JarvisW

94 Sol, with Z6 and only mod is short ram.

I have a rough and variable idle.

Cold is fine, runs about 1500 down to 1100rpm but once it warms up it drops between normal at around 8-900 to REAL LOW around 350-400 and back! Have no clue when its going to do it. its also very rough, and shakes everything.

YES, I BLED THE SYSTEM! on ramps, fan ran 2+ times with bubbles coming out and topping off as necessary. (even repeated it twice)

As per the FSM I took the Ram off and plugged the lower hole in the TB with my finger when fan came on (operating temp) and it was still sucking tons of air! (gonna try to plug it with shop towels and tape)

Now, the FSM says to replace the FITV if I still get suction when warm, the problem is, I tested the FITV when I cleaned it with HOT water and when it was hot, I could not blow thru the round hole, but when temp was normal I could. Took me a while to set it that way too.

I also sanded the face where it meets the TB of it a bit and measured both the groves and the seals with a micrometer and the seals are at least 0.015 larger, so I dont think its leaking from that. (?)

Anyway, has anyone ever run into this before? I'd rather not spend $1-200 for a FITV if its not the problem.

Thanks!

Former User

Doesn't sound like an FITV problem. Did you clean the IACV?

Ohmega

iTrader: (1)

When the car is choking, or Rpm is dropping to near 0, then there isn't enough air going to the engine. If the idle is high, and starts fluctuating, there is too much air. Makes sense if you think about it.

Clean IACV and report back.

White_EG1

FITV only functions during cold start, once warm the IACV takes over... So I would start there.

Clean the IACV out with brake or carb cleaner.
Also inspect the gasket.
Reinstall but leave the plug for the IACV off. Disconnect neg batt, and start the car.
Adjust the Idle screw on the tb until idle is stable while car is warm.

Might as well clean the FITV while your in there though, its right under the TB. Clean with carb or brake cleaner, then screw the plunger all the way down.

Once I did both of these I never had idle problems.

NotARaCist

iTrader: (1)

Don't do that. Just...don't ******* do that. Don't be like that guy. That guy is gone. We don't need another one of him.

JarvisW

Lol that was just to see if yall were payin attention

I did clean the IACV a while back, and it didnt change. I've checked for leaks and can't find one too.

I'm kinda stuck on the lower hole draws air tho. It does create an almost full vacuum on my finger, so I'm thinking the FITV seals are working?

I'll do the IAVC and adjust idle, but if its hunting, Im not sure how accurate that will be?

Also, being Texas and all, can I just tighten the FITV till its totally closed and go from there? If it still draws from the lower hole, should I replace it then?

Thanks all!

Former User

The FITV is not the problem. If it were, you'd have a high idle problem not a low idle problem.

JarvisW

Ok, but wouldn't it pulling air in the lower hole throw off the idle? Tho, I can see that it must work some as it does change idle.. hmm..

I'll do the IACV tonight and go from there.

Thanks!

MisereNoire

possible defective coolant temperature sensor, ECT, under the dist. idle/air bypass is modulated via coolant temp during idle, if it isnt being fed the right number, it wont idle well.

basic info HERE , check post 6

JarvisW

Ohh, good idea.. Same with Slowmo.. I'll check that too.

Thx. I'll do them all sometime today. (busy working on moms van)

JarvisW

Well, I pulled the IACV cleaned it again, let it drain out (I didnt disconnect the coolant hoses because the van is occupying my ramps atm..) but it was still clean from the last time, and everything looked intact. (Didn't do the coolant sensor either but its always been a steady needle, so prob not it) (Also, looked at grounds. but didn't find one that was corroded or fried looking)

I put it back, disconnected harness, and started it while still warm, and it dropped down to about 650 or so.. Thought that was odd, so I started adjusting it down to as close to 420 as I could get.. And the Idle screw bottomed out. I don't have a digital tach, but my old sunpro says its around 450ish..

I plugged it back in then started it and it acted like it was still off! then I hear a LOUD Buzzing so I unplugged it and that stopped! (did NOT make that noise b4 cleaned it) So I figure the IACV is going out.. I try it with one from my dads Z6, and while it didn't allow me to adjust lower than 450rpm or so, once I plugged it in and reset the ECU, it seemed to run a LOT better, and with much less rough idle.. Its is still kinda rough, but Its much better, and maybe now due to #3 cylinder being about 195lbs instead of about 210 like the others (still in 15%, but enough i guess)

I also checked the timing, and its off just a tad. Its lined up at the furthest left line of the 3 on the crank. And I can't move it any further to the middle line!

So, I have that to iron out later..

QUESTION, I guess what I'm thinking is that its still pulling air from the FITV so the idle screw does little to the idle until its all the way in? Or is it normal to be totally bottomed out?

Thanks guys! I hate that I may have to buy a $200 part, but at least I know replacing it helped.

JDMswagSerf

Maybe This will help.
https://honda-tech.com/honda-crx-ef-...-2-3-a-699787/

http://www.team-integra.net/forum/19...your-fitv.html

MisereNoire

Jarvis, the ECT sensor i was referring to doenst send to the gauge, it's wired directly to the ECU to give temp input in order to modulate air bypass via IACV which will directly affect your idle. its a 2pin plug type connector. I believe the temp sending unit for the gauge is a single wire/pole unit that is located next to the ECT. 2 very different sensors. While they both report the coolant/engine temp, they report to two isolated systems.

JarvisW

JDM, I cleaned it and reset it, as I said in the OP. I can blow thru it at temp, but above about 190f it closes.. at least from my testing.. I'd like to see a couple more opinions, then I may just close it all the way since spring is coming soon anyway. Thx tho.

MN, I was going to change it out with my spare one, but cant yet because I wont be able to bleed it. When I do I'll put the hoses on the IACV too lol. (old one is in the loop, but tied off to the side) and swapping the IACV helps anyway too, so, its prob not my problem.

I can live with the way it idles now, but will watch it for the next couple weeks to see if it reverts back to really rough and hunting.. its now stable and slightly rough..

My question for now is does the idle screw bottom out and it not going below 450rpm normal or not?

JDMswagSerf

I have had 2 cars where cold bouncing idle was fixed by screwing in the fitv in almost all the way.
A 95or96 integra and a 93 civic.

So your idle no longer fluctuates and now you deal with a low idle?

JarvisW

lol read my posts.. especially yesterdays update.

I HAD a hunting idle (OP)

Replaced IACV and now have a STEADY idle (post 12)

It was never off cold, ONLY Warm, and now its adjusted close to FSM spec, but not sure if its normal to bottom out the idle screw (It has a new o-ring), and still curious about the FITV sucking air when warm(FSM says its not supposed to), putting 2+2=5 possibly, but maybe they are related.

JarvisW

OK, I am sorry JDM.. I didnt realise I didn't include that along with the new IACV and after plugging it in, the new less rough and non hunting idle is back to around a true 650-700 and about 750 when lights are on..

Oops, seriously thought it was included.

Thx guys.. STILL have a question tho lol

JDMswagSerf

If it says its not suppose to suck air when warm, then why are you curious about it? Adjust it to where it wont suck air when warm.

Ohmega

iTrader: (1)

450 rpm with the idle screw bottomed out is normal. Had you not been able to reach 450, that would indicate a vacuum leak.

JarvisW

JDM, I did, or at least it was open when normal temp, and closed when about 180f. Since operating temp is higher, I figured it would be closed for sure! Guess not. Think I'll screw it in a few more and see what happens.

I'm fine with the way its idling now, still a tad rough, but like I said its got a cylinder down just a tad, and I'm trying to put off doing the head till I can do clutch and belt/pump all at the same time.

Ohmega, that's interesting. I was theorizing that the FITV leaking air was letting in enough air for it to run, and if it was closed the Idle screw would be out a lot further.

Guess I'll find out tomorrow when I play with the FITV (going to count how many turns it is from bottom too)

MisereNoire

Weird, I can stall out my engine before bottoming out the screw...last time i played around with it, i saw the engine register 340 rpm on my external tach before stall, and the idle screw would still turn nearly a half revolution before fully closed down.

My personal experience with this has been that I can achieve between 340 rpm - 600ish rpm by the idle screw alone (with IACV unplugged of course, so no ECU/IACV/ECT interference) resulting in an ECU controlled idle that acted as so:

LOWEST: 510-520rpm ECU controlled, would be very rough and would hunt upward occasionally.

HIGHEST: 1500-1600 rpm ECU controlled, typical symptoms of erratic high idle that you see MANY threads about...hunting, bouncing, and basically just unhappy idle.

OPTIMUM: 600-700 rpm ECU Controlled, smooth stable idle, only changes of idle occuring at change in engine/electrical load.

There was a time when my idle (which was properly set) would be normal during warmup (After initial open loop cold start, and before 180+ degree running temp), but after at least an hour of driving would decide to drop idle into the 510-560 rpm range and just stay there until the engine cooled significantly. I found the problem to be my ECT sensor.

It is very likely possible that a lot of idle problems stem from the seal around the idle screw being degraded to the point of allowing bypass/loss of adjustment, after all, in the 5th gen civics, any original seal is now at least over 20 years old.

JarvisW

I'm gonna play with the FITV tomorrow, if I can get it to close, I bet it won't start with the Screw bottomed out. If I can't get it right, I'll just go back to where it is now, since I can live with it.

MisereNoire

Saw that, it's why I generalized the statement. I figured at least someone out there might see it and go "oh...yeah". Good luck on it man.

JarvisW

Yeah, thats kinda why I'm still posting my results, even tho I can live with it for now.

Update: I closed the FITV all the way, and it would not start with the IACV unplugged, but would a 1/4 turn out. BUT, its still drawing enough air to give my finger a hickey if I left it there lol! (It does NOT kill the car when IACV is off and idle is low to plug the hole.. interesting!)

I also found #3 spark plug was loose and "Tuft tufting" so I tightened it.

Its idle is now as close to 420 as possible (CELEBRATE!!, light one up lol) with the IACV unplugged.

I need to fill up and run some gas off, but it seems to be smoother and possibly less rich too.

I still can't turn the Dizzy tho. Timing mark is at the far left line, and I cant bring it any more around to the middle line. The adjusters are all the way over and its on correctly too, so I don't know how that happened. I can't stand trying to figure out other peoples work lol.

Thanks

MisereNoire

Well, sounds great as far as your idle goes, but you not being able to time it right sounds like your mechanical timing is off by a tooth or so.