Anyone have an issue if I ask for help here troubleshooting a fuel injection or ignition issue with a 2014 LY6 Gen 4 LS engine in a boat? All the typical boating forums don’t have any real experience with these “later model” engines.

Thanks in advance,

TD

 

Ask away! You're in the right spot. Lots of talented individuals here to help you out.

 

Cool, appreciate it.

ok, here goes:

Boat is a 2014 with original engine, 400 hours on it. It’s advertised as a Volvo Penta V8-380-C-D. 380 is the crank hp, C stands for catalyst equipped, and D is the engine revision. From what I can deduce, it’s a Gen 4 LS because it is 6.0l displacement and port injected. I think it’s based on the vortec truck engine.

A couple seasons ago, I started getting an intermittent check engine light and limp mode, typically would happen after powering away after sitting at anchor for 5-6 hours, so I thought there was a heat soak correlation (5-6 hours after hard running and things are still pretty hot in a boat’s engine bay). I then bought a Volvo Penta Digital Gauge Bluetooth app that allowed me to also read fault codes. The SPN 4236 FMI 1 code that would get logged is described as “Closed Loop Bank 1 Low” from what I’ve been able to find online. Possible causes are listed as primary O2 sensor or plugs.

The code was so sporadic and able to be easily reset by doing a main power cycle (battery kill switch), I guess erasing volatile memory, that I didn’t worry about it too much (boating seasons are short and competent diagnostic techs few and far between). However, it starting popping every time I used the boat at end of last season. You could feel a slight miss right before the check engine light and limp mode would pop.

Fast forward to this season, and the problem is there with a vengeance. Can’t go more than a few hundred yards without it popping. When out last weekend I tried swapping primary O2 sensors bank to bank and the problem didn’t follow the sensor.

I then went to swap in new factory spark plugs, and found what appeared to be a possibly cross threaded plug on the rearmost bank 1 cylinder. I could not thread the new plug in more than halfway, despite no deformation of the plug threads or metal chips. Since the plug threaded in to same depth as the one I took out, I decided to take boat for a spin. Misfires still there. Even worse, upon cutting power to clear the limp mode, the engine would not re-fire at all, just crank crank crank. After getting towed back to marina, and thinking about it for a week, I decided to check engine oil to see if perhaps it was fuel diluted to the point where oil pressure would not build properly, causing the pressure safeguard to prevent firing, and sure enough there was an extra 4qts (!!!) of fuel in the engine oil. I did a full oil change and also chased that spark plug thread with a tap and got the plug to properly seat.

After oil change, engine fired up and ran perfectly on all eight cylinders, causing me to think that maybe the partially threaded plug was the misfire cause the whole time. But after fully warming up, the fault code and misfires came back.

Since my marina does not have a proper scan tool for this engine, I resorted to more wiggle and wiring connector check tests. Pulling the coilpack connectors off while running would cause almost no change in misfires on bank 1, but would very obviously affect the engine running when pulling them on bank 2. So all of bank 1 seems affected with this issue. After letting it idle several minutes, I turned engine off and tried to restart, but it acted as if hydrolocked, and sure enough all bank 1 cylinders were filled with raw fuel. Pulling all plugs and cycling the starter cleared them and then engine fired back up.

So that’s where I am now. No scan tool in hand (yet), and no service date commitment from any of the local diagnostic techs. So I’m on my own and the season clock is ticking.

Anything ring a bell here to give me a head start on troubleshooting? Are injectors known to fail and hang open on these engines? They are $250 each (way overpriced like all boat parts), so I’m not keen to just throw parts at this issue.

Thanks in advance, sorry for the long winded post. Boat is an hour away, so I have limited window each time I’m there to try stuff.

TD

 

Just off the top of my head it sounds like the ECU is reading the fuel mixture as WAAAAY off and then trying to dump fuel into the offending cylinders to make up for what it perceives as a lack of fuel. Of course figuring out why this is the case, another story. You said that swapping the 02 sensors didn't change anything, which doesn't rule out that they're both bad. So if it was me, I would go get a new 02 sensor, toss it on bank 1, and see what happens. I would definitely change the oil before I started it back up. Where are you located?


Here's the relevant info for those LY6 Injectors: I just found a new set of 8 for like 125. Not sure exactly what one you have in your boat of course.
Fuel Injector Part Number 12580681
Fuel Injector Flow 29.6 lb./hr. @ 58 psi
Flex Fuel Capable No
Fuel Injector Length Between O-Rings 1.900 in.
Fuel Injector Connector EV6 / USCAR

 

Make sure your harness is grounded well, especially the coilpack harness. If all of bank 1 is affected, I personally would start with the bank 1 coilpack grounds. Try swapping some coilpacks around as you did with the O2 sensors and see if the problem follows... As mentioned that scanner will be of great help to know what information the ECU is dealing with.

 

If both were bad, I should have been seeing a fault code for Bank 2 as well as Bank 1. I've only seen codes for Bank 1.

Not sure when closed loop happens with these sensors, as they seem to be wideband, but the fact that it runs well until warmed up fully would suggest a bad O2 sensor as long as there is an open loop period. I suppose a scan tool would show me sensor voltage and how it is reacting during warm-up and then into the misfire stage.

A single primary sensor is an astonishing $309. Total rip-off. I'm not keen on trying to splice in a generic one, as I'm trying to minimize variables here.

Boat is located on the Upper Chesapeake in MD.


Given the load profile of a boat engine vs a car engine, I'm not sure I would count on them being the same (duty cycle rating). I'll see if I can uncover a part number under the Volvo Penta red paint.

An example of the rip-off mark-up on boat parts is that the spark plugs have an Autolite part number embossed on them. Buy that same exact part number in a Volvo Penta branded box and it costs 50% more!

Thanks for the reply.

 

Yup, absolutely a huge boat tax. Good luck man! Like mentioned too, for sure check those grounds. Salt Water corrodes damn near everything even things its not supposed too.

 

Yep, noted about the grounds. Have to physically trace where they are, there are no engine harness wiring manuals for boats, either...

Luckily I am up way north on the Chesapeake, and in basically freshwater, so corrosion is minimal.

I also just bit the bullet and bought the $750 proprietary scan (scam?) tool. Diagnostic Techs keep ghosting me, marine world is the Wild Wild West.

 

That motor is an L96. Does it have an OBDII connector to hook up a Tech-2 or adapter to talk to your phone?

The cross threaded plug, if leaking air, will throw off that entire bank. It may require removing the head to install a heli-coil if the threads are ruined. There are probably ingenious ways to heli-coil the threads without removing the head.

 

No OBDII shaped plug, the diagnostic plug is a flat 6 pin jobbie. All info I have online points only to a proprietary scan tool which will interface, made by Rinda.

Just curious how you know it is an L96? Trying to educate myself on LS engines.

The plug, if cross threaded, is fully seated now, I visually verified. Plus, no escaping combustion sounds at all.

 

Read some literature online and saw the intake manifold, same as on my truck. If it is an L96, it'll have the FlexFuel sized injectors, if not, it'll be an LY6, that's the difference between the two in trucks.

The literature mentioned catalysts, if so, it'll have 2 and probably 4 oxygen sensors. One in front of each cat and one behind each cat. Does it run a speed density system or mass airflow sensor?

 

https://poweredsolutions.gm.com/products/l96-engine/

https://marineenginedepot.com/new-60...ine-long-block

Follow the coil pack harness on the R hand side (water pump is front of engine) and see if one of the wires from the harness attaches to a single grounding bolt on the rear face of the head. If it's there remove or check for corrosion. That is the first place my GM tech said to always check first for misfires - bad ground.

As stated earlier I would also pull every coil pack wire and check for corrosion. You might be surprised to find some of the leads completely corroded and nearly dust.

 

Speed density with four O2 sensors. The injectors are short little guys.

 

Yep. That’s the engine, L96 it is.

There is a major ground point on the back of the “driver side in a car” head (port side on my boat). I did plan to disassemble and clean it next time at the boat, but it already looks pretty clean, as well as all the harness connectors on the engine (plastic is still very pliable and not dried out at all). The batteries ground out to the same spot and I’ve haven’t had any charging issues, but easy enough to clean up the connections there either way.

 

Any way to tell what ECM is used to control this?
$750 for a scanner is insane, for that kinda money just to diagnose it I would have just bought a Holley Terminator stand alone unit for $1300 and ditched all the "volvo" crap as long as the rest of the outdrive is mechanical and not controlled by the ECM.

 

This chart is handy AF.





There's a guy in Maryland who has done on water tuning on Holley systems on boats. His name is Joe Simpson and he owns Tempest Racing. Definitely wouldn't be cheap, but at least then you're back to an automotive setup and ditch all that boat stuff.

 

If the engine has been misfiring and has been running rich I'd guess that you have killed at least one O2 sensor.

It easy to tell which cylinder is misfiring. Get a reasonably inexpensive temp gun at Harbor Freight. It only takes a few seconds to see which exhaust outlet remains cold after you get it started. Shoot the beam at # 7 first. Rear most driver side. It's usually the bad actor.

When you pull each coil pack wire check each pin. Those tiny pins can bend easily and not seat correctly on the female side of the connector.

Check the TSP as well and throttle control sensor and pedal control . If all three don't sync and one of them fail it can set limp mode. With so much chance of water from feet and wet shoes near the pedal IMO that sensor could easily become corroded.

 

I'd have thought that, too, but the code doesn't follow when I swap sensor bank to bank. I have a brand new primary sensor now, maybe I'll just bite the bullet and install it (and officially start the process of throwing parts at the problem).


The exhaust manifolds on a boat are water-jacketed, so it's not so easy to get a clear reading on individual exhaust outlet temps.

When you say 7 is the bad actor, what is the typical root cause? Rear most driver side would also correlate with the spark plug that seemed cross threaded.


Will take a look, but the issue was there even before I started pulling connectors (not saying that me pulling those plugs may not have made things worse).


No throttle foot pedal on a boat, it's all controlled by a hand-operated throttle lever, which in turn moves a cable, which in turn translates cable position to a digital signal for the throttle body, all under cover in the engine compartment. Some boats are full drive by wire from the lever, but mine isn't.

 

Dah - should have remembered the water jackets on my 460 Jet Boat. Sure wish I had kept it. It was blast. Unlike yours throttle pedal was foot operated.

As for misfires I don't remember the source, but it was suggested to always check #7 first for misfire. It was #7 in my case. I would start with that spark plug first, I finally resolved the issue on myTSP 370 by replacing the driver side coil harness. But it is a 98 Z28 and over 20 years old so the electrical wire was getting brittle. That said, every misfire fix I found mentioned checking every ground especially the one on the rear of the head.

As for fresh water corrosion,, it can find it's way into places you wouldn't think could get contaminated with water. I never did find the source of water contamination and corrosion inside the starter on the 460. How or why it even could start to get me out on the lake, but it started and then failed in the middle of the lake. Just about everything in the starter was disintegrated to near powder. I don't know or understand the theory, but it was explained to me that heat creates condensation. You might have to test every sensor to find the culprit.

 

So today was the first time I could make it back down to the boat since posting here. Came armed with the factory scan tool and another oil change kit. I was able to score an appointment with the local Volvo Penta dealer at the last minute, so my plan was to fix anything possible in the morning, and then pull the boat and trailer it to the dealer by early afternoon if I wasn’t successful.

After another oil change, this time with 1/2 qt of fuel in the oil from the 10 minutes I ran it last time, it fired right up on all eight cylinders. Watching with the scan tool, I could see BOTH banks begin to adjust short term fuel trim once O2 sensors warmed up to a closed loop state. Both primary sensors trimmed exactly at the same rate and as soon as -30 trim was hit, the check engine light and alarm would sound. Codes for closed loop trim would then be set for both banks. So my mobile app was not telling me the whole story and sent me off on a tangent. Pulling coil packs connectors and not seeing a change on Bank 1 must have been because of the fuel saturation that was already happening to the plugs.

I cleaned all grounds I could access, none were corroded, checked connectors on all sensors that both banks would share, and also swapped in a new O2 sensor just to make sure that maybe both old ones weren’t fouled and misbehaving the same way (the new sensor mirrored the other one, so scratch that).

By that time, I decided to call it a day and let the dealer deal with it. Hoping they don’t drag their feet, as now I’m at their mercy with the boat there, instead of having a mobile mechanic come to me (three ghosted me).

I’m beginning to think I might have bad injectors on both banks, that maybe they corroded up over the winter from non-use, and they are stuck open. I can’t think of anything else, besides a ground or ECU driver issue, that could pump that much raw fuel in such a short time. Even a fuel regulator over-pressurization shouldn’t allow such high volumes to be squirted on a normal injector duty cycle.

Guess I’ll find out soon. Could have grabbed more data with the tool, but it would have just loaded the oil with more fuel and at the end of the day I didn’t have spare parts on hand to throw at it. Better to not let the schedule opening get away from me.