My car is a 97 dx hatch from the USA. Its got an original 33,000 miles on the entire car..

Everything is mint, except the exhaust I replaced.

Car has never seen snow... Its got the OEM battery in it from 1997...



So as of recent, the motor is idling differently.... I swapped in a cluster about 3 weeks ago, its got a tach and KPH..

I'm pretty sure it wasn't doing this a few days ago, I would have noticed for sure....

when I'm driving, if I press in the clutch, the car won't idle down all the way to 650-700 or whatever the spec is...

It just hovers between 1000-1200 RPM... But as soon as the car stops, it does eventually idle down... But it takes longer than it should...

I just think its kind of weird how it always comes down, but the car has to be stopped... And why the delay in drop when it does come down?

I've also given the IACV a shot of seafoam with no change, besides, the motor is retarded clean to begin with....





Please, any insight would be helpful...

 

CEL codes?

Remove the IACV and clean it thoroughly with brake cleaner.

Also clean the throttle body to ensure that the throttle plate easily closes completely.

Make sure that throttle cable is not adjusted too tightly - there should be slack in the cable.

 

I have EXACTLY the same problem on my y7.

Driving around even at say 5mph in neutral itl be at about 1k, then when i stop goes back to 700.

Things ive noticed were that sometimes i have to blip the throttle to get it to come down.
I clean my iacv and tb every few months and i dont think the throttle cable is too tight it has a lil slack but could be wrong.

If you figure out the problem please be sure to post it, ill do the same.

 

The tb is ridiculous clean. It's not dirty, the car has only 33k on it.

I already removed the magnet to check the action of the iac spindle and it works great.

It only stays revved up while the car is moving. As soon as I stop, the cars idles at 100-1200 for 2-3 seconds, then it kicks down. But the car has to be stopped....

What do the coolant lines do that go to the iac besides keep it from freezing?


Is this how the car regulates cold start idle?

 

Im glad you brought this up, ive been meaning to make a thread asking if this is a normal honda feature or malfunction.

 

it is normal for the idle to go down after stopping. moving idle is set higher than stationary.

 

awesome, ur a big help today thx man, ive been wondering that for a while now.

 

It was working fine the other day though.....

I'd be cruising, and the idle dropped down to normal.

Stops at 800 for 1-2 seconds, then GPS down to 650ish...

Then it started doing the hold at 1000 again...

I guess I'm stuck till the issue becomes more apparent

Any idea about the coolant lines?

 

And Dave

It sounds like we have the same problem.

Every so often, I to need to blip the gas to get it to come down.


I hope someone ccan help


I know something is not right.

 

I have exact same issues as you its crazy. I bothers the hell out of me cuz i cant adjust my idle since its always changing. And i think the iacv measures vaccum and adjusts idle based on that. Spray brake cleaner and try to find vaccum leaks and bleed coolant. I forgot if you already did that. Also like ron said could be your throttle cable too tight.

Edit: just looked it up, ur right all it does it keep it from freezing

 

Done all of that.

Bled the coolant...

Cleaned it all....

Faaaaakk....


I don't want to disturb the TB if its not the problem.

IMO, it's the ecu commanding it to do this.

Or it's something to do with the coolant lines going into that IAC

I really want to know if there is some sort of air flow thermostat built into the iac or not..

Or if the lines are freeze prevention only...

 

You have stock motor and ecu? if so shouldnt be either.

You could try and iacv block off, they sell them or u can make one.

The coolant lines really just loop all over the place so you can consolidate them.

Im not an expert ppl have mixed opinions, some say you need a tune to block off the iacv others say it runs just fine.

But yes I am pretty sure after doing about 2 minutes of reading that they are there soley for freeze prevention.

I would start doing your homework theres so much info about the iacv, seems like everyone has a similar prob

 

My next step is goin to the blood sucking dealer

 

dont do itt

 

if anything take it to a honda shop and ask what they would do and then just do it urself. Or buy a block off plate.

Is it really that bad? Ive been dealing w it for over a year, i guess mines not as bad as urs

 

nvm ur in ma a block off plate prolly wouldnt be a good idea

 

I don't mean that the ECU is screwed up, I mean its a faulty sensor somewhere which is in correctly informing the ECU. which in turn, is making the ECU command the IAC improperly.

My problem is like clockwork. It does the same thing all the time. I don't believe it's a leak of any sort.

I'm going to ask Honda on Monday.

 

ok i gotcha
ya ive been reading up and i think it definitely is the iacv
even if you clean them they can still go bad
http://ecomodder.com/forum/showthrea...ained-967.html
theres an article i was reading just fyi. its pretty boring but informative

 

Its not that bad.... But it ain't right..

I'd like it fixed.

Its tripping my OCD.

 

Okay..


So today I went to Honda.... Complete waste of time..

The car is outdated, and the person at the desk I was talking to was looking at me like I was speaking Chinese..

And the techs were all to busy for me to ask a couple simple questions...

So I went to the scrap yard and got a new/used IACV..

Instead of tearing the entire TB off, I decided to just try the magnet servo...

And so far its working a lot better... Seems to be working normal actually..


One thing I did notice however..

The shaft on the IACV I got from the scrap yard seems to have some sort of spring when turned one one way... It rather stiff... So I checked 3 other car and they all had that spring tension..

Mine does not have any spring tension on it what so ever.... It just floats there.

One thing I didn't notice, was if these cars I was fiddling with at the scrap yard had a manual or auto.. If it even makes a difference...


DAVE!

Does your IACV have any spring tension to one side?

 

First im a noob so dont take anything i say as facts.

But yes mine has a spring, i did take it apart multiple times to clean it and the spring is there to adjust the idle depending on load conditions(i think)

And yes auto and manual are different, a quick google search would give u the answer.

But one is a 2 wire and the other is a 3 so its a big difference.

Edit: What is a magnet servo?

And why would you have to remove the tb to replace the iacv?

Sounds like ur IACV is toast and mine is probably in the beginning stages of what your faulty IACV was at. Cleaning it only works so many times.

 

Well I can say this..

The idle is completely back to normal, but it is better..

The magnet servo id the unit that the harness plugs into.

The green thing.

Its what controls the IAC plunger/shaft.


I tried changing it first, and it seemed to help..

I'm really wondering why the IAC on my car has no spring feel to it..


I'm going out to check something..

 

oh...never heard that term but i know what ur talkin bout

sounds like u fixed half the problem, now throw the new iacv and u should be good

about the spring no idea, but i mean 10+ year part is gonna wear, its only natural for a spring to lose its springiness lol

 

Well I tried the new IACV after you brought to my attention about it coming off without a TB removal...

She was a no go.. Revved all over the place..

Glad I didn't pay for it...

So I cleaned mine up especially the gasket mating surfaces... Also put that newer servo on and put it back together.. and it runs good... Just needs some driving to see if there is a change... So we will see what happens..


Appreciate the brainstorming Dave..

:-)

Is your car an auto?

 

Thats odd about the replacement iacv, was it used oem? or aftermarket

Well I'm glad its working out for you, ive found that honda idle problems come and go very randomly and i just stop worrying a while ago lol.

And not a problem at all, Im glad i could help and you also got me thinking about my own problems as well, even though i just traded today my ej6+cash for a poorman type r

And no its a standard