Why would anyone want to have a perfectly good working ECM re flashed? Here's one reason out of many that you might want to consider.

You've purchased and installed some "high performance" parts for your vehicle and they look great under the hood. The problem is that your not getting the increase in performance that you were told you would. Something still doesn't "feel right" with the newly installed parts. The problem may lie in your ECM.

Two decades ago a screwdriver and a 9/16 inch wrench was about all you needed to get an increase in performance in your vehicle. By advancing the vehicles timing a few degrees, removing the air cleaner filter and adjusting the carburetor you were able to gain a NOTICABLE improvement in performance. If you were real knowledgeable and had a Chevy with an automatic, you could make it shift quicker and firmer by removing the modulator valve spring in the transmission. This also caused the vehicle to shift at higher RPM's. More on this later. Now on to today's engines and transmissions.

Today's engines and transmissions rely on electronics to adjust everything from fuel mixture to when and under what conditions your automatic transmission shifts. By monitoring air intake, exhaust, camshaft and crankshaft position, RPM's and a host of other sensory inputs, the vehicle's computer ( ECM) determines multiple vehicular adjustments on a moment to moment basis. This ever changing constant data stream is what makes your vehicle run correctly. When you change or modify an engine part, including external bolt-on parts, you have changed the parameters that the engine performs under.

For example, if you modify your induction system from stock by bolting on a cold air system, you have changed the volume of air that the engine is capable of ingesting. Since the engine can "breathe" better it now is capable of producing more horsepower assuming it can get the proper fuel and timing increase. Your ECU is still working with the factory settings so it does not have the ability to richen up the fuel mixture or advance the timing to optimum performance settings. Given these conditions, changing the settings in your ECM by re flashing can noticeably increase the performance of your vehicle.

So now your ECM is re flashed and you can feel the increase in performance but your transmission is shifting at 5600 RPM. Your engine is capable of 8000 plus RPM's but your automatic transmission is shifting at 5600 RPM just as you get into your engine's torque curve. Now what?

NEXT - TCM REFLASHING MODIFYING TRANSMISSION SHIFT POINTS