My LS Swapped Yacht Is STUCK IN THE WATER BECAUSE OF ONE STUPID SENSOR!

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Engineer here. You’re causing an effect called entrainment when the caps open. The exhaust gas is causing a low pressure at the base of the pipe, ie differential pressure causes flow. You actually need a recirculation loop with a one way check valve. Leaving the cap on will create a no-flow region at the sensor tip and won’t read accurately. Edit: no-flow regions collect crud. That will definitely foul the sensor eventually. Edit2: you need the intake of the recirc line to be at a higher pressure than the exit for flow. You would need to intake further down the exhaust and the exit where your current sensor is located. Edit3: my degrees are in mechanical, manufacturing and nuclear engineering. Make fun all you want but at least I understand the science behind it. We use the same thing to pull vacuums on turbine condensers using air ejectors. Edit 4: after sleeping on it I think the sensor is too close to the exhaust outlet so you’re getting turbulent flow at the sensors tip. Moving the sensor further down the exhaust will probably fix the problem.

My dad's a man's owned many boats. He looked at me 1 day and said If you ever think about buying a boat, go to a dock and throw money in the water. If you like that, feeling, go buy a boat.

The new marine engines have O2 sensors so see what they use.

Ground ground ground!!! The exhaust manifold should be grounded straight to battery. Between rubber hose, gaskets and heavy powder coat to prevent salt corrosion, you may be grounding the sensor through the water and or bad connections through bolts.

I’ve been a consummate car guy for over 20 years, worked in the car business for 19 years and owned a shop for the last 6 years. If I’ve learned anything in that time it’s how much engineering goes into making engines work smoothly in all conditions, how many headaches you’ll encounter when modify or swap something, and how cool it is when it all works. That’s also what makes it satisfying, if it was always plug and play and not full of headaches and problem solving that first successful test drive of your project wouldn’t give you a high like no other. It’s the gearheads curse.

Engineer here. Some good comments on exhaust flow past the sensor. Have you tried checking the electrical connections and voltages to see if they are in spec? I highly suspect you have a grounding issue, and it’s burning out the sensors. Throwing parts at it is expensive, feel for you! Best of luck dude.

You identified the issue at 32:48, where you tried Oscar's add-on with the cap off. You said it was running lean because it was drawing air in from the capless end. So the actual exhaust system would be under vacuum at times, drawing water back towards the sensor.

I don't think I've ever been on a boat that didn't frustrate the crap out of it's owner on a regular basis, no reason for yours to be any different! 😂 Great job problem solving, can't wait for the next episode!

The problems are just beginning. That boat is going to behave very differently with those dramatically lighter motors. Also, I assume that all electrical components like starters and alternators are marinized units with certifications. Does not matter if you have fuel sniffers, if there is a fire your insurance will go right to the electrical components and claim you installed non marine parts into a boat. The first thing I would install is a fire suppression system in that bilge.

IDK if Holley does this, but with gm vehicles you have to relearn the O2 heater resistance when you replace them. My thought is 2 fold. First, Holley may have the same function for new o2 sensors to learn the O2 heater resistance in order not to over current it. Second, being that it is so close to the water in the exhaust, it may not be that water is killing the sensor. Instead the sensor may be too cold once it is in closed loop to functions properly. I've never messed with Holley ECU's (yet) but with GM ECU's I can see how that could potentially be an issue. Best of Luck. Love the Videos.

I'll never forget the episode where you said you were going full time on the YouTube game. Your perseverance in this episode and all the rest has been inspiring. I raise my glass to you! Videos like these are what keep me going on my own project. 🍻

For 2 guys who are not trained mechanics you work through things i think that your abilty to think outside the box pays off great job guys.

Reversion will get those O2s, I run a dry to the tip exhaust on mine which introduces water into the exhaust at the tip (manifolds / exhaust is still fully jacketed and cooled) . Perhaps you can move where water is introduced into the exhaust stream back a little.

Check if holley has a functionality to delay turning ON o2 sensors. Some o2 controllers offer an option to turn on the sensors a couple of minutes after the engine is turned ON so that any accumulated condensation is burned off

14:30-you need a siphon brake loop not uncommon to have in a boat where the engines sit low in the water. I would also recommend a water lift muffler or surge tube to prevent water intake when backing down.

Reposition or maybe shroud the O2 sensor somehow? Dang, just after I posted this, you came back from the parts store with the reposition shroud stuff.

I'm a major car buff, but the frustration level on the water is usually off the hook. Born and raised on the Jersey shore and when you decided to install hightech fuel injected gas V8's on a 30+ foot boat i go back in memory and the opposite is done installing Diesel engines. Good luck on you journey. The bilge is a tuff place to live safety is #1

In my experience, o2 sensors are mostly bad. They arent treated very well in the shipping process, so its hit or miss on getting a good one even if you go to the store to get it directly. They are tossed around and bumped against stuff so much before they ever meet the motor. You best bet is to buy a bunch of them and return them once you find a good one

Been loving this series, You can tell how excited Chris is to get this thing going!