ViZ

ever since we swapped a h22 into my prelude it has the idle surging problem, it jumps from i think 800rpm to about 1700 (roughly i cant remember) well the guy that helped me install the motor said its most likely because of my fast idle thermo valve.. this guy knows his chit so i followed what he said and bought a new one, im about to install it but there is something i want to be sure of before i make it so i cant return the part... if my car holds a consistent idle till it is warm then starts to surge could that still be the fast idle thermo valve? btw.. it doesnt throw a CEL

thanks

DirtyLude

It could still be the thermo valve. It's a vacuum leak of somekind. Hopefully he did some tests before automaticly assuming it was the fast idle valve. When the engine is warming up, the ECU runs in cold startup mode for a while. Once it's warm, a vacuum leak can cause the idle bouncing.

You should do the idle speed setting procedure listed in the Helms before you try replacing any parts. Sometimes that can fix it if the leak is minor, or the idle screw is just off. Since you already bought a new valve, you might as well replace it to see if that's the problem. If you're still getting the bouce after you've tried those both, you get to hunt for your leak. Good luck, this can be one of the biggest pain in the asses to fix.

ViZ

well i installed teh thermo valve and it was not the problem, i took it right back out to see if honda would take it but they told me they can't so i have a brand new fast idle thermo valve for sale if anyone wants it...
does anyone know what vacuum hose it may be or a good place to start. remeber im not getting a check engine light so im almost positive it isnt the TPS

and thanks DirtyLude for the input

Cottonwoodz

Try adjusting your throttle screw, turn the Idel down, almost all the way.
See if that helps. Mine does the samething, and that stopped it from surging. I was told it is a bad Electronic Air Control, and if the Idel screw is turned out to much, the EAC cant keep a consistant idel. I have changed throttle bodys, and fast idel vavle so far, No luck. I know its not a vaccum leak because it would do it all the time, but only when I turn my idel screw to far out (about 1 1/2 to 2 full turns out)Try that and see if it helps

ViZ

i have been reading about this problem in b-series motors and they mention iacv and eacv... im not sure exactly what these are or even if the h22 has them i think teh eacv is Electronic Air Control Valve and the IACV might be idle air control valve but then again i could be way off..

Cottonwoodz

This is the H22A1 intake manny, The EAC is #20 it bolts front middle of manny, and has a connector plugged into it





[Modified by Cottonwoodz, 3:30 PM 9/19/2002]

DirtyLude

You know what the idle control screw is, don't you? It's just a controlled vacuum leak. Meaning if it's open too much your getting too little vacuum and surging. If you have a small vacuum leak somewhere else you can control it by turning down the idle adjustment screw.

Does nobody have the Helms manual here?

Unplug the wires that go to the Idle Air Control Valve.
Start the car.
Adjust the idle screw until you get to ~550 rpm idle.
Turn off the car.
Plug the IACV back in.

If you have a hard time getting down to 550rpm with the IACV disconnected or you still get the surging, you have a vacuum leak which is too large to control and you need to find it.

del_parker

I had this problem, but my idle was surging non-stop.
First thing I did was check the Fast Idle Valve...it was broken, literally. I replaced that, but the surging didn't go away. It was surging all the way up to 2700rpm before I replaced the fast idle valve, now it was down to 2300rpm. Then I replaced the EACV with another a friend gave me off of his blown h23. That didn't solve the problem, then I read where someone suggested carb cleaner to clean the EACV... So I soaked it in carb cleaner for about an hour, let it dry, put it back on...idles smoothly at 800rpm now.


[Modified by del_parker, 6:02 PM 9/19/2002]

Cottonwoodz

Yes, I know what a Idle control screw is....

But, I dont have a vaccum leak, When I disconnect the IAC the surging stops.So I think its the IAC in my case. Dont ya think?

CaNaBiS

Cotton,

Mechanic got my car fixed today. I told them to repair the hesitation, apparently it was caused by me having the wrong spark plugs, I just took what Twilight Zone sold me b/c they didnt have NGK at the time. The mechanic put some friggin Platinum plugs in there...grand total for the plugs was $70 alone.

He then fixed the idle surging problem to a small degree. He said he adjusted the fast idle control valve by turning it all the way out and then back in a quarter of a turn. But like you said earlier, where the hell did he adjust it? What doesnt make sense is that the throttle body came off of my old engine and my old engine (H23) never had that problem. I wont be able to do it tommorow, but this weekend I will put my JDM throttle body on, and see what that does for me.

Just so people can see pics of the bottom of the throttle body I have posted pics below.

Cotton, the reason I didnt use this throttle body in the swap is b/c it looked like something fell on it during shipment and the throttle cable control mechanism was bent out of wack...when it got bent it changed it position on the idle screw.

In the first pic is that the fast idle control valve? Is there another term for it?

I think I have it back where it should be, but should there be light where the red arrow is pointing to?

In the last pic, is that the idle screw?








[Modified by CaNaBiS, 9:07 PM 9/19/2002]

CaNaBiS

I think I see now where the mechanic must have adjusted the fast idle! I took that plate off and there is a white slotted dial. See pic.

DirtyLude

The first one you have labeled is the throttle stop screw, not the idle adjustment screw. Unfortunately you can't see it in any of those pictures. It a recessed slotted screw above the opening of the throttle body.

You're right, the butterfly plate should be solid against the inside of the throttle body. You shouldn't be able to see that light. I would suspect that that's most of your problem. I found the same problem with a throttle body that was improperly bored out and did not have a good seal. I find that H22a's are more suseptable to surging problems with small leaks than h23a's.

The IACV is what causes the bouncing problem. The IACV is trying to correct for the vacuum leak, over corrects and losses control. A vacuum leak by itself doesn't cause a bouncing idle, it's how the IACV reacts to it that causes the problem.


[Modified by DirtyLude, 11:00 PM 9/19/2002]

Cottonwoodz

So what your saying is if I unplug the IACV,then pull a vacuum hose off the intake manifold(Creating a vacuum leak) the idle wont surge up and down? But if I plug the IACV in, it will surge.

Great, now I got to look for a friggin vacuum leak!!

Whats the best way to go about finding a leak? Replace all vacuum hose's




[Modified by Cottonwoodz, 10:40 PM 9/19/2002]

CBR

How do you find a leaking vacuum hose? Easiest way is to take a needle nose plier and start pinching off vacuum hoses. Once you get the right hose pinched off, the engine should idle smoothly.

You could possibly have a bad MAP sensor, unfortunately this can only be tested with a lab scope and a vacuum pump. Try disconnecting the vaccum source for to the MAP sensor, the engine should still be able to idle and it should stop surging. If you plug the MAP sensor back in and the engine surges, then if all else is eliminated, you have a bad MAP sensor.

Good luck man....by the way, I still haven't figured out why my '96 Prelude VTEC's idle surges whenever the A/C is on and it's HOT outside.

Cottonwoodz

I pulled the vacuum line going to the map senser , and the engine just dies.


[Modified by Cottonwoodz, 10:59 PM 9/19/2002]

CBR

Hmm..that's interesting.

On my '96 Prelude VTEC (OBD2), if you unplug the map sensor connector, or loosen if from the throttle body, it will die.

On my JDM H22A in the CX, with the vacuum line going to the MAP sensor disconnected, the engine will still run, but crappy as heck.

Wierd.

One other thing you can do to try and find a vacuum leak is to get some FLAMMABLE carb-cleaner and spray it around the intake manifold gaskets. Spray some around the EGR gasket too. When you spray carb-cleaner on a place where there's a vacuum leak, the engine RPMS will go up drastically.

On some of the older Honda's, a bad ECT sensor will cause a surging idle. Try grounding your coolant temp reference signal when the engine is surging.

That's all I can think of for now.
Good luck.

ViZ

this is the fast idle thermo valve, (i have one for sale brand new by the way)

CaNaBiS

My mechanic said this is what is causing by surging idle problem. Mine only happens intermittenly, and sometimes it will sit there and idle at 900 RPM's and other times 1100 RPM's.

This throttle body actually is a spare one, I have never used it. This weekend I am going to take the fast idle thermo valve off of it and put it on my car and see if that fixes my problem.

This must be the idle adjustment screw:

CaNaBiS

Is this the IACV valve in BLUE? What does this stand for? Intake Air Control Valve?

ViZ

i think its Idle Air Control Valve. but i may be wrong i just remember seeing that somewhere..
Do they really need so many things to control the damn idle, my old chevy 350 didnt have chit like this, seams like alot to go wrong maybe thats why so many people have this problem..

ArchAngel Sabastian

I think i have the same idle problem you guys have i havent been able to solve it either.
https://honda-tech.com/zerothread?id=261450

Does anyone have a spare h22/23 TB i could buy?

CaNaBiS

My mechanic swore it was the fast idle thermo valve...replaced it and it still does it.

The IACV on my H23 looks different (its a Denso) than the one on my H22 (its a TEC), but the bolt patterns look the same. Are they interchangeable?

CaNaBiS

BTW, make me an offer on the TB, I have one. Actually, its the one in the pics above. I will prolly want to keep the fast idle valve though.

Cottonwoodz

I know the Si IAVC has a differant setup for the coolent lines, I was going to swap mine but never did. See if the plugs are the same and give it a shot.I tryed looking for a vacuum leak on mine, but couldnt find one so I just ordered some vacuum tubing in bulk from honda. Im just going to replace all the vacuum lines and see if that helps.

CaNaBiS

Wow, this topic is getting beat to death. I have more to add though.

I have the surging idle problem.

I took the IACV off my old H23 and put it on my H22. I know the IACV is good on my old engine bc it never had the problem. After doing so, I still have the problem which means that it is not a bad IACV.

But I do have this phenomena. Please explain if you can.

If I cruise down the road toward a stop light, push in my clutch and coast all the way up to the stop light the engine doesnt experience the surging idle until my car comes to a complete stop. How in the hell does my engine know that my car is or isnt moving if my clutch is pushed in the entire time?!