PhilMac

Idle Problem-

93 Honda civic si 5 speed (stock) 250,000 miles.

I've been having this problem for about 10k miles.

Start up in the morning idles at 1200 rpms (normal) then after it warms up it is steady at 900 rpms (normal). But once I start driving it for about 10 min. when I stop at light the idle drops then jumps from 900 rpms to 400 rpms every 5 sec. Hasn't stalled (yet) The only way to kind of fix the problem is turning on the a/c, it will kick up to 900 rpms and stay there. I also noticed turning on power sunroof, high beams, it will also correct the problem but after turning the power off same problem.
There are no codes showing.
I have checked the electrical connector on IAC 13.5 ohms good reading I also took it off and cleaned it with break cleaner same problem. I'm stumped. If any body has any suggestions (Besides buying a new car lol) please help me, Thank you.

Phil

rleonekc

on the throttle body theres a little screw that you can adjust that with

NHB

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rleonekc &raquo;</TD></TR><TR><TD CLASS="quote">on the throttle body theres a little screw that you can adjust that with</TD></TR></TABLE>

Just make sure you adjust the idle screw per the manual procedure and not randomly.

If that doesn't fix it, go back to the IAC. Inside that cover plate (on the rear I believe) there is a large plastic flathead style screw. Make sure it is not backed out and really loose.

I'd also try bleeding the coolant if you have the means. I had a 93 w/ warm idle issues; it ended up being the valve lash (which was WAY too tight), but that was more of a near-stall condition not a hunting idle like you're describing.

If you want to make certain the IAC is good, there is a write-up somewhere around here showing how to take it apart and clean it. The guy also shows how to safely apply heat to it and confirm whether or not the plunger is traveling all the way. Sometimes the wax gets old and the IAC won't fully close when the coolant gets hot. Don't forget to do a good bleed after you re-install it.

Good luck

PhilMac

Thanks both of you for your help!!! Greatly apreciated.

I worked on my car last night and it is FIXED finlay. I was looking in to the problem to much it was the antifreeze. Who ever did my tune up last i dont think they bleed the air bleed bolt so there was air in it which made it run funny. I flushed the system, including the coolant drain plug on the engine by the oil filter. I did everything that my Haynes book told me to. It runs like a Honda now. Thanks again for your help!!!

Probot

lol i was having the same problem with my 00 EX Coupe and before i could fix that issue my uh...crank decided to blow apart the bottom of my crankcase..but yea, do what the other guys said

jjermzz

can you briefly explain the procedure, Im having the same problem. On my del sol I changed the thermastat and the solved the problem. but not this time.