DF225 Eating IAC Valves

[chrisorbesen]

New member here. Thank you for the Forum!! My 2005 DF 225 has gone through two IAC Valves. I was out yesterday and again at low idle, it started running rough and would not accelerate. Once I would take the throttle back to neutral and accelerate down quickly the boat would respond correctly and take off. As we approach the dock and go to a low idle, the alarm will beep single beeps every 7 seconds approx. I have replaced one ECU (top one) already as I did have a charging issue, but that has been resolved unless the beeps are telling me that is an issue again? Could I have two problems?

Thanks

[catacom225]

Chris, Have you checked resistance on the valves replaced and confirmed their dead, accelerating down quickly on a bad IAC would have a stalling effect. I think a series of single beeps may be a low voltage alarm, firstly check all 12v connections are clean and tight and battery volts is at 12v

[chrisorbesen]

I believe you are correct on the alarm. Out at the boat today and the beeping stopped BUTTTT I have water poring out of the exhaust port under the cowling. This has never happened before, they cant be related right?

What causes this water out the exhaust and not out the prop. My pisser looks great, just did the 500hr service a month ago, replaced the IAC valve again as well as the upper rectifier. Should I be replacing the liwer rectifier as well?

Thanks

CO

[Keysspear1]

I am by no means a mechanic. But I recently read that a bad thermostat can allow too much water flow basically allowing it to be pushed out of the exhaust. Is it possible the rough idle was a result of the thermostat not allowing the cooling correctly and the motor was preventing an overheat but you may not have gotten the gradient temp warning? Just a thought.

[Keysspear1]

Was just searching for the article. It wasn’t an article, it was a video on born again boating that explained it. Easy to find with a quick google search.

[chrisorbesen]

Thank you I will look it up. I plan on getting into the thermostats in the next few days. I had just completed my 500hr maint. and replaced them both, but who knows if one of my kids sucked up a bunch of sand and has one sticking open.

[Keysspear1]

No problem. Hope it helps. I added the link the video. Sorry I didn’t do it last night, couldn’t get it working.

https://youtu.be/OeCNF6IFf1Y

[hanksboat]

Hope you don't mind me piggy-backing on your thread - but I have a 2004 225 (Johnzuki) that only starts with throttle and shuts down when decelerating from plane. It all pointed to IAC. When I unbolted the IAC, the manual says that when turning the key ON it should open and OFF it should close. My IAC did nothing when going from OFF to ON and back to OFF. I installed a new ebay IAC today but it also isn't moving by turning the key. I have continuity between all wires from IAC to ECM. Am I missing something?

[chrisorbesen]

I have purchased one IAC from auto parts store. Same IAC as the Suzuki Vehicle. That was 150.00

I also purchased this brand for only 31.00 and it worked perfect for awhile then failed again. I ordered two more because they are so cheap.

Big question is WHY ARE THEY FAILING?

2 of AUTEX 1pc Idle Air Control Valve IAC IACV 1813752D00 18137-52D00 2H1312 AC508 2167936 AC4218 compatible with Suzuki Grand Vitara XL-7 2001/Suzuki XL-7 2002 2003 2004 2005 2006
Sold by: PartsSquare
$31.84

[hanksboat]

ok - nevermind. The new $18 valve worked. The engine started without touching the throttle. Then, I took the IAC back out and it does in fact open and close. I bought 2 just in case this one craps the bed. I will say I have a good feeling all of these valves under $50 from Rock Auto, ebay, or amazon all come out the same factory in China. Just a hunch - that's why I got the cheapest one I could find.

[chrisorbesen]

I still have not heard from anyone as to why these IAC valves go bad so quickly or what causes them to go bad.

CO

[Keysspear1]

I went through a similar issue. Kept having the rough idle sometimes a code, sometimes not. Changed the IAC several times. Despite several recommendations to test it, I was surprised to find out it truly wasn’t the IAC. It wasn’t till I finally hooked it up to the diagnostic that I realized it was functioning properly. That’s when I discovered the thermostat issue. Turned out I was getting that rough idle due to a gradient over heat. The motor sputtered and shut down, unless I gave it throttle, in order to prevent overheat. I wasn’t getting consistent codes on the old system monitor. Found the thermostat was stuck open changed it and never messed with an IAC again. This may not be your issue, but if you haven’t, I’d suggest testing the IAC or checking the motor on the diagnostics to ensure that’s the problem. Good luck hope you find the issue!

[redlowrey]

I still have not heard from anyone as to why these IAC valves go bad so quickly or what causes them to go bad.

CO

How does 31$ sound, in your first post you say the engine would not accelerate when the throttle was opened, nothing to do with the iac valve.

[redlowrey]

I went through a similar issue. Kept having the rough idle sometimes a code, sometimes not. Changed the IAC several times. Despite several recommendations to test it, I was surprised to find out it truly wasn’t the IAC. It wasn’t till I finally hooked it up to the diagnostic that I realized it was functioning properly. That’s when I discovered the thermostat issue. Turned out I was getting that rough idle due to a gradient over heat. The motor sputtered and shut down, unless I gave it throttle, in order to prevent overheat. I wasn’t getting consistent codes on the old system monitor. Found the thermostat was stuck open changed it and never messed with an IAC again. This may not be your issue, but if you haven’t, I’d suggest testing the IAC or checking the motor on the diagnostics to ensure that’s the problem. Good luck hope you find the issue!

Unless you had an idle problem when you started the engine red hot, stuck open thermostats would have absolutely nothing to do with an iac valve.

[chrisorbesen]

no two separate problems on same motor