I am trying to debug a rough idle problem with my Aunt's '88 Civic hatch-back. It's fuel-injected with automatic and air. It has 69K miles on the clock... a one owner car but it has been baking in the Arizona sun.

At high RPM the engine runs smoothly. But at idle it is rough. I am in Tucson getting the car ready to be smog tested, but I don't want to do that until I can determine a fix for the rough idle issue.

Your thoughts, ideas, suggestions?

-dave

 

TPS, clean the IAVC and FITV with carb cleaner and check for any possible hose leaks.

 

Thanks EFlovin'. I am not a deeply knowledegable car guy so please bear with my questions:

TPS? throttle position sensor? What do I do with it?

What are the IAVC and FITV?

I did check carefully for any hose problems and don't see anything obvious.

Thanks in advance,
Dave

 

^ Great advice. I would start looking for a vacuum leak and then start checking sensors.

 

Yes TPS. Give this a read, it will help with the TPS and any issues that may occur. https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/official-honda-tps-wiring-calibration-thread-2830131/

The IACV is the idle air control Valve. It is located behind the manifold, and there are two bolts holding it in place. WHen you take it off you will see a screen, clean it with carb cleaner.

The FITV is the fast idle thermo valve. Here is a write up. https://honda-tech.com/forums/acura-integra-6/%2A%2A%2A-how-%2A%2A%2A-clean-your-fitv-aka-fast-idle-thermo-valve-1564019/

 

Thanks for the clarification and detailed description of what to do. Will do. It is much appreciated.

-D

~~~

 

Anytime, hope you find your issue.

 

Thanks. First I pulled the plugs to see if anything looked out of whack. This is typical of what I saw of the four plugs:



I don't know if that is good or bad... Comments welcome.

Then I cleaned the screen on the IACV since that seemed easy to do and promising. That did the trick: the idle is now smooth.

Bottom line: I was able to successfully smog the Civic and get it registered. Victory!

Many thanks!

My next tasks: The air conditioning does not seem to work at all, and more importantly, there is a bad vibration when I hit the brakes hard. I'm guessing the front rotors are warped. I will pull the front wheels today to see what I can see.

Thank you again.