chaos4all

Hi all, after much work today and allot of searches on here, I think I have narrowed down my problem on my merc 496, possibly. I am new to working on my boat so forgive me if I mess this up. My impeller burned up and was replaced today, but the boat is still doing the 2 beeps and later the one long beep going into Guardian mode. When hooked up to the computer no faults are found. After much research on here it seems that the IAC and possibly and exhaust manifold sensor has gone bad. This seems to be the info I am finding when this happens but the computer reads no faults. Does this seem like an accurate conclusion? If so I called Merc and they say it will be July 17th or later to order an IAC. I looked at BAM to order and see if they have stock, but are these the correct part numbers for a Merc 496?
IAC 862998
IAC Gasket 27-863112
Exhaust Sensor 889575

Thanks for any help offered,
Craig

Dave_N

What your saying happened (Guardian mode activated with no stored code) shouldn't happen unless the PCM is bad. So I hope your mistaken.

What active faults were showing when it was scanned? Were there any inactive faults? What faults were in the Freezeframe memory?

Dave

chaos4all

I will check with the tech who ran the scan but he said there were no codes. Now I am taking his word for it and maybe he doesn't have a clue. They are a Merc certified shop so I would think that he would. Now if the IAC is bad would that show a code? I thought that I read that it wouldn't but it would cause the Guardian mode. I thought that I read the IAC diagnostic does not work correctly for some reason?
It all started when I was coming in about 5 weeks ago. I went out fine, anchored, and had a good time, started back up and the 2 beeps and the continuous alarm sounded with cut of power. When inspected the impeller was burned out but not fragmented. Impeller was replaced but the 2 beeps and guardian still happen. The thec claims no codes are found. That is why I started looking on here for solutions. All fluids are full and it only has 54 hours on it. Thanks Dave for your help, any suggestions is greatly appreciated.

Dave_N

An IAC failure will usually set a IAC fault, but not always. Any fault that sets an alarm should be recorded in the freezframe memory. Is there any way you can get the fault history from your tech and post it?

Dave

chaos4all

I talked to the tech yesterday and he said there were no faults showing other than the normal chris kraft faults, that don't mean anything. (i think that is what he said) I asked about the freezeframe and if he could send me that.He said he didn't see anything there either but if he had time today he would try and e-mail it to me.

carney

You said your impeller burned up. Did you back flush the hoses and find most of the pieces. lots of people put in new impeller's and leave pieces behind. As for your IAC I can not help. good luck

chaos4all

Thanks for asking but the impeller was fried but it didn't fragment, so I don't believe it needs to be flushed? It is all in one piece. Does anyone know if the above are the correct part numbers if I decide to order them.

Thanks
craig

Pwrbt33

iTrader: (2)

The exhaust sensor I guess you meen the temp sensor in the manifold? If so, I come up with 858535. You may have the superceded number though. All the other numbers look good. You may also want to get the lower gasket just in case it was to rip when you take the other off. That number is 27-863285. Good luck.

John