Im having a problem with pre ignition.. i installed an Injen CAI kit and ever since then when under hard accleration i get pre ignition. I have tried 94 octane gas, i have tried octane boosters but still the same. I then took off the cold air intake and fitted the orginal intake but with an K&N panel filter but can still hear pre igntion. I have had my car on a dyno with the stock air intake and the CAI, my car runs slightly richer with the CAI and for all those out there thinking about buying an Injen CAI, dont bother.. I lost 10 rwhp in the midrange and 5rwhp at the top end, and about the same numbers in torque. they look good and sound good but thats about it.. has anyone had any problems with pre ignition? the engine is stock apart from the K & N panel filter.

 

Have you checked the MAF sensor or reset the ECU? That might help debug some more. By the way if you have problems running a completely stock setup, just take it to the dealer. Unless you like to drive across the country on weekly basis you should have warranty.

 

i have disconnected the battery for 20 mins but thats about it.. is that how you reset the ECU?

 

yeah disconnecting the battery for that long will reset the ECU

 

Hmmmm..I'm having the same problem with my 2005 g-35 mt, I replaced the air intake with a z tube and wolf's pop charger, still no change. I hear it mostly when shifting from 2nd to 3rd. I took my car to the dear and was told that some pre detonation was normal. Normal?! Are then kidding me...? I still haven't solved this problem...

 

^^
Actually if you check your manual it does state that some detonation/spark knock is normal.

"However, now and then you may notice light spark knock for a short time while accelerating or driving up hills. This is no cause for concern, because you get the greatest fuel benefit when there is light spark knock for a short time under heavy engine load."

Now, this is regarding a light spark knock, and yes, if you roadtest a g35 you will notice a light amount of this occurring. It also says persistent heavy spark knock can possibly cause engine damage, so your best bet is to verify it with your service dept. Don't forget, you also have to account for the modifications on the vehicle, which would also affect the airflow and other parameters which the ecm uses to control such things as the spark advance and timing.

 

OP...Being you have a revup VQ as well it sounds, check for oil consumption. OC will kill oct rating and cause more apparent detonation in lower rpm range under load.

My original VQ did this and my replacement with still some OC as well. Hot days and factory tuned lean AFR's shown in lower rpm with my Dyno pulls on my 06 6mt doesn't help that situation either in general.