Idle Air control valve

Raycharles90 · Post by **Raycharles90** » 31 Oct 2012, 09:44

Hi everyone,

I am starting a new topic on my IAC but this is associated with the other thread on problems with my 98 s70 na idling poorly. https://www.matthewsvolvosite.com/forums ... =1&t=51997 I wanted to give this a new subject to get everyone expertise on the IAC. Brought it into a shop because I needed a fresh set of eyes on the problem. Called me up this morning and said that it needed a new IAC. I spoke with him and he told be that the motor was shot. Now at ~$240 for a new one I think I will head out to the pull-a-part and for $7 each I will grab a couple of them and try them out.

First question, should I be able to hear a hum or feel vibrations if they are working properly. Also, why would cleaning the IAC out improve my performance if the motor was shot?

Thanks,

Ray

Post by **jblackburn** » 31 Oct 2012, 10:40

First question, should I be able to hear a hum or feel vibrations if they are working properly. Also, why would cleaning the IAC out improve my performance if the motor was shot?

1) Yes.
2) Maybe the flap was stuck and cleaning it allows it to work a bit better.
3) Pull-a-part is a great deal. These idle air valves almost never go bad on Volvos.

Raycharles90 · Post by **Raycharles90** » 31 Oct 2012, 11:11

Jblackburn,

Thanks, hopefully I can find one or two. Looks like there are seven 850s and S series to look at. I have been there before and things get picked clean pretty quickly. I hope this does the trick.

warcraftjunkie · Post by **warcraftjunkie** » 31 Oct 2012, 11:22

Not to hijack your thread too much, but does anyone know where the IAC is located on a 1999 V70 with the electronic Throttle body? it's not in that same location as 98 and earlier V70/850... to the right of the engine infront of the throttle.

Post by **Ozark Lee** » 31 Oct 2012, 12:52

warcraftjunkie wrote:Not to hijack your thread too much, but does anyone know where the IAC is located on a 1999 V70 with the electronic Throttle body? it's not in that same location as 98 and earlier V70/850... to the right of the engine infront of the throttle.

On the '99 and 2000 it doesn't have one. The ETM takes care of the idle.

...Lee

warcraftjunkie · Post by **warcraftjunkie** » 31 Oct 2012, 13:08

That's what I was hoping you'd say. I see the part on IPD listed for the car, but haven't been able to find it under the hood.

Raycharles90 · Post by **Raycharles90** » 01 Nov 2012, 18:19

This morning I went to the pull-a-part this morning and pulled two IACs ($7 each, quite a deal). Cleaned the newer one up and installed it. I forgot to disconnect the battery while doing this. Got in and started the car up and drove around the block. By the time I got back to my house it was running rough again. Popped the hood and tapped the IAC with a screwdriver then unplugged and plugged it back in. As soon as I reconnected it the idle returned to normal. I then took it for a longer drive and it was still a little sluggish on accelerating and dropped below normal idle at a stop sign. I drove it back home and let it idle in front of my house and it seemed fine.

I have seen a couple of other posters mention "re-teaching" the car to idle/drive correctly. I can't recall off the top of my head but something about letting it idle for a bit, then driving for ~2000 rpm for a bit, etc. Is this necessary? Or, can I just reset the computer by disconnecting it for a bit?

Anybody have to deal with this?

Post by **Ozark Lee** » 01 Nov 2012, 18:31

It depends on your local smog rules. In places where you need to do an annual smog inspection (pretty much anywhere on the east coast or in California) the readiness monitors need to be set to pass the inspection. There is a drive cycle in the repair database that spells out what needs to be done to get the monitors to reset. Even when you follow the drive cycle instructions it is iffy about getting all of them to reset. If you don't need to deal that kind of crap you will find that, on your first tank of gas after making any major changes, your mileage will be terrible but after that things return to normal.

...Lee

Raycharles90 · Post by **Raycharles90** » 01 Nov 2012, 18:53

Lee,

Thanks for the information. Being in Louisiana, I don't have to worry about emissions tests. This is a good thing because the rear O2 sensor doesn't seem to be functional which causes all sorts of "not ready" messages on the code reader. I work out in an area that has a couple miles of roads with no traffic so I may play around with it.

Post by **rspi** » 02 Nov 2012, 01:17

Is it possible that my IAC is hanging open a little? My car sometimes idles a little high, around 1000 or 1100 and my gas mileage has dropped a little. I was thinking about taking it off and cleaning it up and seeing if that helps.