would the IACV cause my car to sputter and bog during freeway cruising? i have a good feeling it is failing because my idle isn't stable at all for one so, i'm not sure if that failing piece would cause problems with driveability.

i suspected the TPS but it isn't throwing any codes at all.

 

the idle could be one thing, but a while back i had a similar problem with bogging during freeway crusing and it turned out that some leaking unburnt coolant from my leaking head gasket got on my 02 sensor and destroyed it (coolant destroys o2 sensors). im not saying that is what it is but my best advice if you havent already just check the code and it will tell you what is wrong.

ps- a more common symptom of a failing iacv is that of a surging idle.

 

Yeah, IAC will make your idle go up and down in a patern, shouldn't have an effect on bogging unless there's a leak where it bolts onto the intake manifold.

 

It should not really affect you on the freeway. It affects the idle, hence Idle Air Control

Symptoms are idle going up and down during idle. You will also throw a code 14 check engine light. Jump the service connector to read the code.

To test it, idle the car at normal operating temp. Then pull off the 2 prong harness in the bottom of the valve. If the engine does not lower in idle or stall, you need to replace it or:

Take the IACV off (2 coolant lines and 2 12mm bolts), get some carb cleaner, spray the sumnabiatch out like crazy to get all deposits out causing it to clog.
Reconnect it and see if that helps you.

Goodluck and hope whatever I said helps are "learns" you something new today

Edit: I can get you another working IACV if you need.


[Modified by intekragsr, 10:30 PM 3/30/2003]

 

thanks for your guys' help.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by intekragsr &raquo;</TD></TR><TR><TD CLASS="quote">To test it, idle the car at normal operating temp. Then pull off the 2 prong harness in the bottom of the valve. If the engine does not lower in idle or stall, you need to replace it.</TD></TR></TABLE>

So your saying if it doesnt lower or shut off its a bad IACV?My idle was surging and he unplugged it and it idle'd perfect.Later on when i tried it,the engine shut off.I have a 92 civic hb with a poor mans R.I have an ITR manifold with odb-2 IACV because the bolt pattern was different than my odb-1 iacv.

 

Just because your idle surges, or you get a Code 14, it does NOT mean that your IACV is bad. Lets say for example that the ECU commands the IACV to lower the idle, but the idle doesn't go any lower: when the ECU commands a device, it expects something to happen, and when that something doesn't happen, the ECU thinks that the commanded device is bad.

Well, what effect does a vaccum leak have on our engines? It serves to raise the engine rpm...just like depressing the throttle. Our ECU's also have a "decel fuel cut" strategy that saves us some gas. When the engine rpm is over ~1300rpm, and the TPS is reporting that the throttle is closed, the ECU cuts off the injectors. As you can see, if you had a vaccum leak that raised the idle above 1300rpm, and your sitting at a stop light with your foot off of the throttle, the ECU is going to want to cut off the fuel injectors...and hence the surging idle.

A lot of blame is placed on the FITV (fast idle thermo valve - which not all engines are equipped with) as this is an all-mechanical valve that helps out with cold idle. Basically a wax element sits in coolant, and as the coolant heats up, the wax expands which pushes a 'plunger' against the passage that was previoiusly allowing additional air to bypass the throttle plate. This device tends to become lazy over time and does not seal the air passage as well when the engine has fully warmed up....so it becomes a source of unmetered air, or a vaccum leak. People who do swaps will sometimes neglect to connect up the coolant lines to the FITV. The common fix for that was removing it, taking off a plate which exposes a ring that you can screw in which basically disables the FITV....not a good thing for people in cold climates, but a fix no less.

So, could your IACV be bad...its a very real possibility. They do tend to get gummed up, and as a previous poster suggested, remove it, and clean it hella good....only costs a bottle of TB cleaner.

 

great info guy.... OT: but here is my problem

2000 civic ex
B18c1
skunk2 IM install gone bad

we took off the stock GSR IM, plugged all sensor and coolant lines carefully.
Reinstalled the TB, sensors, and fuel rail bolts, ect to the new SKUNK2 IM.
Installed a new IM oem gasket and TB gasket.
pluged up everything accordingly.
-no leaks in any vacume lines
-checked other buddies car who had ek and itr/b16/skunk2 style IM if we ran the vacume lines correctly (checked about 3 cars just to be sure)
Me and pennie_hatchie belive that everything is done correctly.

Car starts up and has a bouncing idel from 1500 to 2000rpms also running in LIP mode and <U>can't rev past 3,000rpms fuel cut off.</U> the car also seems to be running rich and is somewhat back firing during bouncing idel.... HELP

could it be a bad IACV?

 

this could be a case of mixing up your map and tps connectors, i did this once with a manifold way long time ago, try switching those connectors (as they are the exact same connector and color).

after that try tightening down your 12mm manifold bolts some more, the torque spec says 20lbs but i tend to do a bit more than that after letting the head warm up.

-sander

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Charlie Moua &raquo;</TD></TR><TR><TD CLASS="quote">great info guy.... OT: but here is my problem

2000 civic ex
B18c1
skunk2 IM install gone bad

we took off the stock GSR IM, plugged all sensor and coolant lines carefully.
Reinstalled the TB, sensors, and fuel rail bolts, ect to the new SKUNK2 IM.
Installed a new IM oem gasket and TB gasket.
pluged up everything accordingly.
-no leaks in any vacume lines
-checked other buddies car who had ek and itr/b16/skunk2 style IM if we ran the vacume lines correctly (checked about 3 cars just to be sure)
Me and pennie_hatchie belive that everything is done correctly.

Car starts up and has a bouncing idel from 1500 to 2000rpms also running in LIP mode and <U>can't rev past 3,000rpms fuel cut off.</U> the car also seems to be running rich and is somewhat back firing during bouncing idel.... HELP

could it be a bad IACV? </TD></TR></TABLE>

While engine is running pull the connector to the IACV, and if the engine bogs out or stalls, then the IACV is working. But if the engine continues to run without interuption then you have a bad IACV.

 

thanks guys.

I'll test that out and also check to see if I mix up the map and IACV sensor.

 

I just replaced my IACV today, and it didn't fix my reving problem...I guess I will replace the FITV as suggested by EE_Chris a long time ago.... I knew I should have listened...

 

where's the IACV located at on a GSR head?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lo0nY &raquo;</TD></TR><TR><TD CLASS="quote">where's the IACV located at on a GSR head?</TD></TR></TABLE>

It's on the back of the Intake manifold

 

where does it look like? and is that the only sensor behind the gsr manifold?

 

anyone?

 

here's a pic of it. im selling one on ebay.

http://cgi.ebay.com/ebaymotors...46416

 

Ok. So that's the IACV. How would I go about cleaning it?

My idle goes up and down from 900rpm to 1500rpm a couple times until it settles to 900rpm. Once I rev it up or start moving again, then letting it idle, it does the same thing. It fluctuates from 900rpm to 1500rpm until it settles back down to 900rpm and stays there.

After driving for awhile and idling, my rpm will shoot back up to 1500rpm and stay there while the CEL #14 pops up. It tries to go back down, but it seems like the car (or the sensor) won't let it go lower than 1500rpm.

At this point, I just turn the car off, and when I turn it back on, the idle is ok and does the fluctuation again until it settles back to 900rpm. I just reset the ECU and drive around for a couple days until the same thing happens later on.


What should I do first to solve this problem?

 

that's what happen to my friend ek, we just replace the IACV and everything was cool. on my car something similar happen but i found out that it was my jdm itr cluster gauge that the cause of it. i just simply put back my stock cluster and it was fix.

 

hmmm I have a similiar idle problem but its done it since Ive used my auto P08 (code 19) could this have anything to do with it or do you think my iacv just happpend to go now?
thanks
John

 

bump

 

hmmmmm, i always thought a Vacuum leak will make the car stall or stumble.....not idle up? all the engines i fixed you spray TB cleaner around suspected area and the idle will increase when TB cleaner is sprayed.