Not the IAC....

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Old 18 Sep 2004, 01:51 pm   #1 (permalink)
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Default Not the IAC....

Took my car to Firestone a couple of weeks back and had them deal with the
IAC. Even took in a post from this bulletin board explaining what the fix
was on the low idle cold starting condition. The mechanic said they used
almost two full cans of carb cleaner to spray it out until the carb fluid
ran clear. He said it was really dirty. Well it seemed to run better until
the next morning when it low idled just like before. Now (these last
couple of weeks), it never fast idles at cold start, whereas before it would
fast idle sometimes....just rough idles alot until it gets warm.

I wasn't sure exactly what he did, so I took off the intake hose and started
it up with the hose off. Fired up right away and idled nicely, heard some
clicking noises. Looked pretty clean in there, but the throttle plate
looked about the same. Bought a new air filter at Toyota just in case it
wasn't getting good air flow intake....had no positive effect. Any
ideas/comments appreciated.


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Old 18 Sep 2004, 04:11 pm   #2 (permalink)
Jason James
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Default Re: Not the IAC....


<psommerhalder@sbcglobal.net> wrote in message
news:vs%2d.17183$QJ3.4759@newssvr21.news.prodigy.c om...
> Took my car to Firestone a couple of weeks back and had them deal with the
> IAC. Even took in a post from this bulletin board explaining what the fix
> was on the low idle cold starting condition. The mechanic said they used
> almost two full cans of carb cleaner to spray it out until the carb fluid
> ran clear. He said it was really dirty. Well it seemed to run better

until
> the next morning when it low idled just like before. Now (these last
> couple of weeks), it never fast idles at cold start, whereas before it

would
> fast idle sometimes....just rough idles alot until it gets warm.
>
> I wasn't sure exactly what he did, so I took off the intake hose and

started
> it up with the hose off. Fired up right away and idled nicely, heard some
> clicking noises. Looked pretty clean in there, but the throttle plate
> looked about the same. Bought a new air filter at Toyota just in case it
> wasn't getting good air flow intake....had no positive effect. Any
> ideas/comments appreciated.


Are you saying the fault clears when the intake hose is off?

If so,..you may have the problem close at hand. Look for any obstructions in
the intake cold-air ducting from the front of the engine-bay back.

Another consideration is that the air-mass-sensor lives in the intake which
you have disconnected. This sensor tells the computer how much air the
engine is calling for, and as a result along with other sensor inputs ie 02,
MAP and TPS adjusts the mixture by the fuel injection timing.

It maybe one or more of these sensors is shagged and by effectively turning
off the air-mass-sensor (by removing the hose) the computer leans the
mixture thereby cancelling the bad info from the other failed sensor.

Just a theory. At this stage I would ask to have your sensors checked for
proper operation including the coolant temperature sensor. After-market
w/shop manuals give details on how to check some of these, but you need to
be able to operate a multimeter.

Jason


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Old 24 Sep 2004, 12:18 am   #3 (permalink)
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Default Re: Not the IAC....

Well I took my 97 Camry back to Firestone. They've been pretty great about
this.
They checked the codes and nothing came up, so they put in a fresh set of
plugs, redid a fuel injection service all under their tune-up warranty. Bad
news is that it made no difference, the low idle persists. He says that
when no codes come up, it's pretty difficult to diagnose something like
this. He recommends that I take it over to the dealership and let them
evaluate it. Could an IAC malfunction show up as a code? I have a feeling
it's just plain busted....or maybe a sensor?
This is really depressing, I'm going to have to leave it at the dealership
now for a couple of days, so it'll do it for them in the mornings...let
alone the bill I'll get. Yikes.

"Jason James" <vellicet@bigpond.com> wrote in message
news:2r3mkpF15fspeU1@uni-berlin.de...
>
> <psommerhalder@sbcglobal.net> wrote in message
> news:vs%2d.17183$QJ3.4759@newssvr21.news.prodigy.c om...
> > Took my car to Firestone a couple of weeks back and had them deal with

the
> > IAC. Even took in a post from this bulletin board explaining what the

fix
> > was on the low idle cold starting condition. The mechanic said they

used
> > almost two full cans of carb cleaner to spray it out until the carb

fluid
> > ran clear. He said it was really dirty. Well it seemed to run better

> until
> > the next morning when it low idled just like before. Now (these last
> > couple of weeks), it never fast idles at cold start, whereas before it

> would
> > fast idle sometimes....just rough idles alot until it gets warm.
> >
> > I wasn't sure exactly what he did, so I took off the intake hose and

> started
> > it up with the hose off. Fired up right away and idled nicely, heard

some
> > clicking noises. Looked pretty clean in there, but the throttle plate
> > looked about the same. Bought a new air filter at Toyota just in case

it
> > wasn't getting good air flow intake....had no positive effect. Any
> > ideas/comments appreciated.

>
> Are you saying the fault clears when the intake hose is off?
>
> If so,..you may have the problem close at hand. Look for any obstructions

in
> the intake cold-air ducting from the front of the engine-bay back.
>
> Another consideration is that the air-mass-sensor lives in the intake

which
> you have disconnected. This sensor tells the computer how much air the
> engine is calling for, and as a result along with other sensor inputs ie

02,
> MAP and TPS adjusts the mixture by the fuel injection timing.
>
> It maybe one or more of these sensors is shagged and by effectively

turning
> off the air-mass-sensor (by removing the hose) the computer leans the
> mixture thereby cancelling the bad info from the other failed sensor.
>
> Just a theory. At this stage I would ask to have your sensors checked for
> proper operation including the coolant temperature sensor. After-market
> w/shop manuals give details on how to check some of these, but you need to
> be able to operate a multimeter.
>
> Jason
>
>
>



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