PQ with 496, might want to save this info
 

[IMG]http://i1266.photobucket.com/albums/...rquest/pq2.jpg[/IMG]Monday after hard weekend of boating, boat starts 2 beep alarm at other end of lake. Checked all fluid levels, narrowed it to Starboard engine. No manuals came with my boat. Found chart on beeps online. Buddy let me use his scanner. IAC code, told to clear code and should be fine.
kept looking, told to look for melted plug to IAC, also noted that the plug was a Motocraft number along with IAC.Re-checked by pulling IAC off. Plug on IAC started to melt, Motocraft part was correct. Sometimes google is handy!
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Constant tone alarms are for:
1.) engine coolant temp overheat,
2.) low engine oil pressure,
3.) engine overspeed,
4.) exhaust manifold cooling temp overheat
5.) sea pump PSI low

Constant beep alarms are for:
1.) low outdrive lube level.

Two Alarm beeps every 60 seconds are for:
1.) Faulty cam,
2.) IAC,
3.) MAP,
4.) MAT,
5.) knock sensors.
6.) open/short in the engine cooling temp circuit
7.) open/short in fuel injector wiring circuit,
8.) open/short in oil PSI circuit,
9.) open/short in exhaust manifold cooling temp circuit,
10.) open/short in sea pump circuit,
11.) open/short in throttle position circuit

You got lucky it didn't melt the plug on the wiring harness. Some have even roached the ECU!

Are the two bolts that hold the IAC down torx or metric? I need to replace mine (330 hours) and my motor is tucked up under the transom lip so I will be doing it blind.

Alan wrench took mine off.

Thanks!

The gasket, if not supplied s/b Motorcraft CG-763. Also, Ford/Motorcraft does sell the harness side connectors...WPT-XXX not sure of this number...Blue Oval can you dig through your Motorcraft catalogue?

Blue Oval...further to the bad IAC be sure to look for the cause. The melted connector is typically a result of high resistance, resistance builds heat, the connector at the IAC was the weakest link. Check the harness connector and all grounds...what could be next...ECU? Make sure the connector seal is in good shape and use some silicone di-electric grease on the terminals.
Knot 4 Me...why would you want to change an IAC that is working? It's an electronic solenoid not much different from a fuel injector. Sometimes they get gummed up from blow-by gases but then just clean the valve portion. How does the boat idle? Does the engine stall out when coming off the throttle?
Just trying to be helpful...not meaning to be a smart-azz.

I've asked myself the same question...why am I considering changing out a perfectly good working part. The boat runs perfect so why mess with it. I keep a new IAC on gasket on the boat in case the IAC begins to act up. I could just wait for the tell-tale symptoms or the two beep warning and then change it out. However, the boat is entering its 8th season of service and has 330 hours on it. Most IAC's on 496's are lucky to go 200 hours. I've seen several posts, this one included, where by the time you get the beeps or the motor starts to not want to run at idle damage may have already occurred to the wiring. That is the only reason I am considering changing it out before it goes bad.

I guess if the IAC's on 496's have a bad track record, and you've ready spent the money then call it preventative maintenance. Just wondering if the valve portion becoming sticky strains the solenoid part??? Most automotive applications have adaptive learned strategies to overcome engine aging issues. Just make sure all your connections and grounds are clean and secure...:drink:

Gasket number F7UZ-9F670-AB, wire kit number is WPT-357, did not check that as for now I don't need it.

Well I read this post serveral times thinking I should change my IAC's And yes I do work at a ford dealer so easy to get the parts right. Well I did not change them, we go out on the lake last week and what happens? An IAC goes out, I get the 3 beeps when I turned on the key on, started up but going to take off the warning beeps 2 times again then at idle the engine stalls out, checked the IAC and found it looking just like the picture.Ran to NAPA to get a new IAC, installed it and fix the problem. Thay crossed the Ford part number. Yes I will do the other engine before I go out again. So if you have a 496 MAG HO replace your IAC'S...

Sorry to hear you had this problem...seems to be a 496 common concern? Does Merc have any recalls or bulletins? At least you caught this before any harness or ECM issues.

Anybody have any insight as to why a Motorcraft part is on a GM engine? I thought Motorcraft was a Ford supplier? Is this a Merc specific change or do all 496's use this IAC (i.e. the engines in the trucks, etc)?

On the 8.1 trucks, they're "fly by wire" so the air is controlled by the throttle position instead of an IAC I'm almost positive. The throttle body on the Merc version is different for sure.

you are correct...

Motorcraft is Ford, the parts retailer just like AC/Delco is to GM.
I hate to assume but here goes...GM used a lot of electronic throttle (drive by wire) bodies with the with IAC function done there...does your 496 have a cable operated throttle? Also GM used stepper motor IACs which could not be 'feathered' as easily like a solenoid during decel.
Hey, it's Merc...why can't anyone seem to find fuel injectors for my 575s...GM TBIs...Merc discontinued the injector and their p/n doesn't cross?


Lots of response while I'm typing. LOL.

Port or Starboard engine, mine was starboard, just curious.

It was the port side I had the concern with.

Anyone have the CORRECT part num for Motorcraft iac valve. Cx1946 is not it. Looking for the EXACT replacement. 496 mag.

I've heard it's the same as the one on a Ford Windstar. I've also heard sometimes the connector is in the wrong position so be careful. Motorcraft CX1766 maybe the right one but don't quote me on it.

It's either that or cx1897 but no pics show the shape of the ports. They are not round.