Gentlemen (and possibly ladies,)
I bought this car cheap needing a water pump (with the 2.2 liter that was a joy to replace.) The car seemed to squeal before we did the job but no other problems.
NOW after the car is back together we're having this problem. I'm unsure how related our fiddling with it was.
When you start the car the high idle stage is pretty normal. As soon as it goes into a medium idle stage the RPMs begin fluctuating from 1250-1750.
CEL is on. We shorted the jumper cable and received 4 long blinks and one short. From what I can tell that's Code 41 Heated oxygen sensor heater.
Unsure if I'm reading the blinks right and not certain if the O2 sensor is my issue.
Once the medium idle is past the car has a normal idle (a little under 1000.)

 

Did you bleed out any air from the cooling system? Air pockets traveling through the FITV or IACV will confuse the idle-control system.

Look over in the DIY section for something about tightening the plunger inside the FITV. That's the fast-idle thermo valve, attached to the throttlebody. Apparently it can work loose & cause that. I don't really know the details since I haven't had to do that.

 

Thanks Jim for your response. We bled the coolant system but no air seemed to escape. It was a steady stream of fluid.

The Idle is now fluctuating differently. It only fluctuates between 1000-1250. Odd that it's changing from the original 1250-1750.

Next we'll look at the FITV and IACV.

Many thanks.

 

Also, I think you also have some kind of boost valve on the other end of the intake manifold. That can also affect idle control, but I'm less familiar with how THAT one works. Still, clean with TB cleaner if any of that stuff is dirty.

 

I'd suggest that you open the top of the FITV and turn the 'split screw' down a few turns.
When the top is off the FITV and the engine is warmed up, you SHOULD NOT hear air bypassing.

 

One way to check the FITV and Air Boost valve is to plug the port with your finger to see if the idle stabilizes.

The FITV port is the bottom hole in the throttle body outside of the throttle plate (also clean the throttle body and both sides of the throttle plate to remove any carbon buildup).

Just remove the air intake tube, start the car, and plug the bottom port with your finger. See the the picture under Part I step 1 on this thread. https://www.hondaaccordforum.com/for...ad.php?t=28486

If the idle stabilizes, then clean and tighten the FITV valve as shown in that thread.

The Air Boost valve (#9 below) procedure is a bit different, because there is a tube that bypasses the throttle body and not a port. Unplug hose 22 and stop it with your finger (see pic below).

 

Well Fitv and IACV we took off tuned up and cleaned. Shelly's runnin B E A utifully. No jumpy Idle, the CEL is off and now my heart is a little more whole!
Thanks a bunch for your time and suggestions!

Drew