Hi I'm new to the his forum and hoping someone can point me in the right direction. I have read this same problem multiple times from forums but can't seem to find the solution. Have bled the cooling system twice, screwed the ring in on the fitv, cleaned the throttle body. Had to replace the throttle body with a used one that had another tps and fitv on it and still had no luck.
When I first got the car it had the typical idle surge and I cleaned the egr passages on the intake and it fixed that problem. 3 out of the four was clogged.
In the winter and cooler weather car idles fine and perfect. But as summer closes in and outside temps rise with the car running warmer it idles high when the engine reaches temp. 2-3k sometimes makes it difficult to drive.
Replaced the iac valve yesterday with a used clean one....no luck. I did notice no water came out of the hoses to the iac valve when I removed them. They were damp at best. Not sure if this is a flag. I have blown through all the passages on the thrott body when it was off. Not sure what else to check. I've heard aftermarket pcv valves can cause problems but not sure if that would be temp related.
Will be very grateful if someone can share info if they know what this might be.
Thank you in advance!

 

A quick way to figure out if the high idle is FITV related is to pull the snorkel off the throttle body. Start the engine and let it warm up to operating temperature. Do the fans turn on? Also, what does the temperature gauge inside the car read. Cover the lower port inside of the throttle body with your finger. Does the idle stabilize?

I'm guessing you meant the hoses to the FITV were not filled with coolant.

Did you use the bleed screw on the thermostat housing to help get air out of the system?

I would disconnect the hoses to the FITV and make sure they are not clogged.

 

Yes I will do that tomorrow and confirm a couple things. I unplugged the iac before I replaced it and the idle dropped so I assumed that was it but may have just been taking the iac from the system so naturally it lowers the idle. I don't know.

And yes the fans turn on and the temp gauge reads about in the middle or normal range as there is not specific reading on the guage.

And the coolant hoses I'm referring to goes to the iac (or at least I thought I read they were coolant hoses. I'll post a pic of the iac valve I just changed that have the coolant hoses. The FITV (fast idle thermo valve locat d underneath the throttle body) is the part I screwed in the plastic ring after removing the cover. Actually one of the two bolts twisted off when doing this had to buy a a used throttle body and it had the tps sensor and the fitv on it already so I just changed the assembly to try and take those components out of the equation as well.

As far as the bleeder screw I did utilize that when I filled the system at one point but I use a funnel that sits high on the intake and actually uses its own cap to seal the radiator. It's designed for removing air in the system and works quite well. You will see any air bubbles being purged from the system and I had the temp control in car set to hot as to catch the heater core as well.

I can bleed the system again and I will plug that hole tomorrow after it reaches temp see what happens. Starting to get a little frustrating but I will prevail. Lol

Thank you for your reply I appreciate it.

 

High on the radiator not the intake is what I meant to say but it's the highest point in the system causes air bubbles to rise etc but I will play with bleeder screw some more see if I can get any more air from the system.

 

The IAC has coolant lines to it. It has been a while since I removed one.

If the testing I suggested doesn't help identify a problem. I'd probably drain the coolant and check that the coolant lines to each valve are not obstructed. That has happened on this (or another) forum. That bleed valve on the thermostat housing is to help push air out of the system when you are filling the radiator and fill the system quicker. You would also have less air in the system to bleed.

The other item that you may want to check (or replace) is the thermostat. I always recommend buying the thermostat from the dealership.

The coolant gauge in the car can vary, but my 95 accord would read about 1/4 to 1/3 on the temperature scale when at operating temperature.