Decelereration stall and no start

[pepmyster]

Hi guys, We bought a new to us 2004 360 Sports Sedan with VP 8.1's. Engines run very well, this problem happened 3 times, while underway, when I come down from cruising to idle the engines, the Starboard engine quits. I would turn off the key, turn it on again, I would not even get the 2 beep okay to start. I have to wait some time before that would happen. All of a sudden, the 2 beeps come on, start the motor, then continue. Like I said, if we are just trolling, no problem, it seems to only happen after cruising speed. Any thoughts?
Thanks, Andrew

[Viper]

Can you post the engine serial number?

[pepmyster]

I have the numbers at home, I will post tonight.
Thanks
Andrew

[pepmyster]

Port engine 4012121383
Starboard 4012121384

Thanks
Andrew

[Viper]

I ran the numbers and nothing is standing out. There was a warranty job on one engine for an oil leak some time ago but there are no outstanding campaigns.

The best thing to do would be to get it hooked up to a diagnostic tool and check sensor reading when this happens in real time to see if one of them goes out of range. It could be a number of things but the simple ones that come to mind are the IAC and perhaps the TPS. Something could also be causing her to overfuel when you throttle back.

When she stalls, what happens if you try to start her without waiting for the beeps? Will she crank over, will she try to fire?

[pepmyster]

Thank you for running the numbers. I suspect also the IAC.
Looking at engine, the plugs are original. Cannot believe 750 hours on plugs. Going to change them next weekend. Also , I believe, it would be a good thing to change IAC on both engines since it’s a wear part. The flame arrestors aredirty also.

[pepmyster]

Also, cranking the engine produces no spark.

[Viper]

Source of the post Also, cranking the engine produces no spark.

You mean right after it stalls? If that's the case, it takes us in a particular direction.

[pepmyster]

Sorry for the multiple replies. Yes after it stalls, if I turn off the key, to try to restart, I will not get the double beep . If I try to start it anyway, it turns over but not start. If you wait a while, turn the key, if you hear the beeps, then okay. I asked the marina here if they had the diag tool for VP, they don't.

[Viper]

Again, it could be a number of things but if you get no spark when this occurs, then it's likely an ignition issue, and may even be more that one system fault. I'd be curious to know if the CPU is getting a crank or cam position signal when that happens. I had similar symptoms on a boat that first ran fine, then would stall intermittently and not restart for a few minutes after. Eventually the engine wouldn't re-start at all. The culprit was a bad crank sensor. I don't recall if yours has both a crank and cam sensors but I can look it up. If It's an intermittent sensor and the CPU can't tell what position the crank is in, it worn't fire. Of course the obvious applies here as well such as ensuring there are no wires grounding out, good tight connections, and harness plug contacts free from corrosion.

Is the marina a Volvo dealer? They won't have the Vodia diagnostic gear or proper manuals if they aren't. Without those, they'll just have to use their heads and systematically go through a diagnostic process to arrive at a proper conclusion, otherwise I can see this spiraling out of control ($$$) as they throw darts (new parts) at it in hopes that one will solve the problem. If they're not a dealer and they get OEM (Volvo) parts, they won't get them at cost and will charge you more than they would otherwise cost from an OEM dealer which is where they would likely get them from at retail or trade cost (not dealer cost) then mark it up again so they make money too. Unless they are very competent and the fault is obvious, I'd be looking for a marina that is a Volvo dealer with the proper diagnostic equipment that you can run your boat to.

On another note, if you're handy with tools, have some mechanical knowledge, and feel comfortable enough to tackle this yourself, the good thing about having two engines is that you can swap suspected parts to see if the problem follows the part. You must only do this one part at a time though or you won't know which part solved the problem.