I just finished a head gasket job that took me 9 months, now everything seems fine except that I idles high especially in park and neutral. I get bout 1k-1.2k idle in drive and revers and anywhere from 1.5k-2k in park and neutral...when I was installing the new timing belt I had the camshaft in the tdc up position and when I'd attempt to compensate rotation of the crankshaft when releasing the tensioner puller I'd get the tdc mark about |_| that much off from the sight on the cover. I don't know if that slight space of it being off could cause it to high idle or not. I checked vaccum lines around the throttle body and everything looks good...just looking of any advice before I tear in deep to try n readjust timing belt as a last resort...thank you in advance

D16a1 engine sohc

 

D16a1? You mean D17a1?

Anyway.. check the timing. It should be 8±2° BTDC.

Check to make sure the throttle cable it's too tight, and that the throttle valve is closing all the way at idle. If it's okay, do the Idle Relearn.

Reset the PCM by removing fuse #6 from the fuse box located in the engine bay, or by disconnecting the battery. Wait a minute or so before reconnecting or reinstalling, then do A-C below.

A. Make sure everything electrical is OFF. (radio, heat/ac, wipers, lights, etc)

B. Start the engine and hold it at 3,000 RPM until the radiator fan comes on, or until the coolant reaches a temperature of 194° F (90° C)

C. Take your foot off of the accelerator and let the car idle for at least five minutes.

 

so i went ahead and adjusted the throttle cables and also cleaned all the contacts around the throttle body, pulled the fuse for a minute and reassembled everything. Car now has a check engine light which brings up a idle air control valve circuit malfunction. How could it be broken now after what i just did?

P.S. it was idling normal at start of car but every time id step on the gas pedal just a little bit it would stick to 1500+ and put out a studdering sound. IDK if taking apart throttle body and cleaning would clear up this check engine light or if u should just do a straight up replacement of the IAC valve

 

Specific code? It probably doesn't matter because it sounds like the IACV needs to be cleaned. Get a new gasket too, they're only about $4 at the dealer.

 

The PCM will sometimes hold codes without illuminating the MIL. After the reset, it may have "Hey, I'm still here." on ya.

Which code was it, anyway? I'm guessing P0511.

Is the throttle sticking? Make sure it's closing and not partially sticking open after releasing the throttle.


It might be worth taking the IAVC off and looking at the inside of it. They can get awfully nasty. Look here, for example: https://honda-tech.com/forums/honda-civic-2001-2005-78/throttle-body-clean-up-honda-civic-2001-ex-2608248/



Edit: Depending on which code it is, there may be an existing DIY floating around. Make sure your connections are good, though.

 

Yea after taking the air filter box off I noticed a plug disconnected that I forgot when cleaning some contacts��. So I plugged it in pulled the fuse to reset PCM and started her up. Started idleing good, below 1k and drove around bout 15 miles and then it started hovering a lil over 1k, so now I plan on cleaning out throttle body, iacv, and check for leaks with a carb cleaner(suggestion from a buddy at work) around the intake. Hopefully that'll do the trick. Thanks for your help guys! ��

Oh yea check engine light went away after reset of PCM and never came back.

 

Cool beans. Thankfully it was something simple like that.

Thanks for keeping the thread updated with "progress reports" too.

 

So here are some pics...hoping someone could critique the condition of my intake and throttle body and if it could cause some of the issues I'm having....also should the inside of the intake be so filthy? Thanks guys!







On the last pic, correct me if I'm wrong but that's the iacv right?

 

Heres the aftermath. Q tips are strictly from cleaning the iacv.

Gonna put on later tonight and see what happens...just reused gaskets since they still looked fine hope it doesn't cause any issues :/

 

I've seen dirtier work fine but, that's pretty dirty.

Gaskets should be fine to re-use if they look ok.

And yes, that's the IACV.