IAC wire connections
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 2,295
Likes: 14
From: Grand Sport #82
IAC wire connections
I am fighting some idle problems on a 87´.
The IAC looks fairly new, but the connector is pretty beaten up, so its hard to determine the orientation of the four pins. Any pictures or schems would be great.
Looking at the sensor female connector, the lockign tab is on top, but what which wire colors goes to which corner?
All pins have voltage with ignition on (0.5V and 12.3V) and with the engine running (voltage changes), but the IAC does not control the idle. (no change from base idle)
The IAC looks fairly new, but the connector is pretty beaten up, so its hard to determine the orientation of the four pins. Any pictures or schems would be great.
Looking at the sensor female connector, the lockign tab is on top, but what which wire colors goes to which corner?
All pins have voltage with ignition on (0.5V and 12.3V) and with the engine running (voltage changes), but the IAC does not control the idle. (no change from base idle)
Safety Car
Joined: Aug 2009
Posts: 3,749
Likes: 275
From: Melbourne, Victoria, Australia
I am fighting some idle problems on a 87´.
The IAC looks fairly new, but the connector is pretty beaten up, so its hard to determine the orientation of the four pins. Any pictures or schems would be great.
Looking at the sensor female connector, the lockign tab is on top, but what which wire colors goes to which corner?
All pins have voltage with ignition on (0.5V and 12.3V) and with the engine running (voltage changes), but the IAC does not control the idle. (no change from base idle)
The IAC looks fairly new, but the connector is pretty beaten up, so its hard to determine the orientation of the four pins. Any pictures or schems would be great.
Looking at the sensor female connector, the lockign tab is on top, but what which wire colors goes to which corner?
All pins have voltage with ignition on (0.5V and 12.3V) and with the engine running (voltage changes), but the IAC does not control the idle. (no change from base idle)
Safety Car
Joined: Aug 2009
Posts: 3,749
Likes: 275
From: Melbourne, Victoria, Australia
Ok had a look at the IAC connector on my 85 for you, looking at the connector with the clip on top and pointing away from you.
To the left of the clip is terminal A to the right of the clip is terminal B
now directly below are the other wires as below looking from the wires to the connector and the clip that secures to the IAC valve up and pointing away. You should be able to see the A and B on the top of the connector where the tab sticks out. The connector cannot be fitted the wrong way.
-"""-
A B
D C
----
Light blue with white stripe goes to A (top left)
Light blue with black stripe goes to B (top right)
Light green with white stripe goes to C (below B)
Light green with white stripe goes to D (below A)
You should be good to go now
Remember the EGR exhaust gas recirculation valve below the plenum that can jam and not seat fully, that will cause a bad idle and stalling at idle. check the IAC was not damaged, they have to be set to 28mm (from tip to where the gasket sits) before fitting into the throttle body.
If the IAC does not change idle it may be bad they tend to seize and do not last forever. You can get a new one quite cheap.
http://www.parts123.com/parts123/yb....5Z50000050F~~~
http://www.ebay.com./itm/SMP-S555-Wi...item2c8215257f
To the left of the clip is terminal A to the right of the clip is terminal B
now directly below are the other wires as below looking from the wires to the connector and the clip that secures to the IAC valve up and pointing away. You should be able to see the A and B on the top of the connector where the tab sticks out. The connector cannot be fitted the wrong way.
-"""-
A B
D C
----
Light blue with white stripe goes to A (top left)
Light blue with black stripe goes to B (top right)
Light green with white stripe goes to C (below B)
Light green with white stripe goes to D (below A)
You should be good to go now
Remember the EGR exhaust gas recirculation valve below the plenum that can jam and not seat fully, that will cause a bad idle and stalling at idle. check the IAC was not damaged, they have to be set to 28mm (from tip to where the gasket sits) before fitting into the throttle body.
If the IAC does not change idle it may be bad they tend to seize and do not last forever. You can get a new one quite cheap.
http://www.parts123.com/parts123/yb....5Z50000050F~~~
http://www.ebay.com./itm/SMP-S555-Wi...item2c8215257f
Last edited by gerardvg; May 20, 2014 at 06:25 AM.
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 2,295
Likes: 14
From: Grand Sport #82
Thanks! That should help alot.
The problem is that the connector on the harness is pretty beat up, with the tabs gone, so it can actually be installed turned 90 or 180 degrees.
I will take a look later tonight, a report back.
I am pretty sure its an IAC problem, as I can get the car to idle fine by opening the throttle valves (increasing base idle). Once warm I can also get the base idle down to 450rpms, but when I hook the IAC back in after the setting procedure, it does not change/increase the idle at all.
The problem is that the connector on the harness is pretty beat up, with the tabs gone, so it can actually be installed turned 90 or 180 degrees.
I will take a look later tonight, a report back.
I am pretty sure its an IAC problem, as I can get the car to idle fine by opening the throttle valves (increasing base idle). Once warm I can also get the base idle down to 450rpms, but when I hook the IAC back in after the setting procedure, it does not change/increase the idle at all.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 763
Thanks! That should help alot.
The problem is that the connector on the harness is pretty beat up, with the tabs gone, so it can actually be installed turned 90 or 180 degrees.
I will take a look later tonight, a report back.
I am pretty sure its an IAC problem, as I can get the car to idle fine by opening the throttle valves (increasing base idle). Once warm I can also get the base idle down to 450rpms, but when I hook the IAC back in after the setting procedure, it does not change/increase the idle at all.
The problem is that the connector on the harness is pretty beat up, with the tabs gone, so it can actually be installed turned 90 or 180 degrees.
I will take a look later tonight, a report back.
I am pretty sure its an IAC problem, as I can get the car to idle fine by opening the throttle valves (increasing base idle). Once warm I can also get the base idle down to 450rpms, but when I hook the IAC back in after the setting procedure, it does not change/increase the idle at all.
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 763
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 763
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Le Mans Master
Joined: Aug 2007
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From: WV
..WW.
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Last edited by WW7; May 20, 2014 at 02:57 PM.
Race Director
Joined: Apr 2002
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From: Anaheim CA
If you look closely at the plastic cylinders that surround the pins you will see that some of them have slots in them. There are corresponding ridges inside the connector part of the IAC and they will prevent you from installing it wrong.
Race Director
Joined: Apr 2002
Posts: 10,036
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From: Anaheim CA
A good way to get part numbers for connectors is to use this site:
http://www.acdelcotechconnect.com/pi/wiring-connectors/
All Corvettes from '84 through '95 use the same connector. The balance switch was eliminated in 1996.