I have had some idle trouble. The car now idles at 3000rpm. When I got it back together three weeks ago it idle fine. So why now?
After some research there seems to be a number of possible items.

1. IACV clogged. I removed and cleaned mine. Wasn't even dirty.
2. Throttle body cable issue. Checked and adjusted, may have been a bit tight.
3. Throttle body, butterfly and air by-pass, dirty, clogged. I haven't check or cleaned yet.
4. Air bubbles in coolant. I have a procedure that has worked for me in the past to keep air out. Maybe I made a mistake.

Anyone else have any idea. Also how could a throttle body get clogged in three weeks.
No CELs.

 

Any vacuum leak?

 

Not that I could find or tell.
Drove on it for 3 weeks with no issues.

 

When I replaced my skunk2 IM, I know for a fact I had a vacuum leak or a bad seal on the intake manifold gasket because as soon as I started it up, the car just idled and stayed at 3k. After I found the source, reinstalled/torqued everything, the 3k idle went away.

 

Any chance he throttle plate is open? See if you have to twist the rotor to the stop.

Maybe one of the screws came out and now it's leaking through the hole.

 

Tried again today. Still no luck. Will take the Throttle body off next. I really don't want to get into the manifold. I hate getting to the nuts under on the GSR manifold.

 

Before you take the throttle body off, remove the intake pipe and then plug the inlet ports on the ID of the throttle body. If the RPM's come down, then you've found your source, but if nothing changes you can at least put them on the IS NOT list.

Depending on whether you have a FITV, you should have either one or two ports. One is for the IACV and the optional one is for the FITV.

 

Changed out a hose I has spliced together no change. I did what you suggested above. It worked now what? I have an IACV, I had removed it and cleaned it.

 

I'm guessing you're OBD-2 and don't have a FITV, so it sounds like the IACV is stuck open or the ECU is feeding it a really high duty cycle.

What are you using for tuning?

 

S300 for tuning.
Cleaned TB need to check IACV wiring.

 

Log the iacv duty cycle and make sure the idle settings aren't out of norm...the target duty cycle should be in the middle and target idle values in the temp-based and minimum rpm should be no more than 1000 rpm when warm and no more than 1700 when cold.

Also, you should see if the idle adjustment screw is still in the throttle body and reasonably tight to turn.

 

I can do this but I am still at loss as to why now. The car ran fine for three weeks then all of a sudden this mess.

 

this may be stupid but did you mess with the cruise control at all?( saying that you do have it).

 

You can always skip to replacing the iacv.

 

I thought about it more to give you something a little more constructive and see the logic behind it.

Log the IACV duty cycle in real-time with the engine on, then manipulate the duty cycle slider or the RPM target values to see if it changes the idle output.

If the idle doesn't drop when you lower the duty cycle, then the IACV is locked up in whatever position it stopped working. It may also be possible to increase the idle speed but not decrease it if the coils in the control valve are only damaged in one direction.

I'm more inclined to believe that the IACV is locked up, but all of the other tests are to confirm that the IACV is the root cause and there's not an additional compounding or other cause.

Good luck and hopefully I'll get to see the car at IFO.

 

I am going to reinstall the TB, fill the coolant and test, again.
I agree the IACV might be done with. If still NG I'll order a new one on Monday.
I won't be able to make it to this IFO. Maybe the fall race.
The car has to be driven to the shop for the new intake piping on Monday also.

 

It looks like a vacuum leak. Intake manifold gasket, time to remove the Outlaw Engineering and back to Hondata Gasket.
Old data when idle was ok MAP shows -13psi at 3000 rpm.
Now the MAP reads -20psi at 2000 rpm.
I think I should fix it before drive it anymore.