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Gaining Horsepower By Pulling the Fuses In A Late Model Camaro

If you are new to owning a 2010 or 2011 Camaro 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. Over time, the ECM will set your Long Term Fuel Trim (LTFT) to the low octane tables.

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 just 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 process is quite simple;

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 diagram 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.

 

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Will these lower octane fuel maps also result in reduced fuel economy?
 

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Is there any thing for the v6?
 

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I'm doing this today. I had my car dyno'ed and Jeff at Heintz Racing suggested that he thought I had bad gas, which was retarding my timing. This in spite my only filling up once since having the car with premium Hess gas, which is what they recommend. Dyno run graph looked choppy with some small peaks and valleys all along the curve, and a dropoff around 5800 rpm.

Since it seems either I got the bad gas at Hess, or maybe just low octane fuel had been used earlier by the previous owner (which seems unlikely given how picky he was!) I decided to try Shell premium this round, topped it off and drove around a few miles, then came back home and popped out the fuses.

Be interesting to see what happens this afternoon on the way to work! : )
 

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I'm more than willing to bet you will notice a remarkable difference, I was amazed when I did the same thing. Trouble is when the vehicle is new and shipped to the dealer, they just put reg gas in it, most do not have a "high test" tank of fuel. All it takes is one low octaine dose to set the fuel tables back and they stay there forever unless you do a fuse pull.

Congrats! Let us know how it turns out!:thumbsup:
 

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Well I didn't get on it too hard on the way to work but I have noticed smoother idle and better response off idle, and much less popping on deceleration while downshifting, something I only noticed after putting on my Flowmaster axle backs. More driving tomorrow, and may run by Heintz to see about hooking up a laptop to it.
 

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You have a tune where the LTFT's are already modified and adjusted to levels probably higher to the factory high trims so I wouldn't expect to see anything on a tuned car already.
 

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Nope, just do the fuse pull and give it an hour or two that's all.;)
 

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Provided it had low octane fuel in it at one time, and now has super in it, the difference is quite dramatic.
 

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pulling fuses today, I had some bad gas and have run 5 tanks through with still a small hesitation at low RPM, more noticeable when warming up, kinda studders a little during the accelration.
 
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