95LSv

I got a 93 civic ex, automatic, and when the engine is cold and I start it, it revs up and down between 1000 and 2000 rpm but only until the engine warms a little... I just did the headgasket, and the problem is still there and was there before too, I replace various vacuum lines and cleaned the iacv too... What could it be? Thanks

95LSv

Anyone?

Shameinator

my guess would be an air sensor somewhere. are you throwing any cel codes? You could also have a vaccum leak. That would cause and eratic idle. CHeck your coolant system make sure the air is flushed out and the coolant is topped off. Also check your grounds make sure they are clean and have good contact.

cruzalekz

you most likely got air in your cooling system (coolant). try doing a coolant flush and when filling it back up, keep the heater 'on" and the radiator cap off and wait until the bubbles disappear frm the radiator.

or maybe your ect is starting to go out intermittently.

during warm up, you are in open loop so the heart of the system is the ect at that time thus will be the only sensor responsible for your issues

95LSv

I will try to do a coolant flush... The ect I just changed because it was throwing a code 6 (ect), after I changed ect the code went away, however the erratic idle stayed

Shameinator

wow I should really work on my grammar :doh: I meant cooling system not coolant system.... I wonder how that would work lol.

95LSv

Flushed my cooling system, replaced all coolant and bled the system and still it idles weird when cold... As soon as the engine temp starts going up, the idle goes down to 800 and stays there... What else could it be?

A-series

It's either the EACV (called IACV on newer models), not that the valve itself is necessarily at fault, that's raising the idle or something is letting too much air in until it warms a little.

Try disconnecting the EACV, just remove the clip at the bottom of it. Start the car this way or disconnect it right after starting, so the engine is still cold and doing it's regular fluctuation. Depending on the condition and setting of your FITV and base idle screw, you may need to give it gas to keep it from stalling (until it warms a bit).
If that fixes the problem, you know the source of the raised idle/fluctuation is the EACV, not a leak somewhere, etc. Then you can investigate why the EACV is being retarded when cold, or why the ECU is telling the the EACV to be retarded when cold.

If that doesn't help at all or only improves it, but still fluctuates, try this: Again, w/ the engine cold enough that it would normally fluctuate w/ raised idle, remove the intake tube at the TB. There's an inlet port at the top (for EACV) and the bottom (FITV). With the engine running (might as well leave EACV plugged in for this, so it doesn't stall and won't affect results) try plugging each of those ports one at a time with your finger/thumb. If plugging one fixes the problem, you can go from there.

94civiccupew/b7

clean the fitv. it's on the bottom of your tb. disassemble, clean everything with brake cleaner and put it back together. should help if not fix the problem

95LSv

Thanks a lot guys, it seems to have been the FITV. Took it off, disassembled it and scraped all the buildup off with a blade then cleaned it with brake cleaner. There was a ton of buildup and the sensor side... Now the car idles fine. Thank you.