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Hi guys, I am running the aem with LS1 coils and the EPM. After doing the conversion the car runs great and has been to the track many times with good results. However every once in a while when I turn the ignition on before starting the car I get a backfire, one time bad enough to bend my throttle body butterfly. After looking into this I found coils 2 and 8 ignite every time I turn the ignition on. The coils are wired from following the epm intall thread on here and like I said the car runs fine, just this one issue. The fact that only cylinders 2 and 8 fire even after turning the engine to different positions tells me the ECU is somehow sending a singal briefly activating only these coils. Could there be a setting in my tune that could cause this. Any ideas ?
Thanks
 

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Small update. Did some more testing today and traced the ground wires to double check my wiring. I ended up disconnecting the ECU gnd (brown wire) from all coils with the same result. I also jumped the ECU relay which eliminates that. The only way I can get the coils to not spark is to remove the fuse that powers them, turn the ignition on, then insert the fuse. So by running a seperate switch to the coils and turning it on after the ignition is turned on would eliminate this issue but is still not right (That will be my last resort). My next step would be to compare the signal wires from the ecu with the sparking coil vs the others and compare. Why the ECU would be sending a brief signal to just coils 2 and 8 is a mystery to me. Others have suggested upgrading my firmware to the newest version as I'm still running V1.11. But thats the only suggestions I have had so far.
 

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To anyone with experience in this problem, my install does the exact same thing. Sometime when I put the KOEO (start position, motor not running) it will backfire air throughout the intake. It only does this after the car has been started and ran, never on a fresh cold start. I am wondering if it's a wiring issue or something in the program. My box is a 30-1400 with the latest updates (aem went thru it a year ago) and I am running ver. 1.21 for the cal. I have been reading as many COP install and wiring notes as I could find but don't see anything glaring.

I am running LQ9 coils. I am running the the A pin (black) to ground (grounded to bus bar connected to battery) and am not running anything at B pin (brown)(which is supposedly the the ECU ground). Do I need to run something to B pin? If so ground it to where?

There has to have been others with this problem or installers/tuners with this issue. Please let us/me know where to look. The car runs good otherwise. Thank you.
 

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We'll, no updates yet. Please someone help me with this. There has to be others who have ran into the same problem. It is the coils firing when you turn the key to the on position but not crank the car over. There is a brief backfire since there is still fuel in the air. AEM forums are still down and on last look there was no answer to this.

I have since redid the grounds using both the black ground to chassis and the brown ground back to ECM ground, no change, same problem. Please help a fellow AEM cop user out and tell me where to look. Thank you.
 

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