Leading/Trailing Coils
 

I recently had my vehicle put back together after a few years of it not running by a reputable shop here locally. They installed a Apexi PowerFC when doing the install. They ran into an issue with a trailing coil that wasn't receiving a signal from the PowerFC. They switched it with the OEM ECU and it sent the signal just fine. They set it up to fire both leading and trailing coils at the same time and this is working. My question to everyone would be is this something that will ultimately ruin my motor and I should replace the PowerFC or is this something that is okay to run. I wasn't 100% sure of why there were leading and trailing coils to begin with. The only idea the shop and I could come up with was for emission testing, which is something I do not need to do. Any help would be appreciative.

Also, it is a stock motor (13B-REW) for a 1993 FD. If you need any other information, I would be glad to provide it.

Thank you.

No shop should have ever set up your trailing to fire at the same time as your leading. Leading fire in waste spark, trailing do not and your timing is way off. I would recommend you stop driving the car right now and buy yourself a PFC that is not fried.

Banzai has it right, firing at the same time can actually blow your motor. Most likely the output transistor for the trailing ignition is blown. I know Rotary Performance in Texas does some PowerFC repairs, they may be able to help you. Or track down another PFC.

Dale

We sent one down to RP a few weeks ago for this, it is not something they can repair. They returned it to us and it is now at Apexi.

Thanks for the help everyone. Last question would be, can i just swap my oem ecu back in to Turn it on? I live in Wisconsin and try to turn it out weekly to get the fluids moving around.

Installing the stock ECU depends on your modifications, and you would need to undo whatever wiring hack was done.

Yep. For general starting and driving as long as you have stock injectors the car will be fine. Depending on mods you may not want to hammer it, but for starting and running the stock ECU will be fine.

Dale

As I understand it, it was due to the shape of the combustion chamber. On the rotary it's long and with a lot more surface area than a piston engine. Two plugs were needed for a complete combustion event. So in a way, it was for emissions.

I’m going to look at seapping in the oem ecu soon just to prevent any possible damage. Does anyone have any suggestions on if my powerFC could get repaired? And if so, where? Thanks again everyone for the input.

Not ideal but you can run just leading plugs and have the engine still run ok, trailing are kind of just for emissions as mentioned above.