JLUDE01

I have a 1996 Accord with the F22B2 (non VTEC) motor, OBD2.

I have researched countless threads on this site on the bouncing idle issue and many people have experienced this, sometimes it's the IACV fault, sometimes it's the FITV, sometimes it's air in the cooling system. I need a way to determine which part may be bad before I start replacing expensive parts on a beater car.

The motor starts up fine but the idle bounces from 1200 - 3000 rpms from cold temp all the way till the fans kick on twice and the bouncing continues. The RPM bounce stays the same frequency and rpm range through the entire temp range!

Now here are two things that may help diagnose the faulty part:

1. There is an electrical connector on the back side of the throttle body, just above the FITV. If I disconnect this with the motor running the bouncing stops and the motor idles at a steady 3,000 rpms! very strange.

2. There is an electrical connector on the IAVC. If I disconnect this with the motor running the idle continues to bounce but at a lower RPM (1000 - 1500).



Someone very familiar with these systems will probably know what is going on just based on these observations.

Yes, I did bleed the cooling system per the Helms manual. I have removed the IACV and sprayed it out with TB cleaner and let it dry. Also cleaned the throttle body and butterfly with TB cleaner and a toothbrush but it doesn't help.

I am going to check if any ECU codes are stored tonight and update this thread.

HELP!

h22 kid

why dont you remove the FITV and clean that one too. not hard to remove... mine was that problem. when i removed that part and cleaned all the crud out of there worked fine..

JLUDE01

Is the FITV on the bottom of the throttle body itself? How is it removed? Looks like 2-3 bolts? I'll clean that one tonight as well then.

h22 kid

yea its held by three bolts.. just becareful when tightening it when you take it off.. you dont want to tighten that yellow cap thing or whatever it is to hard other wise it messes with idle i believe

JLUDE01

Any idea what the electrical connector on the back of the throttle body is for? See the picture in my first post, I labeled it "Throttle body connector".

Disconnecting this connector while it's surging makes the surging stop and it sits steady idling at 3,000 rpms! I can't find anything on what that connector is for since it's not for the FITV or the IACV.

cstone

If you can unplug the IACV and it still bounces then it is not the IACV causing it (I should mention that its possible it could be contributing.) It is most likely being caused by the FITV not holding vacuum. To fix this simply follow directions for tightening the FITV as posted in the millions of posts about this, there is a very good write up in the FAQs. Essentially you take it off (3 bolts on the bottom of it.) Take off the plate on it (2 bolts with phillips head slots on them.) Tighten the white ball shaped kinda thing (it has slots that you can fit a flat head in and is inside the FITV, you will see it when you remove the plate.)

H22 kid: As to the "yellow cap thing" that you mentioned. I believe you may be referring to the part that you are supposed to tighten? Its white though. I've never heard of a yellow cap, nor did I see anything like that when I was tightening mine. I saw a thread a while back when some one was trying to argue that it would mess up your idle if you adjusted the white piece but as was stated in the post hundreds (or more likely thousands) of people have used this fix with good results. The reason for tightening is that the piece expands and contracts in the hot and cold causing it to loosen which creates a vacuum leak which in turn creates the roaming idle, it is not just a quick fix to mask another problem.

Back to the OP. If tightening the FITV doesn't fix it then a vacuum leak somewhere else would be my guess. Which means time to pull out the carb cleaner again and spray vacuum lines, and around all places where there is a gasket on the intake side of the engine (ie. intake manifold)

Oh BTW when you tighten the FITV you will have to bleed the coolant again. You will lose some coolant and let air in.

JLUDE01

cstone: Good info. Yea I have found the thread on cleaning and adjusting the FITV valve.

I believe I answered one of my own questions, the electrical connector on the throttle body is the TPS sensor. Disconnecting this sensor causes my engine to run steady with no surging but at 3,000 rpms!

cstone

Hmm.... the TPS can cause this problem too. Search for how to check your TPS, I believe the only tool you need is a digital multi meter. I think thats in the FAQs too, not possitive. It might be worth doing that before you tighten the FITV. I haven't done it myself but I have heard it is easy.

JLUDE01

But would the TPS have anything to do with idling? If it's sensing throttle position, at idle the throttle should be fully closed? Right?

cstone

But if it is malfunctioning then it may think that the throttle is not closed. It was mentioned to me a while back when I was dealing with a bouncing idle but then it got cold before I had a chance to check into it. I dont fully understand it but I have been told it can cause a bouncing idle.

Since I dont have a shop to work in I have opted to live with the occasional bouncing idle until spring hits and its warmer and dryer. The two fixes listed above did help my bouncing idle a lot just didnt solve it completely.

JLUDE01

UPDATE:

So I took off the FITV and turned in that white plastic piece...it was about 3 revolutions loose when cold! And guess what? No more bouncing idle! The only thing I noticed was that once it warmed up and the fans cycled a few times it was still idling at 1250 rpms according to the gauge. Do I just need to reset the idle speed according to helms?

cstone

yep resetting the idle speed should set it down to where you want it now

JLUDE01

Thanks for the help!

cstone

no problem glad to hear you got your idle fixed.

strebs609

This reply goes to JLUDE and CSTONE (and anyone else that has idle issues).

1st: the ICV does not need to be unbolted from the throtlebody, the inverted venturi and spring need to removed and sprayed out like a mini carburator.
(use 2 small screwdrivers in each slot, or old long nose pliers ground on both sides make matching tapered blades)

2nd: the precise number of 1/2 turns need to be counted when removing the venturi (approx 13 1/2turns).

3rd: the venturi [B]NEVER[B] gets screwed all the way down (1 & 1/2 turns up from the bottom. If you do: the idle runs at 3000 cold & 1500 warm.

IDLE ADJ - set ICV see step3, next gently turn idle adj all the way in and then back out 1/3 turn/faster. Start car & note RPM > then re-adjust ICV venturi up or down 1/4 turn at a time(screw down cover each time). Once your in the ballpark go back to the idle screw adjustment. Older accords/200k+ miles 750rpm

4th: final important step > the coolant gets circulated through the IACV and the cooling system need to be bleeded of any air after the car has been driver for 10 min or idling for 20min. A 10mm socket on a 6in extension cracked open for 10-60sec till it stops sputtering air(never let your overflow resv go empty).

GOOD LUCK

Note: the FITV is a onetime, cold weather startup valve. When it starts getting intermittant, the car will crank and start right up, but then it stumbles and dies. You crank & start it again, and it run perfect(cold rpm settles down normal rpm). It happens once when you start the car and it won't happen again until cars has been off for 8hrs or night.

Personal Log: (pick UR battles - this problem is never worth the time/cost to fix, when U just have to turn the key again) 1st time response, long time Accord owner, i always keep them till the hit 1/4million miles, my '93 at 210k.
Idle was easier to diagnose/fix that the hesitation problem; and putting in a Condenser/converting to r134 is way easier than R&R a Altenator or radiator.

JLUDE01

^^^ Good post! When you say "ICV" are you talking about the IACV? Same thing?

Where is this cover you need to remove to turn adjust the ICV Venturi spring?

cstone

thank you for a great response strebs609! its great to see a newcomer helping out instead of making dumb threads that have been covered countless times. i hope you stick around the forums