PhilMac

I have a 93 Honda Civic HB SI 1.6L (engine-D16Z6) 240,000 miles
I've been having a idle problem that I need help with, Please.
Example: when started in the morning idles at 1300rpms (normal) after it warms up it will drop to 900rpms (normal) after driving for about 5 to 10 min. it jump down to 500rpms only when it is at a stop, When driving its fine. While sitting at light every 45 sec. it will idle up to 900rpms and stay there for 3sec then drop. It will also jump from 500rpms to 900rpms when I (open or close the sun roof) ( high beams) (turn the a/c on)- when a/c is on it lacks power on the start up driving but after 2 sec of giving gas you can feel it pick up power, but when costing you can feel the car bog, also when pushing in the clutch it drops close to 200rpms while driving I don’t know if this might be something else or the reason for the idle problem.
Things I have done to it:
1. I have replaced the IACV.
2. I have replaced with new antifreeze and bleed the system.
3. I tried turning the idle screw but it is all the way to the right cant turn any more.
4. I looked for leaks around the throttle body with starting fluid nothing.

Is there anything that anybody can recommend besides getting a new car. Lol

Thank you for looking and for your help!!!!!

Phil

crazyguy

how old are the spark plugs and wires ..and inspect all the hoses for a vacume leak.

PhilMac

Spark plugs were spaced and replaced 2 months ago. wires are 2 years old, i looked for sparks at night but nothing.

crazyguy

check the hoses for a vacume leak and also your ac compressor is working fine? not seizing up right ?

PhilMac

I will check for leaks,Would the ac compressor cause the idle problem even if it is off.
Thanks for your Help

instructor74

Wow 99% of what you are complaining about is 100% normal. The engine should idle around 500 rpms when warmed up ( the little dash just above 0 on the tach). When idling anything you do that creates a load on the electrical system or engine will cause the rpm to increase ie turning on the head lights opening the sun roof = an electrical load and the rpms will rise. pumping the brakes or turning on the ac = a mechanical load and rpms are going to rise. As far as a lose of power with the ac on your engine only had around 126hp when new the ac compressor sucks up a lot of power when it is running so yes the car feels sluggish until the rpms come up.

About the only thing you might want to check is the fitv (fast idle thermal valve) once the car warms up remove the air intake at the t/b you will see to holes cover the bottom one with your finger if you feel suction then the fitv is leaking and needs serviced or replaced. * I don't think this is your problem if it is leaking it will cause the idle to bounce/ hunt up and down all the time once the car is warm. Everything you have posted sounds 100% normal. Just give it a good tune up and be happy that your car runs so well with 240,000 on the engine. I have 225,000 on mine and have owned it since new this is the way they run