The IAC valve/High Idle

[Rustang©]

Hey, I wanted to ask y'all a question, i was wondering what the idle of a OHV 4.0.

Currently I have a idle ranging from 950-1000, hot or cold, winter or summer.

I accidentaly disconected the IAC plug whil still in place, i noticed the idel dropped to about 550, i was thinking if i turn up the idle(Turning the butterfly rest screw). I can get the idle to 750 and be happy.

Will this work, and not cause harm?

Thanks

 

[l1k2gadd]

I don't know what the idle is supposed to be but the Haynes Manual says the idle is FACTORY PRESET. There is too much detail in the Haynes Manual to type all that is in there about the IAC. If I have problems with my vehicles that I think the IAC is causing I remove the IAC and clean it. I use PVC pipe cleaner to clean them.

The process is simple but when you remove the IAC you have to be careful not to break the gasket or round-off the screws that hold the motor to the diaphragm assembly. I mark the two sections on one side so I don't put it back together backwards. I soak / wash out the diaphragm assembly a few times with the PVC pipe cleaner and then put the two pieces back together. When the two sections are reconnected you have to be sure the pin moves freely between the two pieces so the IAC opens and closes properly. I then reinstall the IAC and the problem goes away.

The simpler thing to so is buy a new one and see if there is a change in the idle. I'm cheap, I prefer the $2.99 can of PVC pipe cleaner (CLEAR - NO COLOR) to the $30.00 to $60.00 IAC (last time I priced one for a 5.0).

I wouldn't recommend leaving it unplugged for any reason.

 

[Rustang©]

Thanks man, i did clean it out once before, i used carb and di electric cleaner, and it fixed the low idle i had at the time. I just think its idleing too high, i might just go buy a new one, thanks for the help!

Kia Ora
-Dan

 

[l1k2gadd]

If you seperated the two parts (the motor and the plunger assemblies) and you didn't check to see if the plunger moved up and down smoothly you might have bound the two together and the male portion ot the plunger might be sticking or hanging up inside of the female socket of the motor causing a high idle. Again, I don't really know what the factory idle setting should be. Even the sticker on the radiator support of my 1993 XLT says the idle is factory set.