StillBaggn

I have gone through countless google searches and my problem is still unanswered.

vehicle: 1998 honda civic hx (d16y5) manual transmission

my idle has been slightly high for the past couple weeks (1100-1200) without any bouncing or roaming, so i searched up how to adjust idle via the screw on the throttle body and applied the action to my vehicle. the idle now bounces up and down between 1000-2000 before the car even completely warms up, ive tried the re-learn procedure a couple times but it keeps doing it. No vacuum leaks.

ive recently replaced: iacv, pcv,fuel filter, catalytic converter, spark plugs, rotor, dist cap, exhaust manifold gasket.

Thank you.

slogfilet

iTrader: (1)

If you put the idle adjustment back where it was, does the bouncing go away?

Have you checked the timing?

StillBaggn

unfortunately i cant remember exactly how it was set. when i have the car warmed up, i unplug iacv and it doesnt bounce anymore it starts to pulsate like a fast heart beat, and that continues to happen while i unscrew it out (counterclockwise), if i screw it all the way in the pulsating dies down a TINY bit, but still does it.

I have not checked timing yet, is there a way to do so without the light or is that the only way?

Coupelife95

Did you make sure your coolant was bled throughly, the slightest bit of air can make our idle weird on these cars. Also check to make sure your throttle plate is closing all the way, or the cable is not sticking. That was my issue

mithious

How did you test for vacuum leaks?

StillBaggn

@coupelife95, i had the car sit and idle for 10 mins with heater on, saw a FEW bubbles here and there but it seemed like it was just because the engine was on and the coolant was flowing.

i will check the throttle plate and look up how to adjust if it is off.


@mithious i just followed all hoses coming off TB making sure they are snug and no holes. , also sprayed tb cleaner on tb and around IM gasket, didnt get any idle jumps or anything weird.

StillBaggn

I went to honda, got a new iacv gasket, put it on, no difference. also drained the coolant completely, added new coolant, started car with coolant cap off for about 5 mins, no difference, I decided to adjust the base idle screw in all the way then out a little and the idle still surges but quieter and SLIGHTLY less, meaning instead of jumpin between 1000-2000, its 1500-2000

StillBaggn

also to add, i took my air cleaner off the throttle body, put hand over iacv hole in tb, engine dies when i completely cover hole, also the main tb hole i covered and it creates a strong suction on my hand and dies.

StillBaggn

bump, anyone?

Coupelife95

When you bleed the coolant let it run with the cap off until the thermostat opens (lower hose gets hot) then it should be good. If you still think it has air crack the bleeder open a few times and make sure straight fluid comes out

mithious

That test doesn't sound very complete to me.

Check under the intake manifold. I had one on the temp sensor on the bottom side of the intake. Unless you've taken apart an IM it's difficult to know all of the places to check, and it's really easy to miss. If you use the tb cleaner method you've got to take your time and be very thorough. Look at the intake manifold diagrams in the service manual.

As you want to do that with the engine reasonably cold (so you don't start a fire), you could check a portion at a time.

Just makes sense to me you've got a tiny bit of air coming in from somewhere. It's not going to be easy to find.

Adjusting the idle screw in the beginning was the wrong move - because it's just masking the issue, even if it did temporarily fix your problem.

Unless someone else can tell me what a steady high idle means, you've got too much air going in.

And yes, check your throttle plate too. Is it clean and seating properly?

Coupelife95

The only other thing I can think of if your coolant is bled, throttle plate is completely closed (make sure to check that, mine had gunk holding it slightly open), and you have no vacuum leaks is the fitv, cover the fitv hole in the throttle body when the engine is at operating temp, if it idles normal, that's your problem

djandy

Correct me if I'm wrong, you said that the engine kept running when you fully screwed the idle screw in, and IACV was disconnected? Where did the engine got air to breath? Mine stalls in these conditions.

StillBaggn

ok, I'll try bleeding the coolant one more time, but on my vehicle i followed the radiator hose to thermo housing and i searched all around the block, i dont think my vehicle has a bleeder valve, nothing that even looks like it

StillBaggn

yea this morning took off tb, cleaned it THOUROUGHLY, used new gasket re installed, same idle

mithious

I think the bleeder valves were only before 96? Someone could correct me here. All I know is my 93 has one and my 97 doesn't. There are procedures for proper bleeding without a bleeder valve, check the FAQ's.

Nice to rule out the throttle body.

One thing at a time eh? My bet is still on vacuum leak.

Good luck!

TomCat39

96-00 doesn't have a bleeder or an FITV. both of these were 95 and below.

To properly burp the car you run it with the cap off until the rad fan kicks on twice. I go for 3 myself and I also like to jack the front end up for added measure, a hill or steep driveway works well too.

I almost wonder if you got a dysfunctional IACV. Seems to be ever since you replaced it and then adjusted your idle, you've had issues.

chrysler kid

Did you clean out the egr?

mithious

Not a bad thought. If it were me I'd clean out the old one and put it back on just to see if it worked.

StillBaggn

ahhh damnit, $100 iacv down the drain if thats the case lol, but the reason i orginally replaced the iacv was because i was getting a P0505 code, and now even though my idle is surging, the code hasnt came back *knock on wood*

StillBaggn

yea that was one of the first things i did chrysler kid, i took off the cap on the im for the egr and all the holes were CAKED! with carbon i mean almost fully caked, so i thoroughly cleaned all it out and whipes gasket off clean replaced.

StillBaggn

as i was working on the car this morning i decided to check all the fuses, i noticed the a/c condensor fuse was blown, replaced it with another 20 amp, started vehicle and the fuse blew again instantly, did it one more time, started car blew fuse again, im not sure if this has anything to do with it, but who knows

tony_2018

Is your radiator fan kickin on at all?

StillBaggn

yes! it is

tony_2018

Did any of the heater hoses, radiator hoses, coolant hoses running to the iacv have any signs of dried up coolant?