The Subaru SVX World Network   SVX Network Forums
Live Chat!
SVX or Subaru Links
Old Lockers
Photo Post
How-To Documents
Message Archive
SVX Shop Search
IRC users:

Go Back   The Subaru SVX World Network > SVX Main Forums > Technical Q & A

Reply
 
Thread Tools Display Modes
  #31  
Old 11-14-2007, 07:24 PM
Trevor's Avatar
Trevor Trevor is offline
Registered User
 
Join Date: Feb 2002
Location: Auckland, New Zealand
Posts: 5,223
Registered SVX
By-Pass Air Control Solenoid Valve
Cleaning, setting and Testing.

Description.

The By-Pass Air Control Solenoid Valve, or Idle Air Control Valve, allows the Engine Control Unit/Computer, to adjust the inlet of air after the throttles, in order to control idle speed. One obvious function is to increase the airflow when the air conditioning system imposes an extra load on the engine.

The unit comprises a rotary solenoid valve, biased towards a central rest position, by means of a permanent magnet. A double wound coil provides reversing open closed operation from a mean rest position, at which point the valve is half open. This arrangement provides two way variable control, dependent on the applied voltage.

Three electrical connections are involved. The centre pin on the connector is common to both windings and is energised positive. The remaining two connections provide for open and close operation of the valve.

Cleaning and Adjusting.

Cleaning is best achieved by removing the solenoid coil by undoing the two attachment screws, which pass through slotted holes so as to provide a degree of adjustment. Make a scratch mark so that the original position can be retained after reassembly. Magnetic force will be apparent as the solenoid coil is separated from main body.

The armature which rotates in ball races, when moved by hand should rotate open closed, with virtually no resistance. The valve should be cleaned of foreign matter using a suitable solvent/lubricant so that it is completely free to move.

After reassembly the valve should rest in a position, half open and half shut when set to the original mark. If there is a large discrepancy, this may indicate that the setting has been tampered with at some time and it should be reset.

Testing.

The solenoid resistance should measure 9 ohms, each side of the common connection, i.e. 18 ohms overall, a small tolerance being acceptable.

With positive to the common connection, 8 volts DC applied separately in turn to the two remaining connections, should fully open and close the valve from rest. Return to the rest position should occur, reliably without hesitation. In the event that 12 volts must be used, this will suffice for intermittent testing, but the extra torque available must be appreciated,

If a variable voltage source is available, continuous opening closing according to the applied voltage can be reproduced. However this test is in no way a necessity.
__________________
Trevor, New Zealand.

As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit!
Reply With Quote
  #32  
Old 11-14-2007, 09:42 PM
jeffast jeffast is offline
I kill more trannies then god
 
Join Date: Apr 2006
Location: wyotech
Posts: 1,209
fixed, no more high idle, idles at 2k till it warms up then drops down to 900, no problems what so ever
__________________
1991 xt6 eg33?
1993 gc track car
Reply With Quote
  #33  
Old 11-14-2007, 10:19 PM
Trevor's Avatar
Trevor Trevor is offline
Registered User
 
Join Date: Feb 2002
Location: Auckland, New Zealand
Posts: 5,223
Registered SVX
Quote:
Originally Posted by jeffast View Post
fixed, no more high idle, idles at 2k till it warms up then drops down to 900, no problems what so ever
All is not as it should be. Normal warm idle should be 610 +- 100 RPM as per specs and idle speed should not exceed 1,500 RPM at any time. A car with manual transmission should be no different. I would rate a a quick drop in revs at shut throttle, as being very important, and this calls for a low idle speed.

My car normally idles at no more than 600 RPM. During a very short warm up at 1,100 RPM or less, and then never at more than 650 RPM, regardless of parasitic loads.

P.S. My last detailed post was intended for Guyver280z. I trust that he does not miss it.
__________________
Trevor, New Zealand.

As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit!

Last edited by Trevor; 11-15-2007 at 02:27 AM.
Reply With Quote
  #34  
Old 11-15-2007, 08:14 AM
Guyver280z's Avatar
Guyver280z Guyver280z is offline
Registered User
 
Join Date: Apr 2007
Location: Tempe, AZ
Posts: 232
Send a message via MSN to Guyver280z
Great!!! Thanks Trevor... that was clear and seems to be easy to do, so i'll try that this weekend.

I noticed while my car was idling at 2,000 when I turned on the A/C the idle went down to 1500/1300 and slowly settle down to 1100/1000.... i think im going to need to replace my valve anyways... but first ill try to test it like you said

THanks.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 10:34 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
© 2001-2015 SVX World Network
(208)-906-1122