1989 Toyota Other Idle-up magnet valve for AC

Tiny
EMMCEEZ
  • MEMBER
  • 1989 TOYOTA
  • 2.0L
  • 6 CYL
  • RWD
  • AUTOMATIC
  • 120,000 MILES
This is a long story, so bear with me.

Does anybody have a airflow diagram for an idle-up magnet valve, or alternatively, explain how the flow works with AC off and with AC on.
The diagram attached is a Toyota Magnet Valve and Diaphragm

If I follow the pipe connections as per diagram, the outer pipe with the one way valve attached, connects to the outside of the diaphragm with the other end connecting to the 1st pipe (outside) of the idle up magnet valve
It appears that the airflow comes from the diaphragm to the IU only when the AC is switched on

The second pipe connection as per diagram runs from the inside pipe of the IU and connects with the body on which the diaphragm is mounted. This particular connection on the body sucks air even when the AC is off.

As both of these units have just been replaced with OEM parts, I'm still experiencing engine stalls on cold starts. When the Ac is switched on, even after adjusting the idle speed.

Normal idle speed is 700Rpm without AC. Turning on the Ac at idle will bring the RPM up to 1200 for a few seconds, then settles at around 900RPM. But if I cut-off the AC at idle, the RPM will drop to around 400 and the engine will stall.

I have checked all the connecting pipes for cracks, and they are OK. Mostly they are new pipes.
I have checked to see that the one way valve in the IU pipe is properly connected, and it's also OK


The first thing I need to know is, have I got the pipe connections right. It would be useful if I knew how the airflow is supposed to work with and without the AC

Hope somebody out there has a solution. Just keep in mind with your answers I'm no techie mechanic, just a DIY learn as you go guy, so simple answers please.

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Wednesday, December 10th, 2014 AT 9:07 PM

11 Replies

Tiny
MHPAUTOS
  • EXPERT
Before going to far into this I need more info, what model and engine code, normally Toyota on early engines used a vacuum bleed idle up valve, there was a VSV (vacuum switching valve) on the fire wall with the A/C on this valve activated and supplied vacuum to a idle up valve on the inlet manifold, this allowed by pass air into the manifold and raised the idle speed. But I need to know engine code as you say it a 2 litre and a V6 which to my understanding is not an engine they used.
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Thursday, December 11th, 2014 AT 1:02 AM
Tiny
EMMCEEZ
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Many thanks for the follow-up.
Firstly, please refer to the attached images of OEM parts and engine compartment

The engine is a IGFE (this was switched from a 1GGE original) and the Model is E GX81 ATPQF original JDM, but now fitted with the IGFE engine.

It has a Vacuum sensor for the EFI mounted on the firewall

Hope that provides enough info for you.
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Thursday, December 11th, 2014 AT 1:55 AM
Tiny
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There are no pic posted
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Friday, December 12th, 2014 AT 2:22 PM
Tiny
EMMCEEZ
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Sorry for slow reply, had a problem logging in to the site

Here are the pics which I thought I uploaded with my first question.

Regards
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Friday, December 19th, 2014 AT 6:59 PM
Tiny
MHPAUTOS
  • EXPERT
The line drawing is the VSV switch and the idle up valve, the large screw on the end is the fast idle adjuster with the air on (vsv activated) do you have this on your manifold.
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Saturday, December 20th, 2014 AT 3:57 AM
Tiny
EMMCEEZ
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In the first pic (expand the view)you can view the idle up valve and VSV (diaphragm) attached to the manifold.

The second pic is the vacuum sensor for the EFI, mounted on the firewall
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Monday, December 22nd, 2014 AT 9:03 PM
Tiny
MHPAUTOS
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Is the VSV switch activating with the A/C on?
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Tuesday, December 23rd, 2014 AT 9:31 PM
Tiny
EMMCEEZ
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Yes
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Saturday, January 3rd, 2015 AT 2:18 AM
Tiny
MHPAUTOS
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If the VSV is working the idle up valve is faulty or needs adjusting or blocked.
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Saturday, January 3rd, 2015 AT 12:51 PM
Tiny
EMMCEEZ
  • MEMBER
Thanks for that info. Will check and advise.

As an added point, there is whistle coming from the idle up valve, which goes away if I disconnect the inner pipe connection. To the VSV

I need to back up to your last question. And request clarification

How do I verify that the VSV switch is activating, when in motion, as opposed to being at idle. Sorry if this is a dumb question.
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Monday, January 5th, 2015 AT 5:44 PM
Tiny
MHPAUTOS
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The VSV will have vacuum passing through t he valve when activated, this will be when the compressor is on.
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Tuesday, January 6th, 2015 AT 2:14 AM

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