weird idle problem

[4wslude]

my car idle jumps from 1000 to 1250 then going down to 800 then it just jumps again also does it with the ac off and if im holding the brake down if i pull up the ebrake and lay off the brake it stops or if i retard the dizzy it stops also sometimes it doesnt do it and idles at 800 smooth then it will idle down then back up start doing it again i cleaned the intake and the iacv to see if that was it and it wasnt i dont know what it can be i checked the tps with a volt gauge and its at .4 closed throttle and 4.5 wide open throttle if i let the car sit and run for 30 min it will finally stop and idle smooth it just started it hasnt never done this befor and i had the car for a year im not throwing any codes im on here alot checking i have a spare dizzy in going to try swapping them in a few days unless its anything else

[Tech5]

could be a few things

air pocket in the coolant (which seems to be the case as you said when it warms up it idles normal)
bad IACV
under the throttle body to you have the ICV? which has white top and coolant lines going thru it? If so you can try adjusting that
Also have you adjusted the throttle body? I don't mean at the cables either

Is your radiator low of coolant???

Is your temp gauge working inside of the car ?

[4wslude]

yeah it does it cold or warm it just sometimes it doesnt do it and sometimes it does i full on coolant i have no leaks and just put on a new radiator cap on and i forgot its a 89 civic with a d15b obd1 swapped my mainstream and the temp gauge works fine and it never over heats and the fans comes on like it should and if you let it sit long enough it it will idle normal but if you hit the brakes or turn on or off the ac it starts doing it again and the throttle cable is loose because i thought it was that being to tight

[1civic]

Check for vacuum leaks, spray carb cleaner around the intake and if the idle changes then you found your leak..

Its that or the fast idle valve under the TB, worst case replace it with a known working one..

Hope that helps!!

[4wslude]

yeah i sprayed carb cleaner around the intake where its meets the head and sprayed there the trotttle body meets the intake and nothing it still did it in going to check the fast idle valve under the intake i forgot about that my other car did it and i had to take a flat head and screw it down and it stopped in going to check and if that works on this car

[Tech5]

replace IACV

I have a few if needed

[1civic]

Take the TB off and unbolt it from the bottom, check to make sure the plunger works and is not broken.. Before you do that I can tell you a quick trick, pull the intake pipe from the TB, you have holes in the TB before the butter fly, plug the hole and post which hole fixed your problem..LOL
Lower hole is the fast idle valve, upper is IAC valve I think.. It's been a while since i used that trick but it's a quick tool to figure things out..

[4wslude]

ok i didnt think of that i will try that when it cools off outside i will try it and put up what happens

[4wslude]

I unplugged the iacv and it stopped doing the weird idle I guess it was bad it's just weird it wasn't throwing a code for it

[Tech5]

it don't have to throw a code to be bad

[4wslude]

Yeah It's weird I'm going to see if I have one tomorow in storage if not I'm going to be looking for one cheap I just only use my ac when I'm moving so my car itsnt bogging at idle

[turbob20]

check to see if carbons holding the pcv valve open or any old vaccum lines broke if so at idle that's a vaccum leak or you can crank it and while it doing it pull pcv line from intake or where ever yours is and put your finger over it to see if it idles down and stays there you can check other ports this way as well. fast idle and iacv can as all stated above. if you can replace throttle body with a known good one as that by passes alot of sensors and fast idle then see if that works.

[4wslude]

I replaced the iacv and it idles fine now and when I took off the old one it was stuck open I still got to drive it and see of that fixed it i turned the ac on and off and it idles fine now I will let yall know if I fixed it tomorow

[turbob20]

cool beans! lol

[4wslude]

It didnt fix it i drove it and it drove fine for like 10 miles after stop and go from stop lights and it started it again I don't know y it's doing it now

[Tech5]

bad iacv where did you get it

[4wslude]

From 94 teg ls he has more of them I could swap it out with another one he has I'm going to work on it more a tomorow

[Tech5]

You need one that someone actually have seen work not some that has been laying around , For people to have so many laying around there might be a reason for that . I have one still on my civic you can hear run and working. BUT I would check the coolant level and make sure you have NO air in the system .

[4wslude]

I'm going to do that and change the pcv valve and do a tune up and spray down the intake where it meets the head to look for a vaccum leak

[4wslude]

I went and looked at the pcv and it was almost broke in half so I put another one on I'm going to drive it later and see if that fixed it

[4wslude]

I think I found something the throttle cable is loose but when it's doing the werird idle if I try to close the throttle body buy hand it stops so I'm thinking I need to adjust the tps I'm going to drive it with it unplugged and see if it's doing it

[00Civic]

I had this same issue, and it turned out to be the fast idle valve. Take it apart, and screw the valve all the way to the back, not too tight though.

[4wslude]

I already did that I have been driving it for a few days with the tps unhooked and it's getting better gas millage and no more weird idle I think my tps is out of adjustment

[turbob20]

there's a way to set it but its been a while so i don't really remember which wires to use to check but you can google tps adjustments and i think its supposed to be either 4.0 throttle closed and 4.5 open or vise versa! some one will chime in on it im sure.

[turbob20]

truthfully i usually replace my whole throttle body with another known good one to bypass alot of problem areas and sensors all at once then get another throttle body. had problem with one sucking air around the idle air adjustment screw, and a bunch with fast idle junk on em mess up. but this way if it still does it you'll know if its on your throttle body or your intake such as a v-leak or iacv ect...

[4wslude]

Ok I'm going to try adjusting the tps and see what happens I just think it'sout of adjustment