Hello H-T, this is my first post so if I'm in the wrong section please let me know. So i bought my first Honda a year ago, and I've been lurking here ever since, just want to say thanks for all the advice you guys have given me, I've learned a lot from you guys. I decided to make an account finally, partially to say thanks and mostly because i wanted to share my experience over the past week or so.
quick background on my car- its a 96 civic dx, with the d16y7 and a M/T. i bought it early last year, from a 1 owner, completely stock. Other than regular maintenance,and a tune-up, all ive done to it really is some bolt-ons. So with that out the way, let me begin my story of how I learned the "if it aint broke dont fix it" moto for myself. (warning this is gonna be a long one lol)
So last week i decided to clean out my throttle body(ive got a lil too much time with all this 'rona virus causing my work to shut down for a couple weeks), so i bought some TB cleaner and a new gasket for it. So i went to work at it, disassembled the TB, unplugged all the sensors, and unbolted the IACV. I soaked it down with cleaner, even got down into the IM the best i could, used a rag and toothbrush to scrub all that dirt and grime away. I should note that i also soaked/cleaned the IACV as well.



After a couple hours i was satisfied, so i put it all back together. i cranked it up, and uh-oh, my idle (at crank, engine cold, no throttle) was around 2500 (my DX has no tach so im just guessing). My best guess was either i knocked the idle screw around, which after looking it was fine, or I had messed up my IACV when i drenched it in TB cleaner (ive heard both that TB cleaner is fine and that it'll ruin the iacv). So i got a ride to my local junkyard, found a iacv,

came home and put it on. It helped the high idle, but now i had a slight surging idle, I'd say from 750 to like 1500, not horrible, still drive-able, but annoying and probably wasting gas lol. so i took everything back apart, inspected it all, from what i could tell visually it seemed okay. So i hobbled down the street to auto-zone (1/2 mile down the road ftw), and used their handy-dandy code scanner.(I'm already throwing a code for my downstream o2 sensor). Code scanner said my TPS was bad. Knowing that those are almost impossible to install/replace/calibrate without a multi-meter etc etc, i went back to the junkyard, found the TB i got the idle valve from(note; it came off a 2000 y8 auto,which according to my service manual is interchangeable-see picture above). went home, started the process of switching them out. Now heres where it gets sticky. i had to make a couple modifications. 1st) the throttle cable rotor(?) was smaller and oriented differently, so i switched them out.

Then i had to transplant the IACV, then i touched it up with a little tb cleaner, being careful not to mess with the tps or iacv. hooked everything up, and went to crank it up. Good news-idle surge was gone. bad news- crank idle was now somewhere close to the rev limit . So i figured,naturally, being the only thing i changed was the new TB, my hypothesis was that this "new" TB was in worse shape then mine. So i, again, switched them back. Even bigger uh-oh, this had no effect on said *ugh* excruciatingly high idle. So i go back through everything, double checking that i had reconnected every hose, torqued down every bolt, plugged in every sensor. everything seemed in order.This was Friday evening, i spent all weekend, up until Monday afternoon checking everything i could thing of, researching all i could (on H-T of course ), and trying to mentally go back through everything i did. this got me nowhere. So after spending Monday morning scratching my head, i got yet another ride to the junkyard, exchanged the TB i had bought a couple days before for a TB off a 98 y7

(in hindsight i should've just kept looking till i found that one instead of just grabbing the first viable one i saw). stopped at auto-zone on my way home, got some coolant, a multi-meter, and a soldering iron for good measure. Multi meter said my tps (from my original TB) was off kilter.The new one tested fine.The new TB looked identical , so I put on the iacv, connected throttle cable, plugged in the sensors. told my accomplice i hadn't much faith this would even have a slight effect, as i was pretty much convinced it was a vacuum leak or air in the coolant system, so we would try it out, if it didn't work we pack up for the night as it was getting late. gave her a crank and what-do-you-know, shes idling near perfect now. not even a lil surge, which i would've been happy with at this point. Drove around for 1/2 hour orso, everything seems fine, even seems a lil better than before this whole debacle. So in conclusion, i spent 60 something bucks on parts, 20 ish on new fluids, bought a multi-meter,took a half dozen trips to the junkyard, lost a pair of pliers at said junkyard, gave myself a week long head ache, all to end up more or less where i was before i ever got the notion to clean the TB. and to top if all off, the TB on there now is dirty, so at some point im gonna have to clean it . I'd say I learned something from all this, but I have no idea what i did wrong, and no idea what i did to fix it, but i did it. So as they say, "if it aint broke dont fix it, or you might just break it'. take a lesson from me kiddos, dont go doing dumb things out of boredom, especially if you have no idea what you're doing and ESPECIALLY if its your only mode of transport
Thanks for coming to my Ted-Talk
PS I'm open to criticism, advice and general thoughts on what i might have unknowingly done
Just to end on a positive note, heres a nice scenic pic of my civ

 

Ehh... that wasn't a long post. I was sort of looking forward to getting lost in a meandering, stranger than fiction 5000 word post. But it was a good read. Thanks for sharing.

Your story reminds me why I don't do work on my own car and pay others to do it. Of course others don't always do a proper job, but since I'm mechanically uninclined it's worth it for me to fork over $$$ rather than muck everything up myself and become super aggravated in the process, since mechanics get it right at least 80% of the time in my experience. I once brought my '93 Civic VX to the mechanic to solve a problem where after shifting the RPM would kinda hang out before slowly dropping to where it should be. The mechanic said he cleaned the TB and when he returned the car to me it ran perfectly. I can imagine the nightmare I could have gotten myself into if I had decided to research this problem and try to fix it myself! It's an unpopular approach on a DIY site: to have someone else doing the work, but it works for me.

 

I'd have included more details if i known that was considered short lol. if i weren't so hard headed i would've just taken it to my trusted shop. also its funny you mention a hanging idle. i had that same problem today, however in my case i had just adjusted the throttle cable a lil to tight and it was just not wanting to slack up after i left off the gas. got real good at gas/up-clutch/down-(foot under gas to push it up-clutch out real quick lol.

 

One possibility on your idle issue after clean. You didn't purge the air completely from the coolant system.

It's actually a pretty common problem/error that causes surging idle.

I also am not sure how successful "cleaning" the IACV is. I haven't had the greatest luck with that and have had to keep swapping them until I get one that works. Most shops don't clean them, just replace them with new.

 

agreed on the air in the coolant. that was gonna be my next step, but then it started working right so i just topped it off. and yeah idk how much cleaning the aicv actually did,besides ruining the selenoid on it obvs.

 

get the lisle funnel.
i was losin it before i got that bad boy lol.