthfully I forgot about this.

I ended up taking my boat to a second dealer and spoke with there Jet boat expert. He basically looked at me line the first story was complete BS. And it was- basically it was just the ECU went bad (which I guess happens often). Anyway, it was causing cylinder 1 to stay wide open which in turn was dumping extra fuel which was eventually mixing with the oil ( what is referred to making oil) and then working it’s way into the air box. It had nothing to do with too much oil and my wire harnesses were fine. The first dealer was trying to screw me and charge over 3k vs paying like $1800....
 

Murf'n'surf

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Thanks for all the input, sorry I did not come back earlier but I must have missed the notifications and truthfully I forgot about this.

I ended up taking my boat to a second dealer and spoke with there Jet boat expert. He basically looked at me line the first story was complete BS. And it was- basically it was just the ECU went bad (which I guess happens often). Anyway, it was causing cylinder 1 to stay wide open which in turn was dumping extra fuel which was eventually mixing with the oil ( what is referred to making oil) and then working it’s way into the air box. It had nothing to do with too much oil and my wire harnesses were fine. The first dealer was trying to screw me and charge over 3k vs paying like $1800....
Make sure they ohm test all of your injectors as a bad injector can damage your ECU by overamping.
 

itsdgm

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Thanks for all the input, sorry I did not come back earlier but I must have missed the notifications and truthfully I forgot about this.

I ended up taking my boat to a second dealer and spoke with there Jet boat expert. He basically looked at me line the first story was complete BS. And it was- basically it was just the ECU went bad (which I guess happens often). Anyway, it was causing cylinder 1 to stay wide open which in turn was dumping extra fuel which was eventually mixing with the oil ( what is referred to making oil) and then working it’s way into the air box. It had nothing to do with too much oil and my wire harnesses were fine. The first dealer was trying to screw me and charge over 3k vs paying like $1800....
That sounds more like it. I’m pretty sure that’s the same signs and symptoms that would indicate an ECU issue. One thing to note. There is a possibility that a sticky injector could cause the ECU to go bad. More than likely though if it’s the #1 cylinder, it’s just the ECU. But it might be worth asking the mechanic if it would be a good idea to clean the injectors also.
 

itsdgm

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Darrell40

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Has anyone ever had any dealings with regulator rectifier? Just wondering if it’s worth it to go that route and have the ecm rebuilt?
 
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