Dwaynep

I've got my 2000 Honda Accord 2.3 ULEV with a bent valve in the garage to fix it. I got the 2 bent exhaust valves replaced 😀. But now I have extremely fast idle when cold, 2000 rpms, and when it warms or throttle is tapped it starts hunting going from 1000-2000 rpms and won't stop til the car is off. But here's the kicker there are no codes. Figured it was a lack of coolant in the IACV so I drove it for 10 minutes with heat on just to get coolant flowing. Still no luck. I unplugged the IACV and restarted the engine and the idle still hunted but not as high. This is my first Honda so I'm still learning this thing. Also while changing the valve I kinda adjusted the rocker screw thingy just to see if the valve just wasn't closing cause it was too tight........ And now there is a slight tick on that side of the engine 😔. I am at a loss of what could be causing the idle hunting. The ticking I can fix. Any help or advice would be greatly appreciated.

Knownworldwide

Make sure you bleed the cooling system completely. Sounds like there is an air bubble trapped in the system.

Dwaynep

Update: I rechecked the coolant and ran the engine heater is hot all lines to and from he throttle body are full of coolant and hot. The system seems to be pressurized and full of coolant. Coolant is flowing so I don't think there is an air bubble trapped in the system. Anything else I should be looking for?

brakedrum

What RPM range is the Idle at with the IACV unplugged? If the idle settles to a very slow, barely keeping running, level, then your IACV might be the proper. They do go bad. Especially if any cleaning was done to them and the chemicals got into the electronics. Did you get a Check Engine light from the IACV being disconnected? If no code, and you know the dash indicator works, that would suggest problems with the IACV, or the computer.

Anything deleted or blocked off on the car? Intake Manifold gasket replaced if you had the Intake off of the engine while working on it? I don't know if the 6th gen's have them, but if there is a Fast Idle Thermal valve, you should check it. If the EGR valve has been messed with, make sure it is working, and has a proper gasket seated in it.

If all else fails, you may need to plug in the IACV and spray some starting fluid around the intake to see if it gets sucked in anywhere causing a big surge in Idle, almost like stepping on the gas.

angrysmileyface

Check the PCV valve ontop of the engine. make sure its connected properly, hoses are not cracked and if its any good at all. Follow other suggestions of trying small amounts of starting fluid around vaccuum lines or the brake booster.

Dwaynep

Sorry for the delayed response. @BRAKEDRUM with the iacv unplugged I get p1519 and the idle bounces between 900 and 1400 rapidly. That's the only time I get a iacv code. I don't have starting fluid on hand but I do have brake cleaner and carb cleaner and I sprayed both on all vac lines and all around the intake and nothing happened. Just as a test I sprayed both into ports for the iacv and got a code p0505 (I think). No mods done to the car everything is bone stock. The only mod this car is about to get is the license plate delete mod.