Dekorum

Today after parking for 30 mins to eat lunch, I returned and my car started up with a check engine light and very fast idle fluctuations (sounding as if I had a lopey cam). This has NEVER happened before. I turned the car off, and restarted and the problem disappeared. Unfortunately there's no way that I know of to check a previously thrown error code, even with Hondata.

Does this problem sound familiar to anyone? The only thing I have done recently is replaced the PCV valve and clean the IACV (which has shown nothing but improvements this past week that I have driven the car).

Former User

Jump the service connector to see if a code is recovered.

Car?

Have you cleaned the FITV?

Dekorum

I do not have a FITV. I have a B18C (R) in a 92 EH3.

You're saying that I have a better chance at reading the blinking lights than I do at using my Hondata S00 to get SManager to show me something? I will try jumping it when I get a chance, but after 2-3 different start up and shut downs, I doubt it will be able to recover the code.

Former User

Also try bleeding the cooling system and check for a vacuum or intake air leak.

If the problem persists, then remove the air intake and then put your finger over the hole in the TB leading to the IACV. Does the idle speed drop and steady?

Dekorum

Well do you still recommend checking these things, if the problem is no longer present and only happened once?

Bleeding my cooling system has already been done after I removed and cleaned the IACV. Bleeding with my engine is never perfect because there is no bleeder bolt, which is unfortunate. Also, I don't have one of those large funnels that can go into the radiator and let the coolant bubble up in it, for bleeding.

What is the standard method of checking for a vacuum or intake air leak? There are a lot of vacuum hoses, so is there an easy way to check them all at once?

The only thing I notice is that at some speeds/RPMs, the intake makes a loud whistle sound for a second or so. Apparently, most Honda people have this issue, and I believe it is when the throttle body is open just the right amount to let the air hit a resonant frequency.

Dekorum

Well as a separate issue, along the same lines.. I could not find a vacuum leak and the problem did not persist. But I have done some preventative cleaning and now I have a similar problem with no check engine light.
I cleaned my throttle body with carb cleaner and some rags, while it was on the car. The inside was very black with carbon build up. I also cleaned a little behind the throttle plate and I could see the inside of my manifold is very thick with black carbon build up. After finishing, my car would crank and crank but not turn over. I found out it was my spark plugs, they were completely black and wet (I guess with carbon that was sprayed in the manifold and dripped down on to the spark plugs). I cleaned the spark plugs with some carb cleaner and wiped them down. Unfortunately some of them still look a little dirty as they were very hard to clean up (it is annoying because I just bought brand new NGK PFR7G-11S plugs a month ago.. did I ruin/degrade them greatly?)

After cleaning off the plugs, the car started up. Now I have a very rough idle surge from 900 to 2k RPM. What gives?
I have never had an idle surge at all times, only rarely when the car is cold and warming up. Last week as I mentioned before, to prevent future possible idle problems, I took off the IACV and cleaned it thoroughly with simple green and a brush. During the whole week my idle has been nice and smooth until today when I attempted to clean the TB. Do I need to reclean the IACV now? If I have to reclean the TB, I guess I will unbolt it from the manifold and just clean it with water and simple green as well. Or did I damage my MAP sensor by possibly spraying carb cleaner in or around it?

Here is a video of my idle now:

Dekorum

Any advice?

Dekorum

I removed the TB and the IACV from the motor. I recleaned them both with Simple Green and a brush (after removing the MAP so I didn't get it wet, but leaving the TPS because my gasket was cracked so I was weary about removing it completely). Once they dried I cleaned them with carb cleaner and a rag. I replaced the gasket for the IACV and the TB gasket with new OEM parts. I then bled the cooling system again, for about 30 minutes, with the temperature on my climate control on all the way hot (do I have to also put on the fan?) until I saw less bubbles. I feel that I was still seeing some bubbles as I revved the engine (the cooling fan came on and off about 4-5 times), and I am pretty sure that I would never stop seeing these little bubbles. Maybe I am doing something wrong.

Anyway, I don't think my problem is from the cooling system.

My idle is STILL doing the same thing. The only difference is that the RPMs surge more slowly and sometimes stay at 2k for a longer time. When I disconnect the IACV the idle drops to around 1200-1500 RPM steady. Why is it so high? A year or two again, when I set my idle with Hondata for the first time, I unplugged my IACV and set the idle screw on the TB so the idle was around 400-500 RPM.

This problem is very confusing because 2 weeks ago (BEFORE I CLEANED ANYTHING), my idle was PERFECT. What gives?