Developed erratic idle when at operating temp with DPFI. (FITV vs IACV)

PrennroPrennro Council Member
in Engine & Drivetrain
This is a repost from my build thread, but didnt get many comments so figured I would post here. Any advice, guidance, help would be appreciated! Thanks!
http://www.civicwagon.com/showthread.php?14211-prennro-s-new-wagon&p=182593#post182593


So now have developed the dreaded irratic idle. Have experienced this and fixed this on my B-Series by cleaning and threading in the Fast Idle Thermo Valve (FITV) and/or cleaning the Idle Air Control Valve (IACV). Good trouble shooting and how-to write up here: http://www.superhonda.com/forum/f55/troubleshooting-idle-problems-259965/

Doesnt seem to have any vacuum leaks and I also made sure I bled the coolant system.

Anyway, pulled and cleaned the IACV. No change. Went to pull and clean the FITV and couldnt seem to located it! Im just wanting confirmation that my model (89 wagon DX, 2wd, D15B2, DPFI), doesnt have one and if it does (or the equivilant), WHERE IN THE HELL IS IT!?


I am assuming that with the all in one throttle body, intake plenum of the DPFI, there is an alternative sensor that may have gone bad, causing the idle issues when warm.

I am also assuming (minus the 13 hp gain) this may be one of the reasons people swap over to the MPFI, as those setups look alot more familiar to the B and D-series ive messed with.

What I pulled and thinking is the IACV is circled in red.
911.jpg

Attempted to pull the 2 sensors, one circled in orange and the other in green, but when they wouldnt easily pop out after removing the phillips heads holding the small metal plates, I left them alone.
912.jpg

Comments

  • nsticenstice Wagonist
    Have you blocked off the iacv valve, Use a soda can. If the idle stays hi and does not change when warm, its no good. Plug everything back in and clear the computer by pulling the hazerd fuse in the under hood fuse box.( i think its the one.) Then check for codes at the pcm.
  • PrennroPrennro Council Member
    I have not. Not sure what exactly you mean by using a can to block off IACV, but will look at it all again and see if the lightbulb in my head lights up. Thanks for your input!
  • nsticenstice Wagonist
    Prennro wrote: »
    I have not. Not sure what exactly you mean by using a can to block off IACV, but will look at it all again and see if the lightbulb in my head lights up. Thanks for your input!

    Just something flat to block the air from going into the iacv valve.
  • hondamatichondamatic Wagonist
    The orange and green circles are actually the fuel injectors
  • PrennroPrennro Council Member
    Prennro wrote: »
    Had a little bit of time this evening to jack up the wagon and work on replacing the passengers side axle....DONE!
    138.jpg

    Also while I was under and laying on my back, I noticed a hanging round female wire harness plug. Realized that this had been unplugged the whole time and plugged it back into the rear of the intake (see pic). Not exactly sure what sensor it is, but between that and the taped up vacuum hose I found and replaced, hopefully that fixes my idle issues!
    142.jpg
    143.jpg



    UPDATE: Blocked off the iacv per nstice's suggestion above to find the iacv working. The combination of replacing the split tubing and plugging in the unplugged harness plug has seemed to fix my idle issues.

    Thanks to all who offered suggestions!
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