i.

car is a 2000 ex, swapped with a 2000 b16a2, still obd2.
im throwing a iacv code (14) an a catalytic system code (67). (i believe the code 67 is cause the cat is pretty much free flow and both 02s are reading the same; not getting any o2 codes, i dont think the codes are related, ive had the 67 for a while now.)

the problem is that when i approach (normal driving) shift point, the car bucks, and when im in any gear, say 4th @ 45mph, and ease off the gas, it does the same, and when i try and ease back on the throttle, like to speed up a little, the acceleration kicks. cant get it to accelerate smoothly unless i drive kind of aggressively. this problem happens only intermittently, when it does happen, if i park the car for a couple hours it drives fine. sometimes it happens again, sometimes i can go a couple of days without it coming back.

im throwing a iacv code, but the car idles fine in neutral. the only odd thing is some times the idle is 500 above normal but still smooth. i've cleaned the iacv screen and coolant passage with brake kleen, idk if that helps though. i've also tried another iacv and the problem still comes back. possible that i got another bad iacv? or is there something related that is causing the code 14 to show up?

pretty much all the underhood maintenence has been done, timing belt, thermostat, water pump, fuel filter all changed about 5000 miles ago. cap and rotor, plugs, oil, and filter changed earlier this month.

looking for opinions on this, troubleshooting i havent done, hopefully someone has had the same problem and knows what to do. idk how the iacv works, or if it can be cleaned or taken apart or whatever.

thanks for any help.
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UPDATED
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So i've tried a 2nd ecu, stil the same, finally got a new IACv from Honda.
It still does the same thing, (reset the ecu) and it still throws code 14. Buddy of mines thinks its not the IACv, even though im throwing the code for it. Because the problem is the acceleration, always around 2000 rpm's. (it jerks hard, just like someone who is learning to drive manual and is having trouble letting the clutch out after shifting)
The only idle related thing i notice is in neutral, (like at a stoplight) the idle is between 1300-1400. sometimes it drops down to normal (1000), but usually not.
also, as far as for the kicking (at higher speeds) when trying to maintain a cruising speed (60-65mph) theres seems to be no throttle response right at the beginning when im starting to apply pedal pressure,for like a half second. then it kicks.

I dont know wtf is going on. i hope i can return that new iacv. what else can i check?


Modified by i. at 11:23 AM 10/16/2007


Modified by i. at 11:35 AM 10/16/2007


Modified by i. at 11:35 AM 10/16/2007

97Ej6mike

This is a very strange problem that ive run into myself after my swap, almost thought it was TPS related, even tho the ECU throws a CEL for the IACv. I cleaned my FITv and replaced my IACv and it hasnt bothered me since.

I did have a friend tho who had the same issue, said F*ck it, and replaced the entire intake manifold, and never saw the problem ever again. Being it was solved by that, i would say its TPS related, cause a new IACv didnt work for him, new FITv didnt work for him... i mean, wtf, why would the ECU throw a CEL for IACv?? Its beyond me, so i assumed it to be a TPS problem, based on its symptoms, regardless of what the ECU was saying.

i.

i have also heard that this problem happens a lot in EK swaps. i haven't tried to clean the fitv. i also am starting to think that its something else beside the iacv, even though its throwing the code 14.

vrrodri

measure the ohms on the IACV connectors and see if you get a normal reading, if not, your IACV is bad.

i.

never thought of that. what would a normal reading be, or where could i go to find it. tried a search, no luck.

i.

havent gotten a change to meter the iacv yet, but i swapped out the ecu just to rule out the possibility that my ecu is bunk.

any other suggestions?

Duane_in_Japan

TPS is related to the IACV, they are both on the throttlebody, if the throttle plate is dirty and not closing properly and letting in too much air OR if the throttle plate is dirty and not letting in enough air the IAC has to compenstate for both of these scenarios and the ECU knows this and may set a code for the IAC for being out of range while the real issue was a dirty throttlebody. Lets say you did not clean the throttle plate but you cleaned the TPS by removing it and reinstalling it, this is where you disturbed the dirt on the throttle plate and inadvertently fixed the issue at hand and the IAC is more within range than before and will not throw a code now. Many times you do not have to actually erase a code to make it go away, if the ECU sees the fix it may very well clear the code for you, some systems take more drive cycles than others.

vrrodri

A repair manual will have the OHMs range for the IACV, look what it is for your engine and test the resistance on the IACV.
Mine is shot so I ordered a new one...

i.

thanks for the advice an suggestions guys. didnt think to check the tps or throttlebody. if it continues to do it again with the other ecu, then i will try and rule out the resistance on the iacv and clean the tps/tb.
kinda hoping i wont have to get a new iacv, i called honda yesterday, that thing is $280!.

Duane_in_Japan

An ohm test to me is only a test, is it way off base or do I need to do a different test if its in spec, I dont like ohm tests but I own my own portable scope, I feel sorry for guys who chase their tails on ohm tests, but what can you do.

vrrodri

if you do not get a correct ohms reading on it, it is broke, no guessing about it.

i.

so an update...
after a fweew days running the second ecu, the problem resurfaced. with the 2nd ecu, it still threw the same code (14) the idle was off between 300-500 high, but the car accelerated normally.
the only thing out of the ordinary was that the problem started again right after a nitrous run, 75 shot.
i think i might have to suck it up an get another iacv from honda.
anyone got any other ideas to try before i drop 280 on a new one?

i.

UPDATED FIRST POST, PLEASE LOOK AGAIN.

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UPDATED
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So i've tried a 2nd ecu, stil the same, finally got a new IACv from Honda.
It still does the same thing, (reset the ecu) and it still throws code 14. Buddy of mines thinks its not the IACv, even though im throwing the code for it. Because the problem is the acceleration, always around 2000 rpm's. (it jerks hard, just like someone who is learning to drive manual and is having trouble letting the clutch out after shifting)
The only idle related thing i notice is in neutral, (like at a stoplight) the idle is between 1300-1400. sometimes it drops down to normal (1000), but usually not.
also, as far as for the kicking (at higher speeds) when trying to maintain a cruising speed (60-65mph) theres seems to be no throttle response right at the beginning when im starting to apply pedal pressure,for like a half second. then it kicks.

I dont know wtf is going on. i hope i can return that new iacv. what else can i check?

Duane_in_Japan

I believe the jerking is a tranny problem. Can you adjust the idle down with the idle screw on the upper corner of the throttle body with a common screwdriver, thin and wide.

97Ej6mike

Man, this is exactly what ive gone thru, its a mysetery problem, lol.

Keep in mind that the IACv has small rubber o-rings that help seal it, they can become faulty over time. They can degrade to the point of a vaccum leak, which may cause the iacv to do funky things, just a thought tho. Also make sure your intake manifolded is bolted tightly, and that there are no vaccum leaks.

Im concluding that it must have to do with vaccum, because the last time it happened to me, i noticed when the problem started that my vaccum guage dropped oddly, from a normal rate of about 23-24 (HG.cc?) to around 19, which is not a normal reading. It does feel TPS related tho, when you get no response from the gas pedal for about 1/3 of its distance, then finally having it kick on and sound like a slow 2-step lope.

i.

im thinking it might be vacuum related as well. the idle surges slightly, about 300-400 rpms. usually when i come to a stop, the idle will drop to 1000, then up to 13-1400. sometimes it stays around there, other times it goes gradually to 1000.

97Ej6mike - how did u fix your problem?

97Ej6mike

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by i. &raquo;</TD></TR><TR><TD CLASS="quote">im thinking it might be vacuum related as well. the idle surges slightly, about 300-400 rpms. usually when i come to a stop, the idle will drop to 1000, then up to 13-1400. sometimes it stays around there, other times it goes gradually to 1000.

97Ej6mike - how did u fix your problem? </TD></TR></TABLE>

Well i ended up replacing the intake manifold as it was, not directly cause of that problem, but cause i had the wrong manifold. When i did tho, i made sure it was bolted down tightly, no leaks. I also double checked all my vaccuum lines, and As for the IACv, as i mentioned before, it has small rubber o-rings that can be replaced that help seal it right. Since then, i have not seen the problem return.

jasoncrashtech

this thread is such a common problem. i've had to try explain this to several people. nice topic and good knowledge

i.

So i finally fixed it!
Got lucky since i had access to a snap on scan tool, which was super impressive btw.

turns out my tps was off, and needed to be reposistioned to 10% with the throttle closed, and the idle was set too high, had to bring it down almost 300 rpm's.
cars runs perfectly fine now.

thanks for all the help an advice guys, an i think some of these (idle/iacv) threads need to be combined an put into the faq's...