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1993 Honda Civic D15B Idling Issues

Home Forums Stay Dirty Lounge Service and Repair Questions Answered Here 1993 Honda Civic D15B Idling Issues

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  • #435684
    EvolutionjuanEvolutionjuan
    Participant

      Hey my name is Juan and I have been coming to your videos for help on my 1993 Honda Civic. Recently I have been having some issues with idling. I have checked for air in the cooling system and even cleaned the Idle Air Control Valve that is located directly under my throttle body. I also cleaned the throttle body with carb cleaner and screwed down the mechanism that lets the air in, all the way down but loosened it a bit and installed it back but my idle now seems to sit at 1000rpm-1200rpm. So when my idle jumps it goes from 1000rpm-1500rpm. Also when I give the car gas the rpm’s raise then drop below 1000rpm to almost sounding like the car will shut off like its choking or something. I just noticed that my muffler needs to be replaced for the reason that the pipping that connects to the muffler it self has cracks and can now move in and out of the muffler inlet. Would that cause my idle issues? I have not taken off the Fast Idle Air Control Valve that sits on the intake manifolds front towards the firewall. This is the valve that has the screen in it and only has two bolts that hold it in place. Should I take that off and clean that? What should I check and or do first? Thank You for your time and hope to hear back from you soon.

    Viewing 15 replies - 1 through 15 (of 40 total)
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    • #435687
      EvolutionjuanEvolutionjuan
      Participant

        @College man: thanks for the vids will try and do that.

        #435688
        MikeMike
        Participant

          You dont need to remove fuse…just disconnect battery….wait 30 minutes…then reconnect battery and let idle for 10 minutes…then i would drive it around for about 15 minutes or so

          #435689
          MattMatt
          Participant

            Eric’s Honda idle speech:

            http://www.ericthecarguy.com/search.asp … h&ff=false

            Have fun! Good luck.

            #435685
            college mancollege man
            Moderator

              I’m going to give you a couple videos to help guide you with the issue your having.C8-)

              http://www.youtube.com/watch?v=L788jKEV … plpp_video

              http://www.youtube.com/watch?v=9CPqbaSg … plpp_video

              #435686
              MikeMike
              Participant

                Have you checked for vacuum leaks?

                #435690
                EvolutionjuanEvolutionjuan
                Participant

                  Hey I recently cleaned the screen on my Fast Idle Air Control Valve and that seemed to have taken away my surging idle. I still have an issue with my idle being stuck at 1000rpm-1200rpm though. I tryed looking for vacuum leaks using carb cleaner like Eric did in his vids but nothing. Is it normal for a honda to be idling at rpm’s of 1000-1200. Before I even touched my engine my car would idle normally at around 500-800rpm but with the surging idle. I first took of the idle air control valve that is underneath the throttle body which has the wax pellete that u need to screw all the way down in which I did but after install and start of my engine the rpms stayed at 1000-1200. Could it be that I need to loosen the plastic screw type mechanism? Is having my rpms as mentioned really bad/not good for my car?

                  #435691
                  college mancollege man
                  Moderator

                    Lets review. You screwed the fast idle screw down all the way. (2) You banged on the IAC with the screw driver handle
                    as Eric showed. no change. (3) You searched for vacuum leaks none found. (4) did you mess with the base idle screw
                    on the throttle body? does it still have the factory sealant on it?C8-)Your coolant is full and free of air. Do you have a check
                    engine light on? If so post code. Try using water and a spray bottle to search for vacuum leaks. spray all gaskets and hoses
                    including air tube

                    #435692
                    EvolutionjuanEvolutionjuan
                    Participant

                      I did mess with the base idle screw but it doesnt matter if i totally unscrew it the rpm’s stay at 1000rpm it isnt untill i apply pressure to the throttle body mechanism to give it more gas but i turn it to let less air in and that when the rpm’s drop. No check engine light. My coolant is full and no air. I guess the only thing left to do is a tune up, search for vacuum leaks, do a ecu idle learn reset, and well replace my muffler as mentioned previously. Do you think my muffler being shot would have anything to do with my idle? Before I messed with the screw on the idle air control valve that has the wax pellete my rpm’s were around 500-800rpm. What if I unscrew the wax pellete to about half way from fully tight to really loose? I understand the tighter means less air but its worth a shot.

                      #435693
                      college mancollege man
                      Moderator

                        first according to Eric that base idle screw should never be touched. set at the factory. The fast idle with the wax pallet should be all
                        the way in.I think the base idle screw adjustment is part of your problem. when the car is fully at operating temp.try to adjust that screw
                        a little bit to get the idle down. you might also try putting your finger over the IAC hole in the throttle body to see if the idle changes.
                        if it does you may have an IAC problem. also spray the water on and around all the stuff you removed for vacuum leaks. also
                        spray the cracked piece you talked about.

                        #435694
                        JDM_Hatch99JDM_Hatch99
                        Participant

                          No its definitely not normal for a civic to idle at 1000 RPM at temp, 750 is more like it. Have you tried cleaning out your intake manifold and throttle body? Maybe theres gunk in it that is keeping the butterfly partially open.

                          #435695
                          hbvxhbvx
                          Participant

                            I believe the fast idle valve is more relative to start and cold starting issues. It may also be relevant to elevation above sea level, as far as symptoms with it.

                            Your Fast Idle valve is the one under the throttle body with the wax pellet and your IACV is the one mounted onto the intake manifold. You are supposed to check the screen on that one, it has coolant lines running through it. That is one reason why air in the cooling system could cause a hang up, usually the IACV is notorious for raising/falling idle at times, you ‘could’ try removing it to check the screen/perhaps clean it out, be sure to bleed the cooling system.

                            You should not adjust your base idle screw as this is only covering up another issue. Perhaps this could be a TPS sensor issue, but IDK, is this a M/T or auto? If you know how to test the wires to various sensors, always worth a try, but go over all steps before replacing parts.

                            Since you are trying to find the cause, you need to now reset the base idle screw before going forward, IMO. The factory service manual gives step by step how to do this and it does matter if you have an auto or a stick. If the screw is out too much, it may be acting as a vacuum leak, for example and fooling with the control valves is pointless until they can adjust a correct base idle.

                            #435696
                            dreamer2355dreamer2355
                            Participant

                              The links College Man and Beefy posted should be all the information you need to know to help with this idle issue, particularly Eric’s idle speech.

                              You could sweep test the TPS along with checking your throttle linkage to see if there are any kinks or to see if its in a bind.

                              #435697
                              EvolutionjuanEvolutionjuan
                              Participant

                                If I loosen the screw on the throttle body the rpm should be going down but it doesnt. The butterfly in the throttle body is completely closed but I might take it off again and clean it again. If I tighten the screw on the throttle body the rpm rises and I need it to go down not up lol. My idle does not jump anymore as previously mentioned it just stays at around 1000rpm when warmed up. I will try to cover some of the holes with my finger and see what that does. Would my idle at 1000rpm effect my chances of passing smog? From my opinion the idle at 1000rpm is only at that when idling but if your driving around in the car does it really make a difference? I recently was driving the car and I checked how easy or hard it was to stall the car from neutral to 1st gear. O yea its a manual. Anyways my car is pretty hard to stall unless u want to do it purposely. My throttle linkage isnt tight it has a bit of play but not to much. I did also take the fast idle control valve that has the screen and cleaned that too already. It was extremely dirty along with the plate that has the 3 screws that was covered with like a film of gunk. I havent cleaned my intake manifold, im kind of iffy about that because its attached to the engine with the bolts and I really dont know the torque settings on that and wouldnt want to mess up anything. If its just removing bolts and putting it back on with just tighting the manifold then I am able to do it but torque settings would be sketchy for me. My tbs that is on top of the throttle body is cracked but I sprayed carb cleaner on it and my rpm stayed the same along with other hoses. One thing I noticed was when i took off the intake itself and turned on my car the throttle body was sucking so much air in it was making like a hissing noise which I thought was a vacuum leak now i know its supposed to breathe in air but should it be making that hissing noise and I actually put my hand on the mouth of the throttle body and it sucked my hand so air is passing threw. The only issue now besides the cracks in my muffler as mentioned above is my rpm being stuck at 1000rpm.

                                #435698
                                EvolutionjuanEvolutionjuan
                                Participant

                                  I also read somewhere that when cleaning out the throttle body u should try not to remove/clean off this sort of painted ring around the butterfly which in turn lets less air in? Anybody know about this or know if it matters or not? Also like I mentioned if I push on the throttle spindel type thing that has the throttle cable attached to it even tighter to were it lets less air in I can make the rpms go down because the engine is breathing less air but should that be messed with? I also tryed to go to my local Autozone to get the idle air control valve that is located underneath the throttle body with the wax pellete in it and they couldnt find the part because it wasnt under idle air control valve. Does it have another name for it? I think im also going to pick up another throttle body gasket because the one i have might be worn out or letting air in perhaps.

                                  #435699
                                  hbvxhbvx
                                  Participant

                                    ^Please, re-read my post.

                                    You have the two valves confused. Hissing at the throttle plate/throttle body may be normal or it could mean you still have a leak at the adjustment screw.

                                    You need to start by adjusting the base idle correctly, that involves disconnecting some other things, not simply turning in the screw until the idle is where you think it should be. You need to look at a Factory Service Manual or a Haynes book, Chilton’s online may have the procedure to resetting the base idle screw to factory norms.

                                    The issue with running at 1,000 RPM at idle is you don’t know the reason, for instance a vacuum leak, it does affect things like fuel economy, etc. Having to dump in more fuel to compensate for increase air intake, which could lead to HC emissions problems or other issues, as a vacuum leak alone.

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