Help with posible IAC Value

[captain zac]

2001 6.2 MPI BIII

After running all day I was going to dock
Bumping in and out of gear forward and reverse the engine wanted to cut out and then it would rev up
Parked the boat and got the trailer started the boat and no problems loading problem went away (but I am sure it will return unless addressed)
I have clean fuel and fuel separator
I am leaning towards the IAC Valve (never been changed on this boat)
My question is does the IAC valve just die or can it be intermittent?
Is this where you would start or am I looking in the wrong place

Harry

 

[Brew2]

Re: Help with posible IAC Value

Noticed no one had replied, so figured I'd at least bump you back to the top. I too am curious about your AIC valve question. If I had to guess, I'd say the valve either works or it doesn't....can't imagine it working intermittently.

You might want to try removing the AIC valve and checking it for carbon. Had an idle problem with my 5.0 a while ago and when I removed the AIC valve discovered that it was so carboned up that even when the valve was open, the hole the air was supposed to flow through was completely blocked. Took and old toothbrush, cleaned it up, and the idle improved greatly.

Good luck!

 

[captain zac]

Re: Help with posible IAC Value

Thanks

talked to a guy that said there was a small foam piece in it also that sometimes gets sucked into the engine
said it would not hurt the engine but would need to be replaced.
do you remember seeing something like this when you cleaned yours?
I am going to take a look on friday

Harry

 

[captain zac]

Re: Help with posible IAC Value

Just checked it called the IAC muffler

 

[emilsr]

Re: Help with posible IAC Value

Thanks

talked to a guy that said there was a small foam piece in it also that sometimes gets sucked into the engine
said it would not hurt the engine but would need to be replaced.
do you remember seeing something like this when you cleaned yours?
I am going to take a look on friday

Harry

There is a foam piece (called a muffler).

Normally a bad IAC will set off a soft alarm in guardian; 2 short beeps every minute and a 10% reduction in power. Is your engine equipped with Smartcraft? If so, I'd have it scanned to make sure that is the problem before you throw any parts at it. I don't know about your 6.2, but it's a $100 part on my 496.

 

[wifisher]

Re: Help with posible IAC Value

I have no experience with the IAC on boats, but on autos they can be intermittent. I would think boat motors are about the same in this regard. They act in the same way you are describing. With a scan tool (on autos) you can test it by commanding the position to move up or down.

 

[Brew2]

Re: Help with posible IAC Value

Yup, familiar with the "muffler" as well.

The muffler on mine also had some carbon build up, so I replaced when I cleaned the valve up. The muffler isn't actually part of the AIC Valve itself....if I remember correctly, it was in a recessed cavity on the inside of the throttle body. The muffler is only a piece of foam about and inch square by 1/2 inch deep....friction fits into the recess.