2 Warning Beeps on 496ho???
 

I plan on having someone run the codes, but I thought I would ask here first. While running the boat this past weekend at Havasu, the boat would emit 2 beeps intermittenly. I initially thought it was drive lube so I topped it off (was still above the ADD line, but was under the Operating Range line). I then thought it may have been oil pressure b/c after a long WOT run, the pressure would drop to around the 10 psi mark (hard to tell the exact numbers on my gauge). But even when starting after 3-4 hours of not running the pressure was back up to around the 40psi mark but the 2 beeps came back.

To keep it in perspective, we ran the boat all day Friday and Saturday and the series of beeps happened around 9-10 times. Everything seemed fine from my vantage point oil pressure and level, temp, drive lube, etc. Does anyone have any insight on this or has had this happen?

Btw, the boat seemed to run just as strong as it did the last few times I have taken it out, just curious about the beeps!

Thanks!

There are a lot of conditions that will trip the engine alarm.

What absolutely baffles me is when people run their engine with an alarm for hours; let alone days.

The fact that it didn't break down on you all that time suggests that it's probably nothing very serious but I don't think it's safe to trust your boat gauges and "carry on".

If the engine never went into guardian mode then you can most likely rule out: exhaust temp, coolant temp, oil pressure & drive oil.

It will only be speculation until you talk to the box.

If it only beeped at idle you could be down on water pressure with extra heat after a run..

The water pressure sensor could have seen a slight drop and came back up etc...

Grab a scanner & good luck!

I thought gear oil, water temp, and oil pressure produced a steady (solid beep) alarm.

SDfever is right, stop guessing and get it scanned.

More than likely you sucked up some garbage in your drive and you have a blocked heat exchanger or passage.

We went through this last year, we ended up with too much water pressure and it set off the alarm. The boat never over heated and ran great, but kept getting the alarm untill we figured it out. They cleaned out the hose first, then the cooler etc... There was almost a dixie cup full of junk by the time it was all said and done. (For us, as soon as it came on plane the buzzer went off, so we had a couple of attempts before we figured it out completely.)

Good luck.

2 things that can cause it on the 496 are a bad idle air control and a bad water pressure sensor. And there may not be any codes set (stupid computer). You need a scanner that can look at the values (Rinda program). If the water pressure reads any at all with the engine off, key on, then you have a bad sensor. If the idle counts are at like 99 with the engine warmed up and running, bad idle air control. If you can't get a good scanner, those are the first things to swap.

Actually, once going on plane, the idle counts stay at 98 to 99 the whole time and this is normal.

If it was the IAC, then he would have been in guardian mode at or above trying to reach 4000 rpm. 4000 is the cap with a bad IAC. That's the sofware limitation.

This is why internet diagnostics is not a real good idea. Get a scanner.

For further clarification, the digital water pressure sensor can and often times will read less than 1 LB (variable) with key on, engine off.

It's also common to see it flucuate with those same parameters.

Well as we can see from the charts below, idle output will give 2 beeps and only limit power to 90%, so it will not be in Guardian Mode nor will it be limited to 4000 rpm. Also idle counts would be monitored at idle, when warm, so 99 would be bad. So discussing what is seen on plane is immaterial.


What you will see in many cases (guess you haven't) is the pressure showing approx. 40 psi with the engine Off, Key on. this will NOT set a code and will set a 2 beep and 90% power, once again, no Guardian mode.


What I was trying to help with (not diagnose) was the next post that he was going to make saying, we scanned it and there were no codes, now what? Check the idle counts at idle, warm. Also check water pressures to see if they change and are reasonable when the engine is running and not.

had the same problem last summer beeping every now and then but still ran great .ended up being the iac motor as you said .they were on national back order then .a dealer on ebay had new 1s listed and i bought both prob solved

It turns out the part is actually a Ford part used on some Lincolns. You can take it to a good auto parts store and they can match it, but the price is about the same as Merc (never heard of that before). But if Merc is backordered it is an option.

Thanks so much for the input guys! I am actually going to run the scanner tomorrow hopefully, but def. before I take it out again in a couple weeks.

And no, it did not go into guardian mode at all.

Ted, this was not a stab at you. It was trying to make the point that internet diagnostics can be dangerous to a guy who doesn't seem very experienced... Or in some cases it's not really dangerous but it can be more costly than usual. With that..

90% IS guardian mode. And I can assure you that when the IAC starts tripping codes (or sometimes not) it will limit the engine to 4000 because I've personally done this twice. I'm sorry to say that this is living proof. We're not even sure if it is in FACT the IAC but assuming it is.... This would be the FIRST increment in guardian mode by reducing power to 90% available.

Further, the IAC on this engine does not act like most all other efi engines. It has a range of duty cycle but if you ever drive the boat around with the scanner hooked up you will see that there are only about two different ranges.. It's either down in the teens to 20% or it's stuck at 99%. Again, this is how the software in the 555 / 496 configuration is coded. It also does weird things with timing. Finally, regarding what ever you see on plane is irrelevant, that's the quickest way to troubleshoot an IAC particularly on a 496 because it locks your power range. Like you, I was only trying to help by possibly preventing a bunch of people from sending him to the parts store while often times finding out that the new part may not have solved the issue.



Yes, I have seen the water pressure max out to the limit of 43PSI with the key on; engine off. But he never mentioned anything about the water flow so that is still kinda wide open. However, once again, if the sensor reduces power by any percentage, it's one of the several different levels of guardian and if you don't have a scan tool handy, trying to run it at higher rpms will tell you but obviously there is risk to that depending on what the issue is.

ALL of the guardian parameters are not on those sheets specifically. Those look like what came with my SmartCraft Gauge and the options will vary from one engine to another.

Strictly from my experience, it gets dang expensive throwing parts at an engine if you're not totally sure. I haven't had to buy one for a long time but I'd bet that particular IAC has jumped up in price by quite a bit.

Not trying to be a "know-it-all". No hard feelings.

:ernaehrung004:

Well, he certainly has a lot to work with now :lolhit:

It's all good as long as he loses his beep:drink: