Well, I decided to clean the TB and IAC tonight. Took it out for a spin, and the idle now fluctuates MORE than it did prior to the cleaning, and the low RPM hesitation is as bad as ever. Especially in first gear, of course.

Why would this issue worsen with TB/IAC cleaning!

Also - there is a slight and momentary hissing noise when releasing the throttle plate, as the intake reverts to IAC intake. Is this normal?

Did you use a new O-ring, when you reinstalled the IACV?

I didn't remove the IAC or TB - I removed the intake tube and sprayed them down while manually manipulating the throttle.

I would remove the IACV from the plenum and clean it with brake cleaner. Ditto for the IACV hoses. Ensure upper and lower ports are clean.

I realize that would allow for a more thorough cleaning, but why would my quick and dirty cleaning make matters worse?

And, is it normal to hear a hissing sound when the throttle plate closes?

BTW - the TB looked pretty clean, the IAC was likely pretty clean as well.

Not sure. I've never experienced what you are describing.

Sounds like some sort of vacuum. How does the IAC/throttle transition occur? Via vacuum? Does the IAC close completely when the engine is using the throttle, then reopen when the throttle plate closes completely?

The throttle plate is not suppose to close completely (but almost). There should be a slight gap--about the thickness of a sheet of carbon paper. Under guidance by the ECM, the IAC motor opens and closes the valve, which regulates idle rpm by controlling air flow through the hoses by-passing the throttle plate. There's an IACV inlet screen that often gets clogged with dirt. Nothing improves idle more than thoroughly cleaning the IACV, hoses, and ports.

OK, OK, you've talked me into this heinous job!

I hate dealing with coolant more than anything. I'll soak in carcinogenic used motor oil all day long, but coolant gives me the willies. Call me weird.

And, I have to find replacement gaskets for both the TB and the IAC. IDK if I can find non-OEM gaskets. Probably, after driving around to 3 or 4 stores!

I also need a five-point bit set to remove the IAC from the TB. Maybe the TB/IAC were designed by GM!

Reason I want to do it now is of course the "holiday" weekend. On a "holiday" weekend, I can accomplish all the usual domestic chores and sometimes fit in an extra one like IAC cleaning.

Thanks for the explanation.

One other thought - when I pulled the IM to replace my starter a couple years ago, I did not replace the rubber O-rings/gaskets.

Should I do so now? I'm thinking not, those rubber O-rings don't deteriorate like other gaskets, especially in a relatively low heat zone like the IM.

This is a super simple job, in which there's no need to deal with coolant. You likely won't even need to replace the O-ring. If needed, just lightly coat the O-ring with silicone grease to improve seal.

Quote:

---

Originally Posted by TxGreaseMonkey

This is a super simple job, in which there's no need to deal with coolant. You likely won't even need to replace the O-ring. If needed, just lightly coat the O-ring with silicone grease to improve seal.

---

Ha!

The IAC is UNDERNEATH the TB, there is no access to remove the IAC without first removing the TB, which of course has coolant lines attached to it.

Why do you think I first chose to just spray TB cleaner without removing the IAC!

IM gaskets should always be replaced and torqued evenly (and in proper sequence) with a torque wrench. They get compressed and don't seal properly. All it takes is a "little" leak. I would replace them.

IACVs are always on the rear of the plenum or on top. I've never seen one on the bottom.

Here's a Honda parts catalog, it shows the IAC (#1) on the forward bottom. And, believe me, there's no way to get tools in and beneath the IAC to remove it from the TB.

http://www.hondapartsunlimited.com/s...temcomp=Engine

Sounds like I will be on a gasket hunt this weekend. Hopefully I can find one store that has all the gaskets I need.

Is this what your's looks like?

http://www.superhonda.com/photopost/...n_sale_001.jpg

Remove both of those bolts and off it comes. The "figure 8" O-ring is inside.

Mine sort of looks like that.

You know, the idle is pretty normal - it's settled down since last night, maybe I dislodged some dirt and/or otherwise disrupted things enough that the ECU had to relearn.

The RPMs don't act up when I put the car in 1st and let go of the clutch, but the car just doesn't want to get up and go, unless I release the clutch and depress the gas JUST SO. Makes me wonder if the IAC has anything to do with this annoyance.

That's not an IACV issue. Have you ever replaced the Ignition Control Module and coil?

No, don't have those - but I have replaced the ignition coils and was thinking about getting the ECU reflash by Hondata.

Guys that have had their ECU reflashed claim it eliminates hesitation - just don't know if my hesitation is normal or not for this car. I'm thinking not; I don't recall it being this bad until recently.

The other thing these cars are notorious for are faulty TPS'. But I'm not sure what the symptoms are.