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IsaacCarlson 07-05-2010 07:49 PM

I unplugged the idle air bypass
The truck has been wanting to rev a little high between gears and idles high at stop signs every once in a while. I pulled the wire about 5 minutes ago and it idled nice and low the way I like it. Now to test it out.....HMMMM I have a friend that needs brakes done....maybe I will take the truck.

IsaacCarlson 07-05-2010 11:21 PM

......AND GOT 32MPG!!!! I drove from Colfax to Eau Claire and back for a total of 55.xx miles and used approximately 1.7 gallons of gas. I even made an extra stop to help someone who hit a deer(the deer was a complete loss) and had to take off up hill. I have to go back tomorrow so I will see if it comes out the same again. The rpm drops right down to idle between shifts so it enters the next gear perfectly. It idles like silk.
I also plugged the EGR back in....not sure if it works or not but it is plugged in.

RobertSmalls 07-06-2010 12:35 AM

IACV's are annoying, and they're not needed for a smooth idle above a certain engine temperature. In my case, it's around 100F. You'll probably want to leave yours unplugged until autumn rolls around. I've thought about an IACV toggle switch, but the engine kill switch sort of makes that redundant. 0RPM > 1000RPM. :)

tasdrouille 07-06-2010 08:30 AM

I need to do that to the Elantra. Oh, how I like seeing it rev to 2k rpm as I turn the key on a chilly winter morning! :rolleyes:

320touring 07-06-2010 09:01 AM


Originally Posted by tasdrouille (Post 182440)
I need to do that to the Elantra. Oh, how I like seeing it rev to 2k rpm as I turn the key on a chilly winter morning! :rolleyes:

My Parents Toyota Avensis (97 year model) does this- it holds 1500 for about 30 secs after start up- seems to be an inbuilt way of getting the engine toe temperature quicker..

has anyone compared the time and fuel required vs not having it?

comptiger5000 07-06-2010 10:22 AM

My Jeep isn't too bad with the IAC. It revs to 1500 and settles right back down on startup (when cold, about 1200 when warm). I think my coolant temp sensor is reading too warm though, as it doesn't do the 900 rpm cold idle that it's supposed to unless it's below 30* when I start it. If I fire it up on a 60* morning, it drops right to normal curb idle (and yes, the IAC works).

dcb 07-06-2010 10:59 AM

The saturn was annoying on restart, like it would jump to 1800 rpm for a couple seconds.

I just waited till it was warmed up with some accessories on and idling nicely, and unplugged it. I don't need the engine to rev up every restart (which is a lot)

Dr. Jerryrigger 07-08-2010 03:31 AM

My Subaru jumps up to 2,200RPM (2,000 before i used synthetic) and takes about 90sec to drop to 1000, and it idles at ~600. I really should do something about that.
My ex has a dodge Dakota with a busted IACV. It had a broken vacuum hose, so I replaced that, but that only helped the vacuum leek. It would stall out now and then if you didn't have a feel for when it needed a little air. Once it stalled in the middle of a bad intersection, but I kept it rolling as I popped into N and cranked it. I can see why cars have them, but I don't want mine to :p
Any CEL reaction to the unplug-it approach? It seems like such a simple thing that it wouldn't.... well maybe on a 09 or 10 (but I will not be driving one of those for a least ten year)

comptiger5000 07-08-2010 09:20 AM

In my Jeep, unplugging the IAC is an instant CEL. When you plug it back in, the light clears after 2 or 3 drive cycles.

RobertSmalls 07-08-2010 10:56 AM

Dr. J: Let us know if the Subaru throws a CEL.

You should be able to create a fake IACV for the computer to look at. If you don't want to spend a bunch of time at RadioShack, then you could just zip-tie a junkyard IACV next to your throttle body and plug in to that for the summer.

Or perhaps you could create a restriction in the IACV air passage. Be careful that your restriction doesn't get sucked into the engine; the pressure across a throttle plate is enormous.

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