Ilmor 5.7 starts, revs, then dies

[kyfooter]

First time starting it this year...baseball got in the way. Never had an issue before with the boat or engine, so don't want to over think things. Boat was put away fine, winterized properly, has fuel. Keep in mind it isn't even getting up to temperature.

Fires right up, runs for 2-3 seconds, dies. Throttle has no impact on the engine currently. Zero off is off. Lanyard is connected.

[btriantos]

What year? Push to start? Check your lanyard.. pull off completely then on again...


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[kyfooter]

Lanyard is fine. Wouldn’t start if lanyard was off. Boat is a 2013.

200 hours.

[kyfooter]

Here is what the engine does.

[NewName]

Try if your fuel pump keep running when u start the engine, disconnect your throttle plate and all other sensors at your intake manifold.
You need to find out what is missing, electric signal or fuel. With missing sensor Engine should usually run in emergency mode atleast.
While engine running you got your knock sensors, crankshaft sensor and some sensors on the intake. Just try to unplug and see if something changes.

It could also be a dirty or clogged fuel filter unit inside your tank or damaged hose. If you turn the key the fuel pump will run a few seconds before starting the engine. Maybe thats enough time to prime the system but while running it wont supply enough fuel to keep the pressure. This would be my first part to investigate! This could be also the reason why your throttle have no effect due to low fuel anyway.

Air should be fine, ingition seem to work aswell so i would focus in fuel or sensor.

[kyfooter]

Any other thoughts? What would go bad just from sitting while winterized? Ran perfect before winterizing. Fires up immediately, but then shuts off within 4 seconds every time. No sputtering...shuts off like the key turned it off.

[NewName]

Ilmor 5.7 starts, revs, then dies

It depends what you did for winterizing, normally u remove the knock sensors.
That’s why I said check them. Besides that I would bet on fuel. Either pump is clogged or your fuel went pretty bad! How much did u had inside before winterizing?


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[kyfooter]

Yes, knock sensors were removed to drain block, but then replaced and the engine ran again as I sucked up antifreeze and fogged the engine. Same process for over 20 years.

Last step was removing all spark plugs, fogging, then removed coil wire to turn engine over a few times to lubricate the fogging oil.

Gas tank was 3/4 full with stabilizer.

[kyfooter]

Engine is getting fuel and the pressure seems to be holding fine. Over 50 lbs of fuel pressure when priming and while running.

Removed knock sensors and they had no impact on engine starting nor did they stop whatever is causing the engine to turn off.

[NewName]

Ilmor 5.7 starts, revs, then dies

You could also try to remove one spark plug cable and putanother plug outside to see if ignition is working fine or maybe collapse after few seconds.
Like I said before, you have air, fuel u checked, now move to ignition.
MaYbe humidity inside the distributor ?
Did u try to disconnect the throttle plate do get the engine to emergency mode ?



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[kyfooter]

Latest is I can keep the engine running if I move the throttle to about 50% throttle. Note that the engine is still not responding (revving) but it will stay running at about 1,600 rpm. As soon as I pull back to neutral, the engine shuts off.

On separate note, but perhaps related, my stereo will not power up.

I did check the ignition switch and it is working properly.

[kyfooter]

Can a low battery send a boat into limp mode?

I searched the forum and it appears that has been the culprit on a few threads. Wouldn't seem so to me, as once the engine is running the alternator takes over, but figured I would ask.

I did leave the battery in the boat during offseason and I have not charged it. However, the engine is firing right up.

[Elberoth]

With the engine (and alternator) running, your stereo should see a steady 14.4V, even if the battery was low.

[kyfooter]

What about relay switches?

[kyfooter]

Solution - Relay fuse on back of engine was bad. Posting in case others run into this issue. Very easy fix. Pull the black box cover off the engine near the distributor cap and there are 5 relay fuses within.