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A/C works with standalone ECU, doesn't work with stock ECU?


turbofonz
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Galant VR-4 org Post #: 1237766 posted 06/05/17 07:50 PM     Remind Me!  Send Private Message   Edit Post      
Is this making sense? Swapping my car from an AEM to ECMlink makes my a/c stop working. Is this pinpointing any specific sensor I should be looking for?

I added this to newbies, because this sounds ridiculous.



Ryan W.
91 TSi AWD - 9 sec stock bottom end and corn fed
91 Galant VR-4 - Summit White - 153/2000
91 Galant VR-4 - Summit White - 490/2000
91 Galant VR-4 - Nile Black - 369/2000
92 Galant VR-4 - Summit White - 255/1000 - [email protected] - sold

Posts: 427 | From: Granby, MA | Member Since: 09/27/06 | IP: (73.149.65.160) | Report this post to a Moderator

thomcasey
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Galant VR-4 org Post #: 1237770 posted 06/06/17 06:02 AM     Remind Me!  Send Private Message   Edit Post      
Pin 65 on the ECU plug(s), A/C Clutch Relay Output seems like a likely candidate



Thom
1991 GVR-4 1025/2000 (PTE 1200's, 16g, DSMLink v3, gm-maf, eagle/ross, .020 over, 272's)

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turbofonz
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Galant VR-4 org Post #: 1237970 posted 06/13/17 10:29 PM     Remind Me!  Send Private Message   Edit Post      
Grounding pin 65 makes the compressor kick on. It's looking like it may be an issue with the dual pressure switch or a/c coolant switch?



Ryan W.
91 TSi AWD - 9 sec stock bottom end and corn fed
91 Galant VR-4 - Summit White - 153/2000
91 Galant VR-4 - Summit White - 490/2000
91 Galant VR-4 - Nile Black - 369/2000
92 Galant VR-4 - Summit White - 255/1000 - [email protected] - sold

Posts: 427 | From: Granby, MA | Member Since: 09/27/06 | IP: (73.149.65.160) | Report this post to a Moderator

FlyingEagle
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Galant VR-4 org Post #: 1238083 posted 06/17/17 11:06 PM     Remind Me!  Send Private Message   Edit Post      
What function did the AEM have over control of the AC system?

Usually it is simply a trigger for the AC compressor clutch relay, and it could be held back by the factory HI/LOW pressure switch and AC temp sensor.

If it worked before, check to make sure the function coming out of the ECU is correct - IE is there power at the wire leading up to the connector for the AC clutch.

If you manually trigger the clutch (engine off), is the AC pulley magnetized (following confirmation that you have power headed down to the AC clutch connector and assuming a good ground)?

Confirm what pressure you have in the AC system if possible.

A few possible scenarios for you. I think this will be something simple if both ECU's control the same functions .... like a wire is not hooked up properly, etc.



C53A 1 of the ~1500

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turbofonz
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Galant VR-4 org Post #: 1238133 posted 06/22/17 07:19 PM     Remind Me!  Send Private Message   Edit Post      
I really don't know anything about AEM, after doing a head change and the car running like crap, I put ECMlink in because I know it well.

The FSM doesn't give much info for testing the dual pressure switch or the temp sensor, other than checking continuity which they both have. So that is leaving me kind of lost.



Ryan W.
91 TSi AWD - 9 sec stock bottom end and corn fed
91 Galant VR-4 - Summit White - 153/2000
91 Galant VR-4 - Summit White - 490/2000
91 Galant VR-4 - Nile Black - 369/2000
92 Galant VR-4 - Summit White - 255/1000 - [email protected] - sold

Posts: 427 | From: Granby, MA | Member Since: 09/27/06 | IP: (73.149.65.160) | Report this post to a Moderator

turbofonz
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Galant VR-4 org Post #: 1238243 posted 06/28/17 10:07 PM     Remind Me!  Send Private Message   Edit Post      
Alright, after spending some time and actually looking it over, using this:

The GR wire from dual pressure switch to a/c engine temp sensor doesn't have continuity which seems to be the issue. dual pressure switch has voltage in and out..

So the question is, does anyone know where that wire runs on the car? From the dual pressure switch to the a/c temp switch on the tstat housing



Ryan W.
91 TSi AWD - 9 sec stock bottom end and corn fed
91 Galant VR-4 - Summit White - 153/2000
91 Galant VR-4 - Summit White - 490/2000
91 Galant VR-4 - Nile Black - 369/2000
92 Galant VR-4 - Summit White - 255/1000 - [email protected] - sold

Posts: 427 | From: Granby, MA | Member Since: 09/27/06 | IP: (73.149.65.160) | Report this post to a Moderator

KiNgMaRtY
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Galant VR-4 org Post #: 1238268 posted 06/30/17 01:08 PM     Remind Me!  Send Private Message   Edit Post      
Do you have a better/bigger picture of the above image? Where is the Dual Pressure switch actually located?
I am also trying to figure out my very similar issue. My car had an Apexi SAFC, perfectly working AC, I replaced it with ECMlink and a new intake pipe and my AC stopped working immediately after the install. I am now interested in trying to figure out what went wrong.



92 GVR4 #802 link
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turbofonz
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Galant VR-4 org Post #: 1238273 posted 06/30/17 05:21 PM     Remind Me!  Send Private Message   Edit Post      
That pic was linked in some other a/c thread on this site. just save as and zoom in.

Dual pressure switch is under the stock coolant overflow reservoir. 2 wire plug, green/red and green/yellow wires going to it. That gets power from the A/C button, and runs to the 2 wire sensor on the thermostat housing, then goes to the ecu it looks like. somewhere between those 2 i'm losing connection



Ryan W.
91 TSi AWD - 9 sec stock bottom end and corn fed
91 Galant VR-4 - Summit White - 153/2000
91 Galant VR-4 - Summit White - 490/2000
91 Galant VR-4 - Nile Black - 369/2000
92 Galant VR-4 - Summit White - 255/1000 - [email protected] - sold

Posts: 427 | From: Granby, MA | Member Since: 09/27/06 | IP: (73.149.65.160) | Report this post to a Moderator

FlyingEagle
Doesn't Match Anything


Galant VR-4 org Post #: 1238278 posted 06/30/17 08:17 PM     Remind Me!  Send Private Message   Edit Post      
If you paperclip the require connection at the inbound and outbound connections for the dual pressure switch, you can control the relay for the compressor clutch and confirm the control wiring, and clutch function with this manual test.

Be sure to remove the connector and only use the required pins. File down the ends of the paperclip so as to not enlarge or over stress the pin contacts in the connector you are working with. The paperclip has to mimic the exact thickness of the pins in the switch assembly.

This will either confirm the switch being bad (out of calibration/dead) or switch being good and system pressures actually being out of spec.

Also, the AC engine coolant switch is inline and a second fail safe shutoff device to maintain engine operation but defeat AC if things get too hot. Confirm this switch is good also, or even hooked up for that matter. Maybe something got bumped.



C53A 1 of the ~1500


Edited by FlyingEagle (06/30/17 08:20 PM)

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turbofonz
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Galant VR-4 org Post #: 1238736 posted 07/25/17 06:43 PM     Remind Me!  Send Private Message   Edit Post      
I guess I should update with what the fix was. The green/red wire I spoke of before has a splice near the fusebox inside the wire loom that runs parallel to the firewall. One of the wires was at the splice was barely making connection. Fixed that, and a/c works as it should. Must of been a coincidental issue while doing the head swap.



Ryan W.
91 TSi AWD - 9 sec stock bottom end and corn fed
91 Galant VR-4 - Summit White - 153/2000
91 Galant VR-4 - Summit White - 490/2000
91 Galant VR-4 - Nile Black - 369/2000
92 Galant VR-4 - Summit White - 255/1000 - [email protected] - sold

Posts: 427 | From: Granby, MA | Member Since: 09/27/06 | IP: (73.149.65.160) | Report this post to a Moderator

FlyingEagle
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Galant VR-4 org Post #: 1238740 posted 07/26/17 11:24 AM     Remind Me!  Send Private Message   Edit Post   
Hurray for the simple fix ... !!!



C53A 1 of the ~1500


Edited by FlyingEagle (07/26/17 11:25 AM)

Posts: 1517 | From: THE Ottawa | Member Since: 03/05/05 | IP: (108.63.97.28) | Report this post to a Moderator


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