PwrdByVtec_EM1

hey whats up Honda-tech. im having a bit of a problem with my obd2 iacv. i recently bought one of a buddy of mine that insured me it worked, and it failed. it also gradually got worse. so the other day i bought one off some mechanic off of craigslist and the problem got better but my idle was still super high, like around 1700. he also insured me that it worked, and now its throwing a code.

could the problem be something else? like the TPI, fast idle, map giving a faulty reading causing the IACV to fail but in reality it works?

Thanks for the help.

92ehatch

year of car? type of car?

engine?

im assuming a 96-2000 ex?

bleed coolant correctly?

you arent specific enough

SeanK325

it's a b16a2 with itr pistons and aem v2.

94eg!

iTrader: (2)

Did you set the idle screw on the throttle body? If the screw is way off, your idle could be f'ed up:
- Drive the car till it's fully warmed up
- park it with the engine running
- unplug the IACV (idle drops low)
- set the idle adjust screw so the idle is at the proper range (like 450-550rpm I think)
- Shut off the car
- Plug everything back in.
- Make sure the CEL doesn't remain on

BTW: Did you try cleaning inside the new idle valves with simple green before installing them? Sometimes they get gummed up.

Also: Do you have the coolant lines hooked up to the IACV? If not, the valve won't swell at temp making the idle high like cold-start.

Are there any vacuum leaks. These allow more air into the engine causing a high idle.

Former User

This^

94eg!

iTrader: (2)

It clearly states EM1 with B16A2...

What does it matter anyways. All OBD2 Idle systems operate the same.

MeCrObS

^^^What this guy said. I just had to go though all this.

Former User

It was never clearly stated. He did eventually mention the engine, but not the car.

It may not matter to you, but it does matter when it comes to keeping this forum running smoothly. Please read the forum rules. It is the thread maker's obligation to provide all relevant car details related to the tech question. This helps the thread maker get better answers faster and avoids wasting the time of members who want to help. And it may matter in what car the OBD2 IACV is installed.

OP -- What CEL code is thrown?

PwrdByVtec_EM1

sorry for the insufficient info.

its a 1999 civic si with b16a2 with aem v2

yes, when the motor gets warm it gets worse.

and yes ive tried cleaning it but i cant get past that special 5 sides tool that looks like a hex tool. i didnt know i could use simple green. ive been using map sensor cleaner.

thanks for that great info im looking forward to trying this asap

Former User

Again, what CEL code is thrown?

PwrdByVtec_EM1

thanks for the info it seem like its gonna work

PwrdByVtec_EM1

i dont know the exact code # but it was the IACV code

Former User

There are two different IACV codes for OBD2 Civics. One is a mechanical code and one is an electrical code. Knowing which one focuses your troubleshooting.

PwrdByVtec_EM1

ohh i c.....i knew there was a mechanical and electrical part but i didnt know that it had different codes, but it only makes sense.

thanks again.

94eg!

iTrader: (2)

DANG!

Mine just threw a code 14 (obd-1 IACV) on the way to get a smog check. Go figure...

That's what I get for trying to clean it out last week...

PwrdByVtec_EM1

RPMs bogging up and down for 500 to 1900 and i when i do reset the ecu the codes clear.....when it fails and throws the code it will rev up to 1700, and with light throttle it bogs back and forth from 1700 to 1900 very quickly. I must give it more gas to rev up to normal. And if i want it to stop then i must restart the car

1999 civic si b16a2 with aem v2 intake
OBD2 IACV

Former User

Related threads merged.

What codes?

PwrdByVtec_EM1

ill post them when they come up again....i reset them because my car burns more fuel when im running on limp...this is also my second IACV and i bought it used off of craigslist. I was insured by my mechanic/buddy that the IACV he sold me would work.

PwrdByVtec_EM1

- Drive the car till it's fully warmed up
- park it with the engine running
- unplug the IACV (idle drops low)
- set the idle adjust screw so the idle is at the proper range (like 450-550rpm I think)
- Shut off the car
- Plug everything back in.
- Make sure the CEL doesn't remain on

so i went through all these steps until i came across trying to adjust my idle screw and i couldnt turn it.

At first i realized that the screw was filled with corrosion to where it was flush with the top of the screw. (flat head screw on top of throttle body)

So i scraped out all the gunk and when i tried to adjust the screw it was just chipping the screw. After i saw a few chips fly i stopped because i didnt want to strip it.

Am i adjusting the right screw?
Does it loosen and tighten in the same direction as a regular screw?

THANKS YOU.