weird idle

[ludespeed88]

i have a 99 civic dx hatch. i noticed that the idle seems to be in the 1500 first thing in the morning when i start the car or when i let it cool down the start it. when it gets warm it still stays at 1500 rpm then when i turn the car off and turn it back on while its warm it gets to a good idle at 700 or so rpms. i tried cleaning the iacv and still does the same thing. i unplugged my iacv while the car was running and got this weird juggling idle what seemed to be somewhat low rpms. not to where it would stall though but it wasnt stable rpms either. so idk if its the iacv thats messing up or something else. please help. thanks.

 

[taluzer45]

Does it fluctuate when running? or does it just drop when restarted? If it fluctuates when running it could be a vaccum leak, or it could be that your IACV is just plain bad!

 

[ludespeed88]

no as soon as i restart the car when its warm it stays at a stable and good idle at roughly 700 rpm im quessing where its suppose to be and it doesnt jump or anything. but once i let it completely cool down when i shut it off and turn it back on later the idle jumps back up to 1500 rpms and stays there even after it warms up again. its weird cuz i would think it would go down by itself after it warms up but it stays there when i drive and stop at stop lights and stuff. im guessing it maybe the iacv but i dont want to spend almost 100 bucks for one and find out its not that. like i said the idle gets perfectly fine after i turn it off and on again after it warms up. btw it drives perfectly fine with the high idle too no issues there just bugs when i stop and its reving up too high.

 

[1badej8]

try using fuel injector cleaner or change your fuel filter mine was somewhat like this for the longest time till i changed my fuel filter and now idle is perfecto

 

[Szady]

Check for vacuum leaks. Take some brake/carb cleaner, and spray around where the intake manifold meets the head and the throttle body. If you find where it's leaking, you'll know...lol

 

[RonJ]

Any CEL codes?

 

[ludespeed88]

There is no cel codes on right now but i will try changing out the fuel filter then check for vacuum leaks and see if that works. If not I'll hit u guys up again thanks for the help so far.

 

[ludespeed88]

I was wondering if having a clogged fuel filter will affect the idle? As if it was clogged would make my engine have a high idle then replacing it with a new one would lower the idle? I have to turn it off and on again after it warms up just to get the right idle.

 

[1badej8]

I was wondering if having a clogged fuel filter will affect the idle? As if it was clogged would make my engine have a high idle then replacing it with a new one would lower the idle? I have to turn it off and on again after it warms up just to get the right idle.

if after changing the fuel filter works but you have a high idle just shut off the car unplug the IACV sensor and start the car and adjust the idle screw on the TB to 700-750 rpm with a flat screw driver, after you finish adjusting just shut off the car again and plug back your IACV sensor THEN unplug your back up fuse for 10 sec so that the engine light can go away, then start the car again and let it idle till the cooling fan comes on then shut off and start again then go for a normal drive might take a full tank of gas for idle to be normal again.

correct me if im wrong

 

[ludespeed88]

I believe that only works when the idle is too high and can be adjusted but like I said mine is weird cuz it is high at cold starts and stays high even when driving while you just idle at stop lights but you shut it off then it would be normal and stay normal idle. I will try that but I'm pretty sure it really has nothing to do with the idle screw.

 

[6thGeneration]

How long do you drive it after its warm? Are they long drives or are they only 10 minutes long from a cold start? Also is it an Auto or a manual because from what I've seen, automatics idle slightly higher than manuals if in gear opposed to being in park or neutral. Just from what I've seen. Correct me if I'm wrong.

 

[ludespeed88]

I only drive the car for like prob 5 min or so after I turn it on and then it's warm temp. I drive to and from work from a cold start and the idle is still high. The drive is like 20 min drive. The car is an automatic. The idle is higher on a cold start in park and neutral than when it drive but even then the idle in drive is still too high. Once I put the car in park and shut off and turn on all is normal. :/

 

[ludespeed88]

Any other thoughts before I start replacing parts and what it could be?

 

[b16lewis]

Clean the throttle body, I am not sure if the eks have a fast idle valve or not but there is a wax ring that you can turn back to reduce idle, that gets nasty, bust sounds like a dirty throttle body to me

 

[ludespeed88]

I cleaned the throttle body with some brake cleaner really good. Was a bit dirty.I don't believe they have a fast idle valve.it still has high idle after cleaning throttle body.

 

[ludespeed88]

Any other suggestions?

 

[fronx]

Fuel pressure regulator acting up? Mine was making me idle low though. I changed fuel filter and regulator. My car runs way better now and it only cost me like 30 bucks.