Help No Spark on Fourth cylinder!!!

[E10]

No spark from 4th cylinder, its not the coil pack i can swap it to the 3rd and it fires just fine. I have a new wire harness from wiring specialties so know its not wiring. Since I am getting spark in 3 of them I dont think its the CAS/Distributor. I'm leaning towards a bad ECU and my girlfriends dad is leaning towards bad ignitor chip but all a ignitor chip does is amps voltage (at least i think thats what it does.)

If it is a bad ECU where can i find a 62 or E5 Ecu for a good price? I have a black top S13

Mike

[codyace]

Do you have an FSM to troubleshoot it? http://www.nicoclub.com/FSM and then select the one you need.

I'd still start with FSM diagnosis and Ignitor diagnosis first. While it may amplify the power to them, it is still the trigger for the pack. Each coilpack will havve 12v power, Ground, and then the trigger off the ecu through the Ignitor. They are pretty simple so good luck with the troubleshooting.

FWIW: ECU's usually have injector drivers fail, but not coilpack signal resistors...

[E10]

I tested the ignitor before i put it in my new wire harness i bought from wiring specialties. I used the fsm to test it and according to the fsm it passed.

The first time i went to start the engine when i got it i rewired my harness and connected a positive to a ground wire. Thats why i bought a new harness.

I checked pin #9 if i remember correctly but its the ground signal to coil 4. I compared it to the others and it wasn't sending out any ground signal. I had a pinout when i did it so if its not the right pin its because im going by memory.

I'm really leaning towards a fried ecu