Since i can not post in the DIY section I wanted to say thanks and add a little to the sticky that DesertHonda posted to solve surging idles problems on 1990 era accord.

I went thru all the posts listed here. https://www.hondaaccordforum.com/SURGING_IDLE_%3F%3F/m_46125/tm.htm Easy to do.

They suggest checking the water passage on both theIAC Valve and the Fast Idle Thermal Valve. (FITV) Both of mine were "open" but i decided to check inside anyway. Good thing I did. I found that my IAC exit water port was nearly blocked andthe FITV hadcrystallized inside its water passage.(It had a build up of mineral deposits) Once I cleaned all this out my surging idle problem went away. So I would recommend that you take the water passages apart and clean them. Youwill need a tri driver and some silicon to make a new seal for the IAC.

Thanks for the sticky Deserthonda. This site saves me so much money.

Matthew

 

Desert owns a Honda/Acura repair shop in Arizona..he has been one of our greatest helpers here in the HAF...

WheelBrokerAng [sm=americanasmiley.gif]

 

Thanks for the info. I managed to add it to that thread over in the DIY section.

 

Thanks for the additional information. I have a couple of questions though.

How do you take apart the water passages to clean them out?

Why do you need a tri driver and what is it? I think it is a screw driver used for a screw with a Mercedes symbol stamped into it, right?

And finally, what seal do you need to remake with the silicone? The one that holds the IAC to the throttle body or is it used to seal something else?

Thanks

 

The water passage starts upstream of the IAC, then goes to the FITV and then on to somewhere else. (Sorry, I did not take any other piece off.) I removed the IAC from the Intake manifold along with the FITV. I also removed the water hoses going to and from each.

The IAC water passage is at the bottom. It is held on sometri driver screws. These are screws with a Mercedes looking head. Once removed the bottom comes off and you are now inside the water passage. I ran a 1/4" drill thru the inlet and outlet ports to clean them out. This cover has a seal groove in it that is pretty...interesting. Looks to me like it was originally sealed with silicon. I scrapped off all the old seal and applied a thin coat of RTV to it and put it back together.

The FITV came apart pretty straight forward.I cleaned out all the crud, again drilled out the water ports to clean them and stuck it in hot water to re-set the valve.

I hope I remembered all that correctly. I probably should have replaced a number of rubber O-rings while I was in there. I know the FITV's top and bottom O-rings were pretty much solid as were the seals for both of these going to the actual intake manifold. Bottom line is running thru the tech bulletin on the sticky and the step by step from the other link on the stick helped me along. After I cleaned both valves my problem went away.

Hope that helps.