voxleo

Hey y'all, I could use some help as I am having a frustrating issue with my 95 civic ex coupe: recently had thought that my surging idle woes were gone after I replaced my radiator thermostat and o2 sensor n did a whole flush/fill/bleed of the coolant. My CEL was giving me a primary o2 heater circuit code that went away immediately after that whole thing was done, and the idle surge went away for a while. It seemed to do it only when the car was cold at first, but had gotten worse before the maintenance above. This was just a couple months ago and I don't drive much - only a couple days a week sometimes.

Now the idle surge is back. It jogs between about 1000 and 1500 RPMs usually coming shortly after I start the car, but not immediately, maybe after I drive a half a block or so, and doesn't go away when it gets warmed up. It doesn't APPEAR to be a bubble in the coolant system since I've tried bleeding it several times now. Although I did notice that the coolant was low in the reservoir once after the radiator replacement, the level doesn't appear to have dropped again since then.

At one point after I had done the radiator/thermostat/o2 sensor change I got a single CEL that was either 22 or 21 (can't remember which - only that it was vtec related) but that went away on the next start and hasn't returned at all, so I thought it might be due to the weather we had, which was rather extreme cold or hot (can't remember which). But I am not getting any CEL now despite the surging idle problem.

Other than that, it appears to be running well - passed CA smog with flying colors. No power issues or anything, just the idle going wonky in Neutral at stops and such. (It's a manual 5 spd transmission)

Any ideas what could be the issue? What should I do next to troubleshoot?


I should mention I know f***all about cars. I'm a little 5'3 chick who is good at following instructions and handy enough to pull off some decent mechanical work as long as the instructions are good. So pictures and diagrams indicating what part is what when advising is especially appreciated, or at least what section to look it up in the service manuals (of which I have several).


It's bumming me out to have my victory over the last problem so short lived. But I guess it could be worse considering the car is 17 years old. I've had it since there were only 35 miles on her and literally drove it until the wheels (or rather ONE wheel) fell off of it, and I even have a youtube video of that part! ( ) Can't afford a new one just yet, so she is gonna have to go a little bit further , so thanks for any info or clues you can give me towards solving this.

dirty19

iTrader: (1)

Could be a few things.
IACV= idle air control valve
FIAV or FIACV= fast idle air control valve
Vacuum leak.
Throttle body is bad or the TB gasket.

Google these terms using honda-tech in the search string.
This is a common occurance with older hondas, and there has been much written about it.
Sometimes it can be a challenge to find out which one is causing your problem.
If you search youtube there should be some good videos to help you troubleshoot each item.

Good luck keep us posted on what you find.

voxleo

Thanks! Just to know where to start then, are those usual suspects in order of likleyhood/commonality of occurrence?

dirty19

iTrader: (1)

Start with the least invasive... Vacuum leak. You tube has a few vids on this, particularly "Eric the car guy" you will need a can of carb cleaner for this.
The throttle body should be checked for a bad gasket using the vacuum leak test too.
The other two will require removing and cleaning the parts.
Replace if found bad.
If you google this you will have an easy time locating written instructions, and vids on youtube.


Keep me posted.