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halfsack82 said:
Leads me to believe it’s not voltage related
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I think you may have overlooked the subtlety of unanticipated system voltage spikes exceeding 150 volts while jump starting (jump starting is aka: a battery event) in some cases. If exposed even for a millisecond, unprotected semiconductor devices are susceptible to damage.

Take your everyday LM7805 5Vdc regulator IC for instance. The data sheet for this device specifies a maximum operating input voltage of 35V, so anything over is liable to damage this device.
 
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halfsack82 said:
Boat has never been jumped off, battery was just replaced.
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Right, that was the question.

FWIW, I was jump starting a boat last week and this was a concern for me at the time b/c their battery was completely flat and I could tell there was a heavy load on my alternator while attempting to place an initial charge on their battery b/c my alternator was dragging down my engine idle speed as I connected to their battery. Stupid me, I should have connected the cables 1st before firing up my engine due to risk of creating alternator spikes. Fortunately, no immediate harm was done to either boat and it remains to be seen if any damage resulted (perhaps not) but this is a practice that can damage sensitive electronics.
 
Just to clear up any circut voltage confusion, I've designed and built custom circuits for my job at a bio tech company. I have some experience dealing with multiple smaller solenoid valves that caused voltage instability and spikes. On one of my solenoid circuits, I had to integrate control signal for specialized pumps that needed to be extremely precise and consistent. It was critical they were completely isolated and not affected by any voltage fluctuations on any part of the circuit, which I spent considerable time getting around issues. Typically inductors or solenoids would cause voltage drops or spikes, but shouldn't be as serious as @Sportster-2001-951C-Stock is talking about in this situation. A well designed circuit would integrate circuit designs to reduce the severity of voltage drops and spikes. When a starter solenoid turns on and energized, it tries to pull significantly more power than the battery can output, at any given moment, causing the overall voltage on the circuit to drop or even become negative. The voltage spike is caused by the solenoid being d-energized and releasing that energy it used to create a magnetic field, back to electrical energy. Without a proper circuit design, a small solenoid could easily output an excess of 400V, but that was the limit of my oscilloscope for my circuit. With some basic circuit protection effort, it should drop significantly and still last a brief moment to not cause issues to the rest of the circuit. Unless you have ICs that a sensitive and delicate, and use data lines to communicate, such as an ECM, those are a bit harder to protect against voltage fluctuations and still able to function, making them susceptible to be damaged. If under voltage or over voltage was that big of an issue, aftermarket sound systems would cause extensive problems. If I push my 800W amp to 70% power, powering it with 2x deep cranking batteries with a battery tender connected, voltage on my accessory circuit is fine with just vocals. But once the bass kicks and my single 10" sub is going, it will immediately cause a voltage drop from 14.4V to 12.8V. I measured that using a digital voltmeter/dual usb charger unit I swapped my dashboard 12V outlet for. Haven't had time to connect my oscilloscope to it to get an accurate analysis or better view of what's happening, but I would expect to see greater voltage drops than my voltmeter is indicating, albeit briefly. Likewise, I would also see a few instances of voltage spikes, with durations of those spikes based upon the signal frequency going to the sub. In that situation, with under voltage a big deal, it'd damage my electrical system. In reality, I don't have any issues as do most people with aftermarket sound systems with significantly more power.

Since one of his engines turns over still, the solenoid is working fine. If it there was some under voltage scenario, there wouldn't be enough voltage to initially engage the solenoid or it would behave abnormal, such as very slow to engage with weaker actuating force. Additionally, even though yes, small ICs or any component exposed to high voltage for a split second can be damaged, it kinda factors down to power delivery. If it is less than millisecond, not much power was delivered to cause serious problems. To protect against basic voltage spikes, can use a combination of diodes to isolate components and ensure voltage isn't reversed if the circuit's voltage potential momentarily flips. You'd also utilizie capacitors to stabilize the voltage by either acting like a damper against voltage spikes to drop the intensity of the voltage spike or rapidly supply a large amount of energy into the circuit when voltage drops to bring it back up to target voltage. Everything put together, you isolate critical systems and also drastically reduce the min and max voltage of the spike stabilize to acceptable levels. You can go further and include a voltage smoothing component. There's more to circuits than just basic voltage, as changes in signal frequencies and waveforms make a difference. If someone wanted to rule out the starter solenoid, using a voltmeter and turning it on should suffice. If the voltage drops, it's working, otherwise it isn't.

Looking at the LM7805 5Vdc regulator, the input range is 7-35V. The typical use case is someone connecting a 12V power supply or using a battery pack composed of 1.5V batteries in series with a total voltage that's some multiple of 1.5V. Besides the common 9V or 24V power supplies, those are below the 35V operating limit. That 35V limit is usually a performance limit for that regulator to function at and still output 5V. Yes, if you put in a sustained higher voltage, it most likely wont output 5V as consistently when the input is between 7-35V and defeat the purpose of it. If you used that in a circuit with a solenoid with voltage spikes, you'd incorporate a basic voltage protection circuit designs to ensure spikes up don't exceed 35V. Even if you go higher, it's still a brief and doubt it'd cause problems. The only likely outcome is that instead of 5V on the output, given a 50V input spike, it may just as briefly increase output by a bit to like 5.1V, requiring an oscilloscope to properly detect that. What does damage components easily is heat. If a spike lasts too long, or you exceed the 1.5A limit with the LM7805, that can damage it. You could probably put in 40V with a single 5V RGB LED on the output that would draw such little current, you're not really getting close to the thermal limit and it'd be fine.

Regarding jump starting, it's a bad idea to connect jumper cables to a marine battery with all the ignition cables still connected. When you're jump starting, you will be outputting higher voltages for longer time to everything that is connected to the battery, which can be easily overwhelmed and not meant to protect against that. Even with newer cars with extensive electrical equipment ( such as BMW, Mercedes, or Porsche), if you need to jump start them, you connect jumper cables to designated connecting points that make sure no voltage fluctuations are transferred to all the computer systems directly connected to the battery.

But as @halfsack82 said, he never jumped the boat so unlikeIy ECM or other electrical systems would be damaged, unless some physical cut or degradation of the wiring harness. I would definitely agree with @JPass and likely sounds like an issue with the ignition system. Sorry if this is a go to solution, but did you check your spark plugs or replace them recently to make sure they weren't fouled? You mentioned you pulled your boat out of storage and not sure how long you had it in there or last time service was performed.
 
Boat has been winterized and stored properly, it baffles me I’ve swapped coils,fuel lines, ecu, mpem and has new plugs, no change. I’ll have my candoo pro shortly hopefully it will help me out.
 
The voltage across an inductive coil is given as V= L(di/dt) where L is inductance in Henry's, change of current di can be high in hundreds of amps and length of time dt, a real killer, can be very small, approaching zero.

Simply plug your numbers in and you can plainly calculate potential to produce an overvoltage event, there's no magic or voo-doo involved, just fact and explains to large degree why an MPEM is prone to failure while jump starting and other battery events.

I didn't overstate anything.
 
halfsack82 said:
Boat has been winterized and stored properly, it baffles me I’ve swapped coils,fuel lines, ecu, mpem and has new plugs, no change. I’ll have my candoo pro shortly hopefully it will help me out.
Click to expand...

Your engine controller would need a signal from the crankshaft position sensor to time the ignition spark. Without this, no fire.
 
All but the 1st, which is high idle.

The TPS high fault might be causing flood mode.

With several sensor faults occurring, could be a common harness connector issue. A wiring diagram would help determine commonality.

If there's a sensor value page, you can watch the TPS value while operating the throttle, the value should change accordingly with throttle position. Compare both sides as well.
 
Swapped injectors and now the non running engine is running and the engine that was running is not, ordered the x chargers with 42# injectors. Should be good to go
 
Sportster-2001-951C-Stock said:
The voltage across an inductive coil is given as V= L(di/dt) where L is inductance in Henry's, change of current di can be high in hundreds of amps and length of time dt, a real killer, can be very small, approaching zero.

Simply plug your numbers in and you can plainly calculate potential to produce an overvoltage event, there's no magic or voo-doo involved, just fact and explains to large degree why an MPEM is prone to failure while jump starting and other battery events.

I didn't overstate anything.
Click to expand...


I didnt mean to imply you overstated anything. Yes, what you said is true, but that's looking purely at an inductor, which i'm familiar with all the equations for. The issue is, when looking at the starter solenoid over voltage isn't so much a big deal because it's on a circuit that drastically minimizes that event to the rest of the circuit. But with a starter solenoid, that protection circuit is connected directly to it and mitigates the voltage spike coming off the solenoid. There is no need to incorporate a protection circuit on every single component, unless you anticiapte a voltage spike at every single one. When jump starting, you're creating a voltage spike at a point in the circuit it wasn't expected to create on its own, thereby having no protection against it to begin with. Again, when you're talking about data lines instead of power lines, then yes, data lines are very easy to damage. All i was trying to point out wasn't really a voltage spike being the problem. And if the harness got cut up or damages, it's most like to short or damage something that then opens the circuit.
 
anthonymsaad said:
I'm thinking if the injector is clogged and can't spray in fuel so that even with a spark, there's nothing to ignite.
Click to expand...

I think rcookr1 is referring to the OP's original claims of having all but spark when he first presented the problem.
 
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