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Joined: Dec 2001
Posts: 13
Junior Member
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OP
Junior Member
Joined: Dec 2001
Posts: 13 |
I was trying to find out why my wifes 96 zetec
idle would not raise with the ac on.
My haynes manual shows a idle increase sol.
mounted by the firewall.
Is this a v6 only?
Black 96 gl
mostly unchanged
except for the urge to have it crushed
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Joined: Mar 2002
Posts: 1,040
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Posts: 1,040 |
Idle Air Control (IAC) valve, attached to intake manifold on firewall side of I4, is used by PCM to vary idle speed.
Does putting a/c on affect rad fan operation?
Not sure on this point, but there maybe a difference on idle increase between atx and mtx.
98 Mystique LS v6 atx 110,000km
97 Contour LX v6 atx 125,000km
stock CD on LS, cass on LX
spoiler, tinted windows on LS only
4 wheel discs on LX only
All other available options on both
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Joined: Dec 2001
Posts: 13
Junior Member
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OP
Junior Member
Joined: Dec 2001
Posts: 13 |
This is not the iac.
I have allready replaced that.
real pain to get to!
Haynes manual calls it a idle increase solenoid.
Black 96 gl
mostly unchanged
except for the urge to have it crushed
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Joined: Mar 2002
Posts: 1,040
Member
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Member
Joined: Mar 2002
Posts: 1,040 |
The Haynes manual is unfortunately riddled with European components/systems not on our North American cars. Give me a page/figure reference and I'll have a look.
The '97 Ford manual has no such device shown for either engine.
p.s. My fan ?
p.p.s. ATX or MTX?
Edit: OK I've found it, seems to be a misnomer for the EGR vacuum regulator solenoid. Follow the vacuum hose from EGR valve and it should go to this device.
98 Mystique LS v6 atx 110,000km
97 Contour LX v6 atx 125,000km
stock CD on LS, cass on LX
spoiler, tinted windows on LS only
4 wheel discs on LX only
All other available options on both
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Joined: Dec 2001
Posts: 13
Junior Member
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OP
Junior Member
Joined: Dec 2001
Posts: 13 |
Ok. Thanks.
I knew I couldn't find it on my car.
Black 96 gl
mostly unchanged
except for the urge to have it crushed
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Joined: Mar 2002
Posts: 1,040
Member
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Member
Joined: Mar 2002
Posts: 1,040 |
Just re-read your initial post and realized your initial premise maybe wrong.
Why are you thinking idle speed should increase with a/c on?
98 Mystique LS v6 atx 110,000km
97 Contour LX v6 atx 125,000km
stock CD on LS, cass on LX
spoiler, tinted windows on LS only
4 wheel discs on LX only
All other available options on both
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Joined: Dec 2001
Posts: 13
Junior Member
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OP
Junior Member
Joined: Dec 2001
Posts: 13 |
According to the Mad Mole's page the ac pressure
switch is supposed to increase the idle to compensate for the extra load of the commpressor.
Black 96 gl
mostly unchanged
except for the urge to have it crushed
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Joined: Mar 2002
Posts: 1,040
Member
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Member
Joined: Mar 2002
Posts: 1,040 |
Read the "Mad Mole" link provided by another member on your other post. Some of the info is wrong IMO. Pressure switch contact activates hi-speed fan operation only, not idle.
PCM continually adjusts engine controls to keep idle within spec., a/c on loads engine, rpm drops PCM compensates (presumably using IAC and injector pulsing) to maintain rpm within I4 idle spec(atx 800+/-50, mtx 880+/-50).
If rpm drop by 200 PCM will shut a/c off as it attempts to avoid stalling.
98 Mystique LS v6 atx 110,000km
97 Contour LX v6 atx 125,000km
stock CD on LS, cass on LX
spoiler, tinted windows on LS only
4 wheel discs on LX only
All other available options on both
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