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JEREMY74
Joined: 19 Oct 2012 Posts: 20 Location: Illinois
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Posted: Fri Aug 02, 2013 8:47 am Post subject: ac question |
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when i run my ac it feels like the power lags down a little when the ac clutch goes on and comes back up when the clutch turns off. does this mean my compressor is going bad? thanks for the help. _________________ 1987 PORSCHE 924S |
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Rasta Monsta

Joined: 12 Jul 2006 Posts: 11733 Location: PacNW
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Posted: Fri Aug 02, 2013 9:35 am Post subject: |
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It means you have a 25 year old German ac compressor that was inefficient at best when it was brand new. If cold air comes out, consider that a miracle. _________________ Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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JEREMY74
Joined: 19 Oct 2012 Posts: 20 Location: Illinois
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Posted: Fri Aug 02, 2013 9:58 am Post subject: |
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yes nice and cold. just didnt have the lag to it before. _________________ 1987 PORSCHE 924S |
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JEREMY74
Joined: 19 Oct 2012 Posts: 20 Location: Illinois
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Posted: Sat Sep 07, 2013 11:42 am Post subject: |
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i was wondering if my compressor is seizing up or lagging the belt will that hurt the engine? _________________ 1987 PORSCHE 924S |
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JEREMY74
Joined: 19 Oct 2012 Posts: 20 Location: Illinois
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Posted: Sat Sep 07, 2013 11:43 am Post subject: |
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i was wondering if my compressor is seizing up or lagging the belt will that hurt the engine? _________________ 1987 PORSCHE 924S |
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edredas

Joined: 09 Dec 2004 Posts: 861 Location: Charlotte, NC
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Posted: Sat Sep 07, 2013 6:32 pm Post subject: |
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The compressor puts quite a load on the engine. The DME knows when the A/C is turned on and uses the Idle Stabilizer Valve (ISV) to compensate for this load by increasing the idle speed. However, this can't happen if the Idle switch on the throttle body is out of adjustment or the ISV is no longer working... so be sure to check them. _________________ '84 944 -White, Brown interior
'84 944 -Red, Automatic
'86 944 -Garnet, Fully loaded, Koni suspension
'87 924S -Red, 300hp 951 swap
'87 924S -Red, Project Car
'88 924S -Red, Daily Driver |
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JEREMY74
Joined: 19 Oct 2012 Posts: 20 Location: Illinois
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Posted: Sun Sep 15, 2013 10:08 am Post subject: |
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can you tell me how to check that its working ok? i am pretty handy if i have some place to start at. _________________ 1987 PORSCHE 924S |
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JEREMY74
Joined: 19 Oct 2012 Posts: 20 Location: Illinois
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Posted: Sun Sep 15, 2013 10:08 am Post subject: |
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can you tell me how to check that its working ok? i am pretty handy if i have some place to start at. _________________ 1987 PORSCHE 924S |
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edredas

Joined: 09 Dec 2004 Posts: 861 Location: Charlotte, NC
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Posted: Mon Sep 16, 2013 5:13 pm Post subject: |
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Here's a link showing how to test the throttle position switch. Before you start troubleshooting, verify that the switch is adjusted properly by rocking the throttle cam back and forth with your ear next to it. If you hear a faint click, it is correct, but could still be faulty.
http://www.clarks-garage.com/pdf-manual/ign-03.pdf
If the throttle switch is working properly, then it could be the ISV. I'm not aware of any way to troubleshoot it short of removing it and verifying its operation. However, I do like to touch it and see if it is vibrating when the key is in the ACC position before going that far. That will atleast give you an indication if there's a wiring problem. _________________ '84 944 -White, Brown interior
'84 944 -Red, Automatic
'86 944 -Garnet, Fully loaded, Koni suspension
'87 924S -Red, 300hp 951 swap
'87 924S -Red, Project Car
'88 924S -Red, Daily Driver |
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JEREMY74
Joined: 19 Oct 2012 Posts: 20 Location: Illinois
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Posted: Tue Sep 24, 2013 8:46 am Post subject: |
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thanks for the help ill try to work on as soon as i can find some time. thank you for the link.much appreciated. _________________ 1987 PORSCHE 924S |
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JEREMY74
Joined: 19 Oct 2012 Posts: 20 Location: Illinois
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Posted: Tue Sep 24, 2013 8:46 am Post subject: |
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thanks for the help ill try to work on as soon as i can find some time. thank you for the link.much appreciated. _________________ 1987 PORSCHE 924S |
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