If you are new to owning a 2010+ Camaro SS equipped with the L99 or LS3 V8 engine, then you may not be aware of a simple trick that could unleash a few extra horsepower.
There are two specific spark timing tables housed in the memory of the vehicle’s Electronic Control Module (ECM). One is used for cars running high octane fuel and the other for when the vehicle is using low octane fuels. Whenever you drive the vehicle, the ECM is constantly making decisions based on the data it receives from all of the sensors in the engine and exhaust.
The problem:
It seems that if someone puts a low octane fuel into the tank, the vehicle can’t recover from the low octane table. Once in the low octane table the car will continue to use that information even if you are now using a higher octane fuel. Of course the side effect of this is sluggish performance, and we don’t really need to explain the benefits of running a higher octane fuel in a performance application. If you recently purchased your Camaro you wouldn’t be incorrect in thinking that it isn’t uncommon that at some point the car was filled with a less potent gasoline, especially if it came from a used car dealership or from an owner who was uninformed of this problem and wanted to save a few bucks at the pump. The LTFT’s are, unfortunately, a part of the car’s non-volatile memory. That means the information is stored there, and doesn’t reset when the vehicle is turned off.
However, there is a way around this problem. Although the spark tables are part of the non-volatile memory and cannot be removed, they can be reset. A simple solution is to remove a couple of fuses from the fuse block in the engine compartment. Pulling the fuses will allow your Camaro’s ECM to reset itself to the high octane table. If you are running high octane fuel then it remain in the high table until the ECM again detects a low octane fuel.
The fix:
First, make sure the car is empty of the low octane fuel. Run the tank down low and refuel with high octane. You might consider running a tank or two through before attempting the fuse pull. Once you have better gasoline in the system, locate the two fuses shown in the diagram below. They are in the fuse box located on the passenger side of the vehicle’s engine bay. The fuses are in position #5 and #20. Remove each of these 15 amp fuses and allow the car to sit for a period of at least a few hours. There is a small, grey fuse pulling tool located on the fuse panel (In the image below it would be in the lower right corner area). That should make the pulling of the fuses easier. If possible, remove the fuses and allow the car to sit overnight. Once they have been out for several hours, replace the fuses. When started, the car will attempt to use the high octane fuel trims first, and if you keep high octane fuel in the car it should remain on the higher table permanently. Of course, lowered octane fuel in the tank means repeating the process.
