So installed a new fmic after removing my old one and my car won't start. I have fuel pressure so I checked spark and I have none. I checked all my connectors I touched. knock sensor, maf sensor, lights, p/s pump, alternator and crank angle sensor. all are ok. checked all my fuses, had one that was blown but not related to any engine components. checked both ignition coils and crank angle sensor, all of those check out. I have ignition power going to both coils. checked the condenser and ground after the coils, both are ok. checked wiring from pcm to both coils and to the crank angle sensor, wiring is all good. I even tried a good working crank angle sensor to be sure. This car ran fine before I put this in... The only thing i can think of i was in the process of moving my alt out of the way and sparked a bit on the 2 pin connector on the back. I then immediatley removed the battery. I thought I might have blown a fuse for it but I have power on both of those pins. The only thing I can think is that my pcm somehow fried itself or there is a ground somewhere that I disturbed. Can anyone else think of something else thats causing no spark? I'm in the process of getting a tester pcm but until then I'm stumped.. any ideas???

 

Sounds like you may have deep fried the ECU with the sparky surge. Next time, follow the good mechanic's first step when working on anything on the car:

Disconnect battery.


You did say that you checked the coils... you do know that they have the ignitors built into them, right? The signal path is from the CAS to the ECU to the ignitors to the coils. The primary and secondary sides of the coils may check out with an ohmmeter, but if the ignitors are bad, it won't spark. Unfortunately, the only 2 things that are common to the whole equation would be the CAS and ECU (*If you have no spark on ANY coil). The trailing coils each have their own ignitors I think.

 

Here is an idea for you. Is your primary coil grounded good? You probably had to change the mounting point for it unless you have a single side piped intercooler like the HKS or RE. If it isn't grounded you won't be able to start your car.

 

describe what it's doing. It cranks over really fast and won't start? It won't even crank over? It cranks over and sputters but never starts?

 

thx everyone, about 45 mins after I posted it I found that my pcm had no ground... I had checked all of my ground locations and they were good but i must have pinched or cut off a wire somewhere... I couldn't find it so I ran a new ground. Started right up and sounds great. thx again!

 

RX-7s don't have a "PCM". The ECU controls only the engine, not the whole powertrain.

The ECU should ground to the top of the engine via the emissions harness. Check carefully around that area to make sure nothing else on the harness has been damaged.