DF90 to DF140 IAC valve operation

[simon-666]

Does anyone know if i should see the IAC valve physically open if i activate it using the Suzuki SDS software?
Mine just buzzes but no valve movement.

I know the valve is good. It measures 9.9ohms on a meter and will open when i put 12v on the pins.

I thought my ECU was at fault so tried a friends ECU and his does the same.

[celovic]

Iac df90a

Chances are both valves would not be at fault. I am wondering the same, if you reconnect them but have them dismounted they should cycle when you turn the key to on. I have a DF90A and I think I have had a IAC (Mitsubishi) go bad, the symptoms are: wont idle, thus wont start unless neutral throttle is applied. Runs perfectly above idle, after getting it started I got home on WOT. It looks like the IAC vale is the same as Suzuki car, Mitsubishi Pajero, etc etc. They are easy to change, you need an offset Phillips head to get the rear screw out, no need to remove the fly wheel, just the plastic cover. I use the boat in a very salty lake, and I think it ingests a fair of salty vapor, I think that's the reason it failed. I ordered a IAC off ebay for about 100 dollars. We will see. Still they are a cracking engine, light, low skeg print, and low profile.

[redlowrey]

Does anyone know if i should see the IAC valve physically open if i activate it using the Suzuki SDS software?
Mine just buzzes but no valve movement.

I know the valve is good. It measures 9.9ohms on a meter and will open when i put 12v on the pins.

I thought my ECU was at fault so tried a friends ECU and his does the same.

''''' Have you got a problem or you just want to know about the buzzing. The iac valve is just a two wire magnetic plunger type valve, where one side of the valve is supplied with battery voltage and the other side is grounded by the ecu. Depending on requirements the ecu will duty cycle the ground, the higher the idle the longer the ground and vice versa. When you put a ground on it and it retracted is what the ecu will do when you crank the engine 100% duty cycle, then depending on temperature and loads will change the duty cycle.

[Captronjon]

I just changed my DF90A IAC Valve and everything ran well for a day. Now once the motor warms up it idles at 650 rpm's but as I give it throttle it jumps to 3000 rpm's no in between. If I increase the throttle very slowly it will ht a point where it stalls and dies. When in gear it jumps to 3000 rpm's and will not decrease or go into neutral. I have to kill the motor, put it in neutral and then it starts right up. Could this be the new IAC Valve? Perhaps the throttle position sensor? I have the SDS software but it will not communicate with the ECM.

[redlowrey]

Does not sound good, check the resistance of your old iac valve should be between 4 and 8 ohms, if it is zero you have probably fried the internal iac driver in your computer.
Check the resistance of the new one as well.
Disconnect the iac plug and start the motor, you might need to use the warm up leaver, you will soon know if that is your problem.