87 fc doing the jdm 13bt swap. Pinned out all inputs on the ecu. All read and are within spec. When key is turned I get a quick flash on my spark tester. But nothing after that when cranking. Changed cas and checked connection.. anybody have any idea where to go from here I'm at a dead end

 

Which coil did you test. Make sure the coils are bolted to the fender properly as this is how the item receives a ground. The plugs and or plug wires could also cause this problem.

 

Both. And swapped them out with others. Proper bolting was the first thing i checked

 

The issue could still be the plugs and or wires. You also need a charging system which is not low on voltage as well.

 

Brand new plugs wires and battery

 

Try unplugging the AFM. Try testing for spark in another manner. You can use the spare CAS and plug it into the harness and spin it w/key to on and if you hear some clicking going on then you're getting something. And which ECU did you use.

 

Tryed that as well : / I'm using the ecu that came with the swap. I also bought an n332 still nothing

 

Update:
I've read up that I cannot use the turbo harness that came with the motor. That I need to use the na harness and run the necessary wires for the swap to work. Make any sence?

 

There are different harnesses in the engine bay. Engine, emissions and front harness. I'm not too familiar w/the swap but the JDM engine does not have the multitude of emission equipment that the USDM's do thus the use of the wires in some of the harnesses will be different. And early S4's use low impedance injectors while later S4's do not so that would be an issue which needs to gone over. Also, did you use an S4 or S5 turbo engine?

 

S4 complete swap. Motor tranny harness ecu

 

Have you tried ohming the CAS wires from the CAS to the ECU (unplug the CAS and ohm the plug wires to the ECU w/the ECU plug unplugged-- the wires at the CAS run to the ECU but passes through an intermediate connector before reaching the ECU and a poor mating at this intermediate connector could possibly disrupt the signal )? Is the main engine ground on top of the engine up to speed? And I know we talked about the coil/igniter grounding but sometimes the thread in the fender needs to be cleaned to provide a good ground as grease/dirt buildup is commonplace for that area. Also, the Green/Yellow wire at the lead coil is the trigger signal as it goes from having 0 volts to 5 volts very briefly and then reverts back to 0 volts and goes through this cycle over and over w/key to on. You can only measure this by rotating the engine by hand and rotating the alternator pulley should rotate the main pulley. Lastly, how about taking a reading on the Brown/White wire (Vref) at one of the engine sensors such as the boost sensor or TPS or AFM w/key to on as it should read 5 volts.