If it turns over and starts to fire up sometimes, it seems like you're getting spark. But start there anyways. Pull the wires off your coils and crank the car over. If you see spark in the coils, you've got spark. If you don't have any spark, you'll have to check possible reasons why such as the ECU, Power Transistor Unit, Coils, etc.
Next thing I'd check is to make sure your MAF connector is plugged in. If you did any monkeying around in the engine bay, you might have knocked it off. It's the connector right next to the intake on the black piece (MAF).
That being fine, check fuel. Do you have gas in the car? Seriously... hehe. Next, make sure your AFCII is still plugged in and running and that the LO settings are still in the same range as they were before. I'd suggest you post them here for us to see (I believe you're running 550s so you should GENERALLY be in the -25 to -32 range at idle RPM). If you don't yet understand the AFCII, you can find instructions for it on
http://www.apexi-usa.com/productdocumen ... 2Final.pdf.
If your AFCII seems fine... You can check voltage at the fuel pump. Hook a voltmeter up to the 12v power of the fuel pump in the access panel of your trunk (its very easy to get to). When cranking you should see 12V at the pump. If you dont have 12V, the pump isnt pumping and there's your problem. Likely the MFI relay, fuel pump relay, or ECU then (you can test these from procedures in the service manual). If you DO see 12V when cranking, then you gotta check fuel pressure along the way. Disconnect the return fuel line from the Fuel Pressure Regulator off the rear fuel rail. Hook up another hose to that line and feed it into a gallon of milk. Crank the car, you should get tons of fuel pouring into your milk container when cranking. If you dont, you have a problem with fuel getting from your fuel pump to injectors. Possible a bad fuel filter...
Seriously though. Figuring out problems as to why the car won't start aren't terribly difficult, you'll get it going! it's just a little time consuming...
Also, prior to checking ALL the above, double-check ANYTHING you might have possibly changed/worked on SINCE it last ran.
Jesse
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Best in Show - NG07
2010 - 6G74/3.5L E16Gs - 688awhp/679awtq (Race+Meth)
2011 - 6G74/3.5L 68HTAs - 740awhp/762awtq (Race+Meth)
2013 - 6G74/3.5L MTC Stage4 - 908awhp/832awtq (Race+Meth)
