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She let me down! Need her for next weekend!


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2012 VLX with 350 Monsoon. 330 hrs, had a good day and sat for about an hour. Fired her up to go back out, felt a bit lumpy like missing on a cylinder. Idle out and service engine soon lights up. Idle out for about 4 minutes to clear no wake zone, hit throttle and rough as could be then dies completely. Smelled like something burning, first thought rubber exhaust connections. they checked out ok not that hot, maybe fuel mix way off and that was it, don't know. Fired back up and idled back to trailer. After getting back home and looking around, noticed the O2 sensors on top of exhaust were both showing crushed and some bare wires. Look under tray that sets above it and notice that the two molded clearance areas in the tray are not above (about 1" inside the bump outs) the O2 sensors and the tray has always been smashing these wires. Nice job Malibu. Any way, anyone think this may be my problem? Also, anyone know if I can get these Sensors at an auto parts store? Part # please?

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The O2 sensors provide feedback for the ECM to run the engine correctly, so it should run worse without them, but I would think that the open loop mode would run better than that.

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I had basically the same sagging issues until I made an angle brace for the tray and riveted it to the inside of the back of the tray. When Malibu cut the "U" shaped clearance for the walk over shock it looked liked they used a quickie saw in the dark. I also ended up making some rear transom support "L" brackets to support underneath the tray lip for the back of the tray where it was cracking. They sit on the transom opposite the tray brace so there is a lot of support provided now and no more cracks in the tray.

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I had basically the same sagging issues until I made an angle brace for the tray and riveted it to the inside of the back of the tray. When Malibu cut the "U" shaped clearance for the walk over shock it looked liked they used a quickie saw in the dark. I also ended up making some rear transom support "L" brackets to support underneath the tray lip for the back of the tray where it was cracking. They sit on the transom opposite the tray brace so there is a lot of support provided now and no more cracks in the tray.

wdr

You responded to one of my other threads here. That problem was an easy fix, this one maybe a bit more spendy! Two O2 $75 each and may not be the problem.

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If I were you, I would try cleaning everything with a blast of air, then strip the wire back. Then using flux and a hobby solder gun that does not get too hot and put some solder on the frayed wire and then black tape it and in finality use liquid tape to seal. Probably about $15 fix. Use a very thin layer of solder so you don't change the resistance too much. Worse case is you still have to change out the sensors. Good luck, and safe and happy boating!

Edited by BlackBluMalibu
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You might get away with soldering them for a little while, but unless you raise or otherwise keep the tray from sagging it is going to do them in again. I know we all want to save money, but because the O2 sensors complete the closed loop system you really need a reliable sensor in place. IIWM, I would spring for the new sensors and remove the tray until I could; raise he tray up if possible or cut out the rub areas where the O2 sensors wore the tray down with a hole saw so the sensors don't contact it any more. You can probably find some domed cup inserts to fit into the cut holes to cover the sensors to keep them from making contact with items in the tray and have an OEM finished look without resorting to buying a new tray which is going to sag again anyway. JM2C

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martinarcher

It doesn't look like the wire to the O2 sensor is cut but the insulation is sure cut pretty good. If the wires to the sensors shorted I could see it causing some really bad performance. The O2 sensor voltage that is fed back into the ECU tells the ECU how rich or lean the mixture is currently running. It can then add/remove fuel by changing the injector pulse width to tune the mixture until it's right on the money. The ECU reads the O2 sensor voltages 100's of times per second and tunes the mixture while we happily ride behind the boat.

This is called 'closed loop' meaning the ECU is reading the sensors and using the feedback from the sensors and tuning the engine with that feedback. If the sensors are unavailable or not working (out of range etc) the ECU will revert to 'open loop' meaning the ECU will run the engine without the O2 sensor feedback using a pre programmed fuel map. This map is plenty good enough to run the engine smoothly and is actually used on every outing until the engine reaches operating temperature.

I guess to answer the question, I would say if the ECU was still running in closed loop and getting intermittent or bad data from the O2 sensors it could cause the symptoms you describe but it sure sounds unlikely to me and I would expect the ECU to fall back to open loop. I would patch up the O2 sensor wiring or change them and give it another try first but I'm not sure it will be the cure. I hope it is though!

One question, can you read an OBD codes off the ECU? If so it would sure be worth reading the codes before throwing parts at it. I bought a cheap $15 bluetooth dongle online and can read codes and watch all my cars sensors in realtime with my phone (Android app called Torque). It incredible and the best $15 I've ever spent to help troubleshoot issues with ECU's and engine sensors.

Good luck man!!

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It doesn't look like the wire to the O2 sensor is cut but the insulation is sure cut pretty good. If the wires to the sensors shorted I could see it causing some really bad performance. The O2 sensor voltage that is fed back into the ECU tells the ECU how rich or lean the mixture is currently running. It can then add/remove fuel by changing the injector pulse width to tune the mixture until it's right on the money. The ECU reads the O2 sensor voltages 100's of times per second and tunes the mixture while we happily ride behind the boat.

This is called 'closed loop' meaning the ECU is reading the sensors and using the feedback from the sensors and tuning the engine with that feedback. If the sensors are unavailable or not working (out of range etc) the ECU will revert to 'open loop' meaning the ECU will run the engine without the O2 sensor feedback using a pre programmed fuel map. This map is plenty good enough to run the engine smoothly and is actually used on every outing until the engine reaches operating temperature.

I guess to answer the question, I would say if the ECU was still running in closed loop and getting intermittent or bad data from the O2 sensors it could cause the symptoms you describe but it sure sounds unlikely to me and I would expect the ECU to fall back to open loop. I would patch up the O2 sensor wiring or change them and give it another try first but I'm not sure it will be the cure. I hope it is though!

One question, can you read an OBD codes off the ECU? If so it would sure be worth reading the codes before throwing parts at it. I bought a cheap $15 bluetooth dongle online and can read codes and watch all my cars sensors in realtime with my phone (Android app called Torque). It incredible and the best $15 I've ever spent to help troubleshoot issues with ECU's and engine sensors.

Good luck man!!

Does the dongle just plug in to the ECU reader port?

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You might get away with soldering them for a little while, but unless you raise or otherwise keep the tray from sagging it is going to do them in again. I know we all want to save money, but because the O2 sensors complete the closed loop system you really need a reliable sensor in place. IIWM, I would spring for the new sensors and remove the tray until I could; raise he tray up if possible or cut out the rub areas where the O2 sensors wore the tray down with a hole saw so the sensors don't contact it any more. You can probably find some domed cup inserts to fit into the cut holes to cover the sensors to keep them from making contact with items in the tray and have an OEM finished look without resorting to buying a new tray which is going to sag again anyway. JM2C

8B0D9A34-1335-464E-9FBB-53300ABE769F_zpsThis should take care of the clearance problem. Will definitely keep an Eye on them when I put it back together. As far as a cup holder, that would never work as it was upside down for that, this is the underside of the tray.. Would also warm your beverage rather quickly.

  • Like 1
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Update:

Distributor cap corroded. All makes sense now. Original owner stored on lift for first 2 seasons. Moist environment constant for probably 3 or 4 months out of the year. I used it last year and till this point this year no problems. Spend a couple hours hydrofoiling then make a run for marina slip to ride out a storm. Almost made it under cover except the rain blew into boat even under cover. Lots of it. Now very hot engine compartment plus steamy water probably got moist in cap after setting and soaking for an hour or two. Restart and probably acting up from wet and corroded contacts. At any rate, I usually change wires, plugs and rotor/ cap at 400 hours. Didn't quite make that cause now I'm at 330 hrs. Live and learn.

  • Like 3
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