Idle issues

Well, I have a random IACV problem. Every now and again I get the fluctuating idle when the car is warm so I have to unplug the IACV, reset the ecu, so on and so on.

But I'm having another completely seperate problem and for the life of me I can't figure it out. First, my car idled fine before the engine swap. I can't find any vacuum leaks, TB gasket and IM gasket were replaced. Only problem is the finnicky IACV. My question: Would the IACV make the engine drop down low then back up to the set(stock idle) RPM after letting off the gas? If I'm driving down the road and I come to a stop, I clutch and let off the gas, when I let off the gas the idle drops down below 500 then normalizes at the set idle(roughly 800-900). Sometimes it can bob below 500 up to 1000 back down to below 500 then finally even out. This will also happen if I rev the car. Its almost like its going to die on its way back down the RPM's

I'm sure it has to do with the IACV, haven't tested it with my Ohm meter so maybe I should do that. Didn't know if there were some other things I was missing to check out.

Comments

  • skinnyskinny Senior Wagonist
    Its your FITV. Its under your TB. You unscrew one end of it and screw the plunger back down. after so many years they work their way out and create a internal vacum leak. We just got the alternator done. we were looking at the new shiny part and realized the clutch cable housing is fucked. so were off to acura for a new one. IF you need more info call me or something and I can explain more :lol:
  • Sorry no FITV on (most)ZC's and no FITV on (most)obd0 TB's, only backs of IM's. I say "most" because Honda always had that one off exception. And that one off exception always makes me look like an incompetent fool :lol:
  • wagodizzlewagodizzle Council Member and EDM expert
    my intake mani had one when i did my MPFI swap. i just never wired it up :lol: works fine.
    on a side note, i ended up with a unique manifold- it had an extra nipple for coolant flow, didnt plug anywhere and other ones i saw online didnt have it. so i just had to block it off :roll:
  • skinnyskinny Senior Wagonist
    Umm my integra has one and so does my current ZC. Are you sure were talking about the same thing? OBD 2 cars dont have them I know that for sure.

    http://www.honda-tech.com/showthread.php?t=2153910
  • First off, this thread is not about arguing about which cars have a FITV. The IACV(EACV) is the valve connected to the back of the IM with the 2 coolant lines running into it, it is right next to the TB. The FITV is connected to the throttle body(if its temperature controlled) or mounted on the IM closer to the brake booster vacuum line(if its the electric solenoid). The FITV is not controlled by the computer but in some cases(like my old D16A6) it is an electric solenoid not temperature controlled and can be left unhooked because it is purely a mechanical valve that does not send feed back to the ECU. The IACV uses the temperature of the coolant to open and close and relays the position of the valve to the ECU so the ECU can adjust to it. What I am referring to in my first post is the IACV.
    #12 FITV ********* #13 EACV(IACV)
    2.gif
    Solenoid on the left = FITV ********* 2 holes on the right = IACV(EACV) holes
    121.jpg
    Please notice this is my old PM6 IM not the PM7


    My DOHC ZC doesn't have a FITV on th IM nor did it have one on the TB. And most of the D-series motors I have seen didn't a FITV, not to say that there is no such thing.
    Now that I have made myself clear on the problem I'm having, has anyone had this problem of the idle just falling off after letting off the gas. I suspect its a faulty IACV seeing how I can cover the IACV hole in the TB and the car dies meaning no vacuum leaks at the least. Just thought maybe I was missing something adn it never hurts to ask questions. :D
  • skinnyskinny Senior Wagonist
    could just be the tuning?
  • wagodizzlewagodizzle Council Member and EDM expert
    i have heard of IACV going bad quite often. so source another one and see if that helps.
  • skinnyskinny Senior Wagonist
    yeah IACV go bad all the time over at pgmfi
  • Yeah I need to test mine first. Just to let everyone know 8-15 ohms is factory specs. Probably have to pick up a new one.
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