Hoses on an IACV

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

Dan Peduzzi - 07 Mar 2006 19:46 GMT

I have a '99 Integra LS which has been giving me performance problems for
a little over a year now. One of the problems is an erratic idle which I assumed
was caused by a bad IACV.

Well, I replaced the IACV with a brand new part from the dealer a few months
ago. Unfortunately the problem didn't go away, and my car has been limping
along ever since.

But today, I revisited the IACV. When I detached the two hoses, fluid spilled
out of BOTH of them. My understanding is that one of the hoses carries coolant,
and the other carries air. Am I wrong about this?

I'm wondering if maybe the old IACV leaked, and there was fluid trapped
in the air hose which I never (and should have) drained out.

Thanks for any ideas!

Reply to this Message

TeGGeR® - 08 Mar 2006 00:29 GMT

> I have a '99 Integra LS which has been giving me performance problems
> for a little over a year now. One of the problems is an erratic idle
> which I assumed was caused by a bad IACV.

"Erratic" in what way? Describe in detail, please.

> Well, I replaced the IACV with a brand new part from the dealer a few
> months ago. Unfortunately the problem didn't go away, and my car has
[quoted text clipped - 4 lines]
> hoses carries coolant, and the other carries air. Am I wrong about
> this?

Yes. They *both* carry coolant. One hose is connected to the pressure side
of the cooling system, the other to the suction side. Fluid flow is
positive through them on account of the pressure differential.

The purpose of coolant flow through the IAC is to warm the IAC so it won't
ice up.

> I'm wondering if maybe the old IACV leaked, and there was fluid
> trapped in the air hose which I never (and should have) drained out.

Unlikely for blocked flow unless there was lots of goop in the lines.

Signature

TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Reply to this Message

Dan Peduzzi - 08 Mar 2006 01:42 GMT

>> I have a '99 Integra LS which has been giving me performance problems
>> for a little over a year now. One of the problems is an erratic idle
>> which I assumed was caused by a bad IACV.
>
> "Erratic" in what way? Describe in detail, please.

After starting it cold, it seems fine for about 5 minutes...then the RPM's
starting jumping between 1500 and 2000, about once per second. This happens
in park and neutral.

The RPMs seem fine in drive, but when I'm decelerating down to a stop, there is a
noticable and jerky "drag". Sometimes the CEL is triggered, but the codes don't seem
to help the dealer at all...I've had it there 3 times and been given 3 different explanations
(need new air filter, need IACV, etc.) none of which has solved the problem.

I replaced the throttle position sensor myself, based upon info I got from a garage other
than the dealer. That didn't do it. I'm hesistant to bring it back to the dealer again because
it seems like I'm paying them money to scan codes, but not fix the problem.

>> When I detached the two hoses, fluid
>> spilled out of BOTH of them. My understanding is that one of the
[quoted text clipped - 7 lines]
> The purpose of coolant flow through the IAC is to warm the IAC so it won't
> ice up.

Thanks for straightening me out on this. I thought I was on to something. :-(

One additional piece of information I can give is that when the idle is "bouncing"
and I disconnect electrical connection to the IACV, then the idle becomes
steady.

Dan

Reply to this Message

TeGGeR® - 08 Mar 2006 02:46 GMT

>> "Erratic" in what way? Describe in detail, please.
>
[quoted text clipped - 5 lines]
> there is a noticable and jerky "drag". Sometimes the CEL is triggered,
> but the codes don't seem to help the dealer at all...

What were the codes? Please report.

>> The purpose of coolant flow through the IAC is to warm the IAC so it
>> won't ice up.
[quoted text clipped - 5 lines]
> is "bouncing" and I disconnect electrical connection to the IACV, then
> the idle becomes steady.

Interesting. The IAC is evidently attempting to adjust the mixture by
adding air, but when the revs get too high with the throttle closed, it
shuts off the air and the revs fall. This appears to mean the ECM is
receiving incorrect information from some sensor somewhere.

When you disconnect the electrical feed to the IAC, what does the idle
stabilize at?

Has the idle speed been correctly adjusted?

What were the error codes you received?

How's your gas mileage?

What happens when the car is well and truly warmed up? Are you having
trouble getting it to heat up like it used to?

Signature

TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Reply to this Message