Yamaha 1.8L HO Fuel Injector Connector

[jtwrace]

I'm posting this here rather then the dedicated PWC section so all with this motor have a chance to see it.

While this is a boating forum, thought I'd share as there is a large Yamaha presence on here and this could hopefully save someones nightmare should they have the same issue. This is on my 10 month old 2019 Yamaha WaveRunner with 135 hrs. I was out deep in a ride at WOT when suddenly it dropped a cylinder (no codes or alarms). At first I really thought the engine dropped a valve but my only concern was try to make it as far as I could to safety rather then being out in the middle of the large lake I was in. Thank goodness I didn't go ocean as we planned initially and I was in the previous week. Anyway, after much throttle work to keep it going I was able to get back to the ramp.

I looked at all the usual suspects and all seemed normal. When I returned home I plugged the CanDOO system into the unit and there were no codes or alarms either. First I checked spark on each cylinder - yep, all good. Checked each coils resistance - all good. Plugs all looked "normal" too, compression solid on all cylinders as well. Fuel pressure? Yep - checked good. I then fired each fuel injector and heard each one fire. I was really stumped at this point as we know it takes air and fuel ICE to work and according to my basic tests, I had it. I then started the engine and while looking at the computer all seemed fine again but it really had a misfire at certain RPMs. I used a screwdriver like the old days (I'm 45) as stethoscope and could hear each injector pulse but when I got to the misfire it was really hard to tell. Being that I had spark which I could physically see with each plug into a coil out of the engine and fire each coil it narrowed it down specifically to an injector. Well, I checked each injector wire going into the connector and found the issue.

The pin in the connector had broken thus causing the misfire. I wanted to absolutely make certain that this is indeed the root cause not a valve spring or other that broke and created a harmonic that broke the pin which really seems like an odd failure to me. So I was able to source a pigtail from O'Reilly's for $4 and give it a shot. I removed the other pin from the connector and just used some alligator clips to the pigtail and suddenly it was firing on all four cylinders. As you can see, I didn't want to modify the harness as this is a warranty issue but wanted to water test which I did and it was fine.

Again, I share this story to offer help should any of your Yamaha engines use the same harness/connector.

 

[buckbuck]

Nice trouble shooting. What engine is that?

 

[Weeb]

Thanks for the info. I would have taken it back to the dealer because i would never have found that lol

 

[jtwrace]

What engine is that?

It's in the tittle that you clicked on.

 

[buckbuck]

Ha

 

[aaron jansen]

I'm having the same issue, I first tried a nissan 350z plug, it fit, but did not solve my issue.

I am going to try the one you showed tomorrow and see if that works.

Based on the bastardized tests I ran, it looks like it won't spark with a broken fuel injector? I could be wrong, but when I pulled the plug and coil to test the compression, I didn't see a spark that I could tell. I tried that coil and plug in a different cylinder and it worked fine. The trouble cylinder wire harness for the coil is fine, no broken pins. All the other wires are wrapped up so tight and tucked away, its going to be a mess taking it apart if this connector doesn't work.

My boat is a 2015 1.8HO with 250 hours approx.

 

[jtwrace]

I'm having the same issue, I first tried a nissan 350z plug, it fit, but did not solve my issue.

I am going to try the one you showed tomorrow and see if that works.

Based on the bastardized tests I ran, it looks like it won't spark with a broken fuel injector? I could be wrong, but when I pulled the plug and coil to test the compression, I didn't see a spark that I could tell. I tried that coil and plug in a different cylinder and it worked fine. The trouble cylinder wire harness for the coil is fine, no broken pins. All the other wires are wrapped up so tight and tucked away, its going to be a mess taking it apart if this connector doesn't work.

My boat is a 2015 1.8HO with 250 hours approx.

The coil will fire separate of the injector pulsing - they are totally separate. You can pull all the spark plugs and leave the 3 cylinders coils disconnected then place one spark plug into one coil and crank the engine to see if you have spark on that cylinder. You MUST disconnect each fuel injector on each cylinder before you do this. Not only do you not want to dump raw fuel into a cylinder...you now have spark! If that checks out OK, then you can check the voltage at each fuel injector with the key "on" like you will get ready to start it. Also, you can, while the engine is running; just disconnect each coil plug and see if the RPM's drop to see if there is a "dead" cylinder. Does this make any sense?

 

[aaron jansen]

The coil will fire separate of the injector pulsing - they are totally separate. You can pull all the spark plugs and leave the 3 cylinders coils disconnected then place one spark plug into one coil and crank the engine to see if you have spark on that cylinder. You MUST disconnect each fuel injector on each cylinder before you do this. Not only do you not want to dump raw fuel into a cylinder...you now have spark! If that checks out OK, then you can check the voltage at each fuel injector with the key "on" like you will get ready to start it. Also, you can, while the engine is running; just disconnect each coil plug and see if the RPM's drop to see if there is a "dead" cylinder. Does this make any sense?

Yeah, makes sense, pulling the coil plugs was what I was testing to confirm cylinder 1 was the problem.

Is the spark really easy to see? I pulled them during the middle of the day and maybe I wasn't as focused with the open cylinder blasting.

 

[aaron jansen]

The coil will fire separate of the injector pulsing - they are totally separate. You can pull all the spark plugs and leave the 3 cylinders coils disconnected then place one spark plug into one coil and crank the engine to see if you have spark on that cylinder. You MUST disconnect each fuel injector on each cylinder before you do this. Not only do you not want to dump raw fuel into a cylinder...you now have spark! If that checks out OK, then you can check the voltage at each fuel injector with the key "on" like you will get ready to start it. Also, you can, while the engine is running; just disconnect each coil plug and see if the RPM's drop to see if there is a "dead" cylinder. Does this make any sense?

I tried the connector you used. Seemed to work. I pulled the cylinder 2 coil and it didn't stall. It went rough but stayed running when before it would immediately cut out. This time it was able to adjust and stay running.

Taking it out for a water test tonight to see how it goes.

 

[aaron jansen]

Still one cylinder down. Not sure if injector needs replacing. Going to pull them tomorrow and do a test.

 

[aaron jansen]

I did a test tonight, spark in cylinder 1. That injector has to be bad. They are new plugs and no sign of wear. I tested with a multi meter the wires from the new connector and power was flowing.
I did a bastardized compression test and it sounded good.

 

[Ottawa]

I'm posting this here rather then the dedicated PWC section so all with this motor have a chance to see it.

While this is a boating forum, thought I'd share as there is a large Yamaha presence on here and this could hopefully save someones nightmare should they have the same issue. This is on my 10 month old 2019 Yamaha WaveRunner with 135 hrs. I was out deep in a ride at WOT when suddenly it dropped a cylinder (no codes or alarms). At first I really thought the engine dropped a valve but my only concern was try to make it as far as I could to safety rather then being out in the middle of the large lake I was in. Thank goodness I didn't go ocean as we planned initially and I was in the previous week. Anyway, after much throttle work to keep it going I was able to get back to the ramp.

I looked at all the usual suspects and all seemed normal. When I returned home I plugged the CanDOO system into the unit and there were no codes or alarms either. First I checked spark on each cylinder - yep, all good. Checked each coils resistance - all good. Plugs all looked "normal" too, compression solid on all cylinders as well. Fuel pressure? Yep - checked good. I then fired each fuel injector and heard each one fire. I was really stumped at this point as we know it takes air and fuel ICE to work and according to my basic tests, I had it. I then started the engine and while looking at the computer all seemed fine again but it really had a misfire at certain RPMs. I used a screwdriver like the old days (I'm 45) as stethoscope and could hear each injector pulse but when I got to the misfire it was really hard to tell. Being that I had spark which I could physically see with each plug into a coil out of the engine and fire each coil it narrowed it down specifically to an injector. Well, I checked each injector wire going into the connector and found the issue.

The pin in the connector had broken thus causing the misfire. I wanted to absolutely make certain that this is indeed the root cause not a valve spring or other that broke and created a harmonic that broke the pin which really seems like an odd failure to me. So I was able to source a pigtail from O'Reilly's for $4 and give it a shot. I removed the other pin from the connector and just used some alligator clips to the pigtail and suddenly it was firing on all four cylinders. As you can see, I didn't want to modify the harness as this is a warranty issue but wanted to water test which I did and it was fine.

Again, I share this story to offer help should any of your Yamaha engines use the same harness/connector.

View attachment 117806View attachment 117807View attachment 117809View attachment 117808

I seem to be having same problem with misfire at my number one cylinder , went through all the same check and even removed all my injectors has them tested and cleaned. They are telling me it’s a poor electrical connection but I’ve done a resistance check across all injector connectors and they have same reading. Was this the case for you? it is intermittent problem for me so hard to trouble shoot.

 

[jtwrace]

I seem to be having same problem with misfire at my number one cylinder , went through all the same check and even removed all my injectors has them tested and cleaned. They are telling me it’s a poor electrical connection but I’ve done a resistance check across all injector connectors and they have same reading. Was this the case for you? it is intermittent problem for me so hard to trouble shoot.

Did you pull on each wire going into the connector? My voltage was fine at the connector and I could even get each injector to pulse using my CanDoo system. It wasn't until scratching my head enough that I decided to really pull on the wire that it came right out of the connector. The thin contact was just arcing while in the garage whereas under load it was a real misfire.

 

[Tobes]

I'm having the same issue, I first tried a nissan 350z plug, it fit, but did not solve my issue.

I am going to try the one you showed tomorrow and see if that works.

Based on the bastardized tests I ran, it looks like it won't spark with a broken fuel injector? I could be wrong, but when I pulled the plug and coil to test the compression, I didn't see a spark that I could tell. I tried that coil and plug in a different cylinder and it worked fine. The trouble cylinder wire harness for the coil is fine, no broken pins. All the other wires are wrapped up so tight and tucked away, its going to be a mess taking it apart if this connector doesn't work.

My boat is a 2015 1.8HO with 250 hours approx.

Did you ever get this figured out?

So apparently, I am not getting spark to #1 cylinder. Tested the coil and it is fine. So there is no command for a spark. I may be ripping apart my wiring harness...........

 

[David Martin]

Have you check the voltage at the injector(wire harness side) you should get around 12.22 to 12.38 volts.......this is what they call the battery voltage side. This reading along with coil voltage SHOULD BE DONE ON A FULL CHARGED BATTERY if you want accrete numbers. Then run a ohm check on the injector. The ohm range is 11.5 to 12.5 if your impendence/ohm go up past this it will take a lot more voltage to move the injector. This ohm reading is testing the wiring inside the injector looking for a soft/short driving the impedance/ohm up. Also the injectors ohm can be done without removal.

The volt test on the wire harness side of the injector is reading the battery voltage you need the voltage just after the starter bump...bump it don't crank it.........the first stable voltage is the actual injector voltage mine was 12.22 to 12.38 after that the voltage will steadily increase to around 12.60 and that is the CDI capacitor bleeding off going above your normal battery voltage.

Most times the wire is broken at the connector in the wire connector where it is crimped not something you can see most times without removing the pins inside the connector............you could back probe the wire connector to read voltage if you are not getting voltage using method in service manual.

The coil test is straight forward as you read it on the diagram except you can ohm the coils with the meter and the 2 left pins in the coil my meter was set to 2000ohm and I got 960 to 976 ohms on the coils it just testing the coil wires inside on how much energy the battery will take to fire the coil.

Hope this helps