serjey15

Dude thanks alot!!!!
I followed you instructions and now my idle is perfect!!!

zoidburg

So i put a 93 b18a1 in a 91 teg. then idle does the whole 1 to 1,5 back and forth wab wah wab wah. So i go thru and do everything posted above, pulled the iacv off three times, pulled and took apart the fits, checked for vacuum leaks bled and rebled my coolant. No avail. well it ended up being nothing ive ever read on a blog.(and ive spent hours on blogs). It ended up being a couple of adjustment screws on the throttle cable. If the cable is pulled slightly it causes the engine to try to adjust, i know its a rookie mistake but hey thought i post for other rookies. but ya no more wab wah.

grumpy79

Ive got the same problem on idle surge but my idle bounces from 1000-5500rpms no cel is on but Ive done what was said in recent post still surging.I read last night that if you cover one of the two holes in the throttle body and when i cover the top hole it fixed the problem so does that mean it is the TPS sensor?????If it is why isnt the ecu picking up a bad sensor???? Thanx for any help my fellow HONDA GURUZZZ!!!!

slowman

iTrader: (3)

Bumping this up cause it just saved me!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

'93 STULUDE

I watched your video about the bouncing idle... my '93 h22 lude does the exact same thing. Did you ever repair it? if you did? i would love to know what you did... as you know, its the most frustrating thing i've ever dealt with!!!!
thx

John Sylora

I have a 92 Prelude with a similar problem to RicanLuder.. the idle surging and the resulting lower rough idle after disconnecting the IACV connector. This led me to remove and clean the IACV and verify it is working using a bench power supply. The solenoid moves the white plastic collar as you apply voltage. If you change the voltage fast enough it actually clicks as it hits its travel limit. This however did not fix the problem.

Next, I removed the FITC valve and cleaned that. I tested this too by disassembling the FITC and putting the end with the temperature sensitive wax inside in a small cup. I filled the cup with boiling water and the pin immediately rose by about .12" showing this still works.

Next, I sealed the intake body with my gloved hand and with a cloth and the car would not stop running. I could hear a slight suction noise but it was difficult to tell where it was coming from especially with a loud surging idle etc. I read on a thread the many ways to find a vacuum leak and tried a few of them. I purchased a Mityvac online and the steel vacuum gun kit included several hoses and attachments. I used one of the hoses with an cone like attachment at each end. The larger end I put in one ear and the smaller cone I used to probe the engine bay. As soon as I began probing, I noticed the sound was very clear using this setup. I could not hear anything too unusual until I probed near the 2nd fuel injector on R(passenger) side. I heard a slight whooshing sound. Probing further in the area of the intake manifold and cylinder head junction revealed the problem.. a very strong vacuum leak at the intake manifold gasket. In fact, the gasket was fractured with part of it sticking up coming away from the junction. The sound using this setup was very clear and produced a very loud whooshing noise as the air was sucked in.

I failed the emissions test with this problem and have had this surging idle for many many months. I'll have to work on replacing the gasket and finally fixing this difficult problem.

Looking back, here is my explanation of the symptoms. The cracked intake manifold gasket caused a large vacuum leak allowing unmetered air into the combustion chamber. This caused a lean state surging the idle and probably leading to my car's smog test failure with high NO readings. The high surging idle causes the ECU to shut off the fuel injectors at 1100 rpm lowering the idle which then results in the ECU turning back on the fuel injectors and raising the idle. This cycle then repeats itself.

The idle would be fine if only the air from the IACV was going in, but with the added vacuum leak air at the intake manifold the idle overshoots its target surging to 2000 rpm. Removing the connector to the IACV shuts off the IACV causing the car to idle rough at around 1000-1200 rpm. This is from the unmetered air at the vacuum leak and the normal air going through the idle screw valve and FITC valve. In other words, without the IACV air the surging only goes to 1200 rpm and the fuel injectors cut off at 1100rpm sending the idle back to 1000 rpm where the injectors come on again surging to 1200rpm. This cycle is what is seen when the IACV connector is removed.

With the IACV connector connected, the idle surge goes to 2000 rpm due to the added IACV air on top of the vacuum leak, idle screw, and FITV air intake. As before, at 1100 rpm the injectors cut out but the added IACV air is strong enough to surge the engine to 2000 rpm. With the injectors off, the rpm then subsides to 1000 rpm as the injectors turn on again and the surging then begins to 2000 rpm. Disconnecting the IACV shuts off the IACV air and the surging can only go to 1200 rpm as described above.

This was very difficult to diagnose since the symptoms make you think the IACV is defective when the real problem is the vacuum leak. I'll work on fixing the intake manifold gasket and hopefully solve this difficult problem!!

Wafler

Now, I've tried all that is described above and I have no vacuum leaks - still the engine is surging metween 1000-1500 rpm. When I block the IACV hole in the TB the idle remains normal.

What good is the IACV? I mean, how important is it? When my idle is fine without it my thoughts are as follows: If I make a block off plate for the IACV, placed between the IACV and the intake manifold - that would surely rid me of my surging problems and all is well?

If anyone has a reason why this should not be done, please make yourself heard

Milliron

Well I have just read every post on this subject. I feel I must be missing something. I have followed all of the steps that everyone has posted. I've taken apart and cleaned my FITV and I've taken apart my ICAV and cleaned it also. I did a coolant system bleed. I replaced my o2 sensor, I've listen and check for vac leaks (1k times). My car ( 93 si 2.3) is not "bouncing" at idle, but sorta. When I first start the car (cold) everything is fine, when it reaches opt. temp it is fine. The second I touch my gas pedal, for the first time since starting it, idle will drop down to 400-600 range, and sit. Once I try to drive it and come to a stop. It will stall. After it stalls (most of the time in traffic) it will not start.
I could really use some help. I have looked over the forum a lot, and I hope I'm not posting something that has already been talked about, but if anyone knows of anything please post a link or some items. At this time I am willing to try anyone's ideas. LOL.

Ps what is normal idle?
Thanks for the help guys, And this is a great thread!

h22blklude92

my idle does not jump at all really. however even after replacing the iacv the cel still comes on for it/ i've tried 3 different ones with the same results. now i wouldnt care at all if the cel stayed on but as soon as i try to get it a little gas it jumps and makes it impossible to just cruise at one speed, so i have keep on the gas enough for it not to jump around or just let off, which is really annoying. anyone have any thoughts. i think it may be the harness itself but who knows

sparknblaze

God Bless You!!!

My ride was annoying the **** outta me with the 1800 RPM idle. I was checking all over the place for vacuum leaks and spraying carb cleaner by the can-full but no dice. After reading this, I plugged the bottom hole inside the throttle body and it started idling normally so I figured it must be the FITV. Removed it, screwed back in the plastic piece (which was a PITA and didn't want to go all the way back down) and it's been running smoothly ever since. Invaluable advice!!!

HondaDrag

I have a SOHC ZC swap in my 93 coupe and when I plug the bottom hole on the inside of the TB the idle smooths out. Dose that mean i need a new fast Idle valve?

holmesnmanny

It is supposed to idle higher when you start the car from cold. If it's hot then there is supposed to be only a slight amount of vacuum coming from that port. If there is a lot and the car is warm already then you just need to take off the two screws and use a pair of needle nose plyers to hold the plastic piece and turn the valve body with ur hand until it tightens up all the way. U just want it snug. It's easier to do that than to try to turn the plastic piece while holding the valve. Otherwise it'll start to kinda strip the plastic piece.

HATCHWH0RE

BUMP for making my idle better!

friutoftheLude

sorry for bumping this thread, but it really helped me out today, ive been looking for a solution for my high idle really only when it was real cold, i bought the car last spring, so this winter is when it first arose, but really been doing other work to it and just got around to the cold high idle situation

It turned out to be my FITV, as i read the first post, i knew it because ive cleaned all the rest of those other valves (iacv etc.) except for the FITV, I knew even more it was the problem as i had to screw in the white round thing ALOT before it stopped, then backed it out a half turn

Also a pair of scissors does work great for that.... thanks Mgags7

F20b97AccordLx

Ya this is a bump...............


This Thread is F$#King Amazing!!!! Thank you to everyone who put in this great info my F20b is running so sweet now. Thank You

boarderfatty

iTrader: (1)

Bumping again. My idle isn't really bouncing, but as soon as I turn on the car the Idle jumps up to 6000rpm.

Details: 1999 Civic SI, JDM B16 bottom end, GSR Head. I just put on a new intake manifold and throttle body ( Skunk2 ultra Street Series IM and Blox Billett 70mm Throttle Body) and throttle cable ( OEM B16 cable) I was able to get everything sorted out and the revs were at 1500 rpm. Smoked the Intake manifold and it was pissing smoke out of every part of the throttle body. MAP sensor, TPS Sensor, Throttle Plate Screw, The pin that goes through the throttle plate to where the throttle cable attaches etc. Like I said everywhere, so I decide to put the stock GSR Throttle body back on.

I put the gsr throttle cable back in reinstalled the MAP sensor, and mounted it. I didn't adjust the TPS from when I removed it, I plugged the TPS and MAP sensors in, I capped off the vacuum line that normally recirc's to the intake and thought everything would be fine. I start the car and the revs shoot to 6000rpm. I check TPS voltage, is is a little out but not much, spec is 0.48 CT and 4.5 WOT, I was getting 0.43 CT and 4.57 WOT, and MAP sensor is reading correctly. I smoked it, and there were no vacuum leaks. I adjusted the throttle cable tension so there was no tension at CT and loosened to low idle screw so that the throttle plate was for sure closing all the way. I start it, and it shoots to 6000rpm again. I adjust the idle screw so that the throttle plate is a **** hair open off of completely closed, same thing, the revs shoot to 6000rpm.

I noticed when I turn the car on and it shoots to 6000rpm that the throttle plate doesn't move. When I installed the BLOX TB I originally set the TPS to the WOT voltage and adjusted the idle screws to get the low voltage. This cause my engine to rev the same, but then I adjusted the TPS to the CT voltage instead and the idle settled out except the vacuum leak.


I am really stumped it should be pretty simple for the things that will control Idle. IAC which is plugged in, and hadn't been changed from when I had it idling almost normally with the BLOX TB, TPS which is out but not drastically, Throttle Plate screw which werent adjusted, vacuum leaks which there are none, MAP which is reading normally, Idle screw which changes nothing etc. The only thing that I haven't really checked is fuel which I dont understand why it would do that, and there is the fast idle which is operated off of coolant temperature (I have the coolant inlet and outlets open to atmosphere since they were bypassed for the BLOX TB) but even then, I dont think the Fast Idle would account for more than a few hundred RPM.

Any Idea's

D'zLude

Thanks to everyone who's posted here. I followed this combined with another thread that has more photos, and cleaned the throttle body, IACV, and FITV. The FITV was 'unscrewed' about 1.5 turns, and the mesh screen on the IACV was 50% blocked by build-up. The car now idles perfectly at about 600 RPMs.

SolusEM1

subscribed

B18cPoweredEm1

Mine bounces, but when I change ecus it stops.. Forgot to mention that as well

speed&metal

This is the explanation I found:

"I dunno...my first reaction with a hunting idle that rolls up and down over a wide range on a Honda is always to VISUALLY VERIFY coolant level IN THE RADIATOR, with engine warmed up and running...what you see in the reservoir is meaningless, if it's leaking anyplace. Sometimes they won't siphon properly if so. They roll up and down because the coolant is surging back and forth over the temp sensors and thermostatically controlled fast idle speed valve, sending the PCM into a tizzy trying to keep up."

Don't know if that's truth, but i's the scuttlebutt.

My '93 Accord was surging something awful b/w 800 and 3000RPM. Got the air out of the cooling system - smooth as silk.

Steve Turner

I got the idle surge in my 1998 Accord 2.3 LX after reassembling everything after a blown head gasket and a top-end rebuild. The problem turned out to be coolant leaking from both ends of the "second" water bypass hose that is "downstream" from the thermostat housing and leads from the U-shaped (or is it S-shaped?) metal tube (which is part water tube, part vacuum tube) and that leads into a nipple underneath the throttle body (which I think is the fast idle control valve that I see everyone talking about). Those stupid little spring-loaded hose clamps were simply not strong enough to keep the hose from leaking (after they'd probably been removed and replaced several times). I replace those spring clamps with regular threaded hose clamps instead, and the leak is gone and the problem is solved.

gceniceros209

This thread was so helpful man. Sure enough it was the FITV valve thingy being loose. Tightened that bad boy real quick and my idling issues are no more. Thanks a lot guys

msh

good write up! (Y)

KaliKustom

Ok so i guess its my turn... lemmy start by saying im an old school v8 guy... built more engines than i can count... but this is my first d15 experiance...1992 honda civic 1.5 (firewall mounted map sensor) so lets start from the beginning shall we?

Car came in ran good tons of power but smoked like a train... did a few checks it was rings... so i poped the head off and droped the pan and did a in frame rebuild... went to get it runnin and I was a tooth off on my cam and it backfired horribly throu the intake with a nice lil fireball(i will come back to this)so i figured timing is off... rotated all my plugs on my cap around and it ran... but like super crap. So i knew cam wasnt timed right..... got the cam set right n fired it back up and ran not as bad but still crap... tps was broken so it got replaced durring rebuild and its calibrated at .40-3.96... now at first it barley wanted to run at all and had a 14 code... so i addmittedly i started picken throu and doin these steps... ive cleaned the iac (found sylicone on the screen) put it together and a lil better but same....FITV was next... it was BAD gummed up but got it cleaned(hardly any water came out at all)... and the car idles ALOT better and about 1000rpm but still not right lil rough... give it gas and it starts surgin from 1200-2200 then revs up crazy nice... (still havent run the motor 5min straight yet) so i figured i would pull the batt cable and reset the ecm.... car started and run PERFECT for about 10-15 seconds....light came on(code 14 again) and starts runnin same as befor.... so i figured maby the ecm needs more time and since i havent broke in the bearing or rings yet and it was idling decent i decided to let her run for awile the temp gauge stayed still for a couple minutes then shot straight to the middle but never moved from there.... now wile this is goin i swear i hear a vacume leak(but its not) just a really loud sucking almost whistle sound coming from cold air intake all of a sudden i can hear a "THUNK" noise from inside the intake tube (please dont think im crazy....) and the car WILL NOT idle.... will stay runnin if i float the gas pedal... but thats the only way.... if the car dies and i try to restart without resetting the ecm it tries to start like the timing is to far advanced... any mechanic knows the sound...

I retried the reset ECM process with the same outcome 3 times....loud vacume sound...THUNK.... wont idle... if u need a video ill make one tomarrow...so... in the mean time...

1. Not very much water in the FITV housing could be the prob? Going to try and bleed system again first thing in the morning... AND test the 2 ports inside the TB(I said i was picken throu the list didnt I) haha

2. The Fire ball out the intake ..... think that it was more than 1 tooth off? And i need to go 1 more??? The plug wires are still rotated... it wont start if i have them correct on the cap....Or could the fireball have damaged somthing??? Maby blew out my intake gasket???

3. Sylicone on the IAC screen... figured out it came from the TB since i found sylicone there(i didnt do it) but if the sylicone was still wet when fired... could I perm clogged IAC

... but ANY help or insite would be appreciated...
my common sense tells me the computer is trying to learn its functions but finds a problem and goes into like a fail safe mode??? I dont understand the THUNK noise that makes the engine just NOT idle...........

KaliKustom

UPDATE
determined the THUNK i heard is the iacv closing.....

Cleaned the iacv again.... cleaned tb again... cleand fitv again... replaced TB gasket... tripple checked my TPS...
covering port to FITV doesnt change anything.... but unplugging iacv stalls the engine... IF i keep it runnin with the throttle wile i unplug it will then idle about 600rpm and a lil ruff.... went to pull apart got a 2nd iacv cleaned it good..... same outcome

IS the IACV syposed to sound like a houshold vacume wile the car is running amd warming up Cuz they both were LOUD... untill eather they close themselfs or i unplug them....

any help here guys?

Still code 14