GT40 EFI Idle Control valve

[rossl]

hi all,

Our 1996 Super Sport Nautique with GT40 EFI, surges at idle from 600 to 1200rpm about 30% of the time, i took of the idle control valve and cleaned it out and it is now a bit better but still does it about 15% of the time, can i just disconnect it and set the idle manually with the butteryfly stop screw? do I need an idle control valve, as it seems to be more useful for cars with aircon etc?

Cheers
rossl

[Rick]

RE: GT40 EFI Idle Control valve

No the idle control valve is connected to the computer in an open control loop. It still responds to the knock and temperature sensors. disconnecting it I beleive will foul up that loop.

[rossl]

RE: GT40 EFI Idle Control valve

Anybody know a part number for the IAC Valve as the boat is not near and i will take a new one up at the weekend if i can get one in time.

rossl

[1999Sport]

RE: GT40 EFI Idle Control valve

I replaced mine a few months ago...I have the spare laying around...I can check the part when I get back at home...you should be able to look up a part for a 90's F150...should match right up...

[richard]

GT40 EFI Idle Control valve

will your boat hard to start when engine is hot?

[rossl]

RE: GT40 EFI Idle Control valve

starts straight away when hot , takes a couple of tries when cold.

[richard]

GT40 EFI Idle Control valve

Had experienced the same hot engine hard start propblem,plus rough idle and engine stop when shift to neutral,engine is GT-40 EFI,after exam many parts include Idle Control valve ,figured it out caused by a bad fuel pressure regulator.

[vortech347]

RE: GT40 EFI Idle Control valve

I've had the same problem from day one with my 99 Sport. I had the dealer look at it a couple times under warranty and they could not duplicate the problem. I wound up replacing the IAC as well and cross referenced the part number with a 93 Thunderbird 5.0 liter engine. Changing the IAC helped some but it did not fix it completely. I'm going to try the fuel regulator next.

[1999Sport]

RE: GT40 EFI Idle Control valve

Here is the part number that is imprinted on the part that I took directly off my motor...

E9SE-9F715-EB

[rossl]

RE: GT40 EFI Idle Control valve

thanks a lot

[2ndhandwake]

RE: GT40 EFI Idle Control valve

Did you get your problem fixed? I just bought 1997 super sport and I am having the exact same issue. Engine surges in nutral to about 1200 rpm.

[rossl]

RE: GT40 EFI Idle Control valve

Yep fixed, it was not the idle control valve, it was the little valve/sensor on top of the throttle body (about the size of a coin with 2 screws either side), just up from the ICV, think it some sort of cold start thing, unplugged it and boat idles perfectly.

Rossl

[2ndhandwake]

RE: GT40 EFI Idle Control valve

I will have to take a look at my boat and see if it has something similar. Mine has the multiport injection so I don't know if it will have the same piece on it or not.

[1999Sport]

RE: GT40 EFI Idle Control valve

Two screws up on top should be the TPS (throttle position sensor)...mine went out and the boat wouldn't hold idle unless I revved it and engaging into gear would almost always kill it. They are about $50. This will tell the computer what mode the motor is in and adjust fuel accordingly.

If you have a volt meter make sure that the voltage is linear from 0 to 5 volts. There is a section in the manual you can download from this site that will help with troubleshooting. But in short...easiest way to check this is to do a "key on engine off" test and have someone move the shifter from nuetral all the way to full throttle while you are checking voltage at the TPS...hopefully this helps anyone else with the problem.

Also...the TPS can be adjusted when installing it and will change your idle...as you're not supposed to mess with the idle screw.

It looks like the one on the right:

[brad]

I have a 01 air and it does excatly the same thing between 600-1200 then is fine is there a way to test this sensor