I recently upgraded to the intel d945gclf2 from a via ms12000. Everything worked correctly prior to the upgrade, and other than this problem the carputer has been working fine for the past couple weeks.
The only wiring I changed was adding a 4pin molex -> p4 4pin connector for the new motherboard. What worries me is that the first time bench-testing, the computer would start up, shut down, and start up again. I think I accidentally reversed the J8 and J5 (LED) plugs on the m2atx, so J5 may have been connected to the motherboard's power switch header.
The problem: my computer will only suspend correctly when I turn off my car and the m2atx triggers the suspend.
When I try to suspend via windows (start->suspend) or via a separate momentary power button (wired in parallel to the J8 header), the carputer turns off quicker than normal and will not come back from suspend when the power button is pressed again. The fans and screen come on, but nothing shows up on the screen nor does music resume. I have to remove and reconnect the power to the carputer to get it to start normally again.
I found a thread talking about how the J8 header has polarity, so I tried every combination of plugs I could, but that didn't change anything. I also tried starting the computer, unplugging the J8 header, and then pressing the momentary power to suspend the carputer, but that didn't change anything either.
I don't really know where to go now. It seems to me it's a problem with the m2atx supplying power to the board during suspend that's not working unless the m2atx initiates the suspend.