2015 Moomba mondo surf edition \4238 engine fault code question

[Wdavid]

Each time we go out and fill the ballast up and begin to surf the check engine light goes on. Per a thread I read on here I replaced both O2 sensors. I am now trying to burn through the remaining gas in the tank running laps around our lake, just in case it is a gas issue. No check engine light when I am running 30 mph to burn gas. I am now going to fill the tank with 91 non-ethanol gas. Again, the orange check engine only comes on when the motor is under high stress, surfing for example. Any other thoughts on what it could be? I do not have the correct tools or knowledge to check the fuel line pressure.

[Holdmybeer]

Each time we go out and fill the ballast up and begin to surf the check engine light goes on. Per a thread I read on here I replaced both O2 sensors. I am now trying to burn through the remaining gas in the tank running laps around our lake, just in case it is a gas issue. No check engine light when I am running 30 mph to burn gas. I am now going to fill the tank with 91 non-ethanol gas. Again, the orange check engine only comes on when the motor is under high stress, surfing for example. Any other thoughts on what it could be? I do not have the correct tools or knowledge to check the fuel line pressure.

Go around and check all exhaust connections. If you changed the O2 sensor and still getting the code, you have a leak allowing fresh air in. Tighten all the V-band clamps.

[Wdavid]

[QUOTE=Holdmybeer;371452]Go around and check all exhaust connections. If you changed the O2 sensor and still getting the code, you have a leak allowing fresh air in. Tighten all the V-band clamps.[/QUOTE

I hate to ask the obvious, but can you specifically point out to me what clamps...as I look at the engine there seem to be a lot! Sorry. My engine experience is limited!

[2in2out]

Is it possible it’s a collapsed CAT matrix? If I remember there were issues with Indmar CATs during those years in which the matrix would collapse giving O2 sensor faults and a number of other misc codes.

If you can visualize the honeycomb, see if it’s intact.


Currently boatless

[Wdavid]

Go around and check all exhaust connections. If you changed the O2 sensor and still getting the code, you have a leak allowing fresh air in. Tighten all the V-band clamps.


I hate to ask the obvious, but can you specifically point out to me what clamps...as I look at the engine there seem to be a lot! Sorry. My engine experience is limited!

[Wdavid]

I hate to ask the obvious, but can you specifically point out to me what clamps...as I look at the engine there seem to be a lot! Sorry. My engine experience is limited!

[Holdmybeer]

I hate to ask the obvious, but can you specifically point out to me what clamps...as I look at the engine there seem to be a lot! Sorry. My engine experience is limited!

Check these connections.
Back of the engine can access through rear lockers/v-drive doghouse. CATS are the canisters on the exhaust.

29940

[Wdavid]

Awesome! Thank you.

[parrothd]

Awesome! Thank you.


Just making sure you checked ALL the o2 sensors, there's 4, 2 before and 2 after.

Usually it's the after 02s that go bad and I got easily got confused and change the wrong one. :)

Sorry the ones on the exhaust manifold.

[parrothd]

Just making sure you check ALL the o2 sensors, there's 4, 2 before and 2 after.

Usually it's the after 02s that go bad and I got easily got confused and change the wrong one. :)

Also if the light comes on when you fill the ballast it means the wall is collapsing into the engine and pressing on the O2 sensor wire.

[Wdavid]

Thank you.

[Wdavid]

Also if the light comes on when you fill the ballast it means the wall is collapsing into the engine and pressing on the O2 sensor wire.

Ok. So I changed the two closest to the front, I think the post cat o2 sensors. I now need to change the other two on the actual exhaust manifold? Any chance you could circle where they should be located on a picture? I am out of state for a bit away from the boat but when I get back I would like to fix it quick as my kids will want to surf I am sure.


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[Wdavid]

Also if the light comes on when you fill the ballast it means the wall is collapsing into the engine and pressing on the O2 sensor wire.

Will check that out too. Thank you.


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[Holdmybeer]

Wanted to help you out with O2 issues.

First off, are you still getting this fault? If so, please post the whole fault code.

O2 sensors are labeled/programmed a certain way in the ECU. Since you drive a boat on the opposite side of a car and the motor is flipped the labeling and locations are the same.

Bank 1 = Starboard side (Driver's side)
Bank 2 = Port side (Passenger's side)

Sensor 1 is before the CAT
Sensor 2 is after the CAT

Looking at the picture I posted earlier, there are 2 sensors, 1 with a blue wire at the manifold, and 1 in the upper CAT chamber. Manifold is Sensor 1, upper CAT is Sensor 2. Sensor 1 controls fuel/air ratio and if either Bank 1 or Bank 2 sensor 1 is bad, the motor will run rough once up to temperature. If sensor 2 is bad, it will run fine but throw a code and drive you crazy.

You say you changed the 2 closet to the front, I assume the manifold units with the blue wire. Instead of changing the other 2, focus on the code and determine which side needs changed. You should have only needed 1 sensor.

29949

[Wdavid]

Wanted to help you out with O2 issues.

First off, are you still getting this fault? If so, please post the whole fault code.

O2 sensors are labeled/programmed a certain way in the ECU. Since you drive a boat on the opposite side of a car and the motor is flipped the labeling and locations are the same.

Bank 1 = Starboard side (Driver's side)
Bank 2 = Port side (Passenger's side)

Sensor 1 is before the CAT
Sensor 2 is after the CAT

Looking at the picture I posted earlier, there are 2 sensors, 1 with a blue wire at the manifold, and 1 in the upper CAT chamber. Manifold is Sensor 1, upper CAT is Sensor 2. Sensor 1 controls fuel/air ratio and if either Bank 1 or Bank 2 sensor 1 is bad, the motor will run rough once up to temperature. If sensor 2 is bad, it will run fine but throw a code and drive you crazy.

You say you changed the 2 closet to the front, I assume the manifold units with the blue wire. Instead of changing the other 2, focus on the code and determine which side needs changed. You should have only needed 1 sensor.

29949

Ok. First, Thank you for following up. I am currently out of state but before I left I ran the boat hard at 30 mph for 45 minutes. No light. With that said, earlier in the day I got a light after I filled the ballasts snd started surfing. Basically under extreme load it throws the code. Someone said I need to check to make sure the wall is not bending from the ballast and bumping a sensor. I will do that upon my return. The exact code is 4238 FMI 0. See attached. I did change the bank 1 sensor 2 and bank 2 sensor 2. In addition to making sure all the connections are tight. Should I next change the other two O2 sensors bank 2 sensor 1 and bank 2 sensor 2? 29951


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[Wdavid]

Ok. First, Thank you for following up. I am currently out of state but before I left I ran the boat hard at 30 mph for 45 minutes. No light. With that said, earlier in the day I got a light after I filled the ballasts snd started surfing. Basically under extreme load it throws the code. Someone said I need to check to make sure the wall is not bending from the ballast and bumping a sensor. I will do that upon my return. The exact code is 4238 FMI 0. See attached. I did change the bank 1 sensor 2 and bank 2 sensor 2. In addition to making sure all the connections are tight. Should I next change the other two O2 sensors bank 2 sensor 1 and bank 2 sensor 2? 29951


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Use these I believe? 29952
29953


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[Wdavid]

Should have said should I now change out bank 2 sensor 1 and bank 1 sense or 1 above. Also, not sure if this might have caused some type of underlying issue that has resulted in the code but at one point one of my rear 910 lb ballast bag connections came undone and dumped all the water into the hood. The sump did its job but there was a lot of water around the engine. Could that have caused a crack in the manifold or something else if the water hit it when it was hot?


Ok. First, Thank you for following up. I am currently out of state but before I left I ran the boat hard at 30 mph for 45 minutes. No light. With that said, earlier in the day I got a light after I filled the ballasts snd started surfing. Basically under extreme load it throws the code. Someone said I need to check to make sure the wall is not bending from the ballast and bumping a sensor. I will do that upon my return. The exact code is 4238 FMI 0. See attached. I did change the bank 1 sensor 2 and bank 2 sensor 2. In addition to making sure all the connections are tight. Should I next change the other two O2 sensors bank 2 sensor 1 and bank 2 sensor 2? 29951


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[Holdmybeer]

Don't think the water hurt you at all. It certainly came out fast but only through a 1" hole so the bilge doing its job would be fine. Also the manifolds are cooled from the raw water impeller and can be touched while running.

As others suggested, the walls could easily be smashing that wire. The port side is in a horrible place from the factory and my blue wire covering is messed up but doing is damaged throwing codes. See if you can re-route the wire and plug it back in and fill the ballast. It could be that easy. If the blue shielding is damaged on either or both start the boat and wiggle the wires and see if you can get the code to pop up.

Good luck and keep us posted

[Wdavid]

Don't think the water hurt you at all. It certainly came out fast but only through a 1" hole so the bilge doing its job would be fine. Also the manifolds are cooled from the raw water impeller and can be touched while running.

As others suggested, the walls could easily be smashing that wire. The port side is in a horrible place from the factory and my blue wire covering is messed up but doing is damaged throwing codes. See if you can re-route the wire and plug it back in and fill the ballast. It could be that easy. If the blue shielding is damaged on either or both start the boat and wiggle the wires and see if you can get the code to pop up.

Good luck and keep us posted


Don't think the water hurt you at all. It certainly came out fast but only through a 1" hole so the bilge doing its job would be fine. Also the manifolds are cooled from the raw water impeller and can be touched while running.

As others suggested, the walls could easily be smashing that wire. The port side is in a horrible place from the factory and my blue wire covering is messed up but doing is damaged throwing codes. See if you can re-route the wire and plug it back in and fill the ballast. It could be that easy. If the blue shielding is damaged on either or both start the boat and wiggle the wires and see if you can get the code to pop up.

Good luck and keep us posted

I changed out the pre O2 sensor after starting the engine and jiggling it. It produced the engine code when jiggled. Additionally, it was noticeably bent from the wall coming in when the ballast bags were full. To that point, some of the plastic from the sensor was on the wall. Once changed, the code went away.

I need to reinforce the engine wall.
Looked at the wakemakers solution. Any other DIY solutions you aware of?


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[Holdmybeer]

You can buy the same aluminum at a local hardware store. Drill the holes and bolt them in.

Use nylon lock nuts, and washers on the plastic side. Run them vertical.
While at it add some sound deadener material to the engine facing side. It will help with noise. Then cover the inside of the v-drice3 cover (aka doghouse).

Good luck and good to hear you found the sensor.

[Wdavid]

You can buy the same aluminum at a local hardware store. Drill the holes and bolt them in.

Use nylon lock nuts, and washers on the plastic side. Run them vertical.
While at it add some sound deadener material to the engine facing side. It will help with noise. Then cover the inside of the v-drice3 cover (aka doghouse).

Good luck and good to hear you found the sensor.

Thank you. When you say plastic side, is that the ballast side where the metal is mounted and the nuts go through to the engine side?


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[Holdmybeer]

The metal goes engine side. Nuts go engine side.
Flat washers and round head or button head bolts go ballast side.
Nothing sharp against the bags....:cool:

Bolt example.
29968

[Wdavid]

I replaced the pre o2 sensor on the starboard side and it solved the problem. The bag was indeed encroaching in the engine area and the O2 sensor was being impacted.

[sandm]

I replaced the pre o2 sensor on the starboard side and it solved the problem. The bag was indeed encroaching in the engine area and the O2 sensor was being impacted.

congrats.
did you fix the divider wall issue? was that the root cause of the failure?

[Wdavid]

congrats.
did you fix the divider wall issue? was that the root cause of the failure?

Yep, the divider was pushing so much into the sensor that part of the plastic on the sensor had worn off on the wall... Yes, I am heading to the lake tonight to install a fix.

[Wdavid]

Also if the light comes on when you fill the ballast it means the wall is collapsing into the engine and pressing on the O2 sensor wire.

I should give you credit parrothd...that is exactly what was causing the issue....thank you.