your efi sled and fuel pressure

The current EFI models from Arctic Cat have a specific fuel pressure requirement the engine needs to perform to its potential. Granted, there is a plus-minus scenario thrown in, but the fuel pressure must be within the range for which the engine was calibrated. This range is selected by the type of fuel injector that the engine manufacturer has chosen. This, of course, is done by extensive testing by the engine producer.

The regulator that is used is a simple mechanism made up of a spring and a bellow. The spring rate is pre-determined through testing and then the correct spring is chosen. But over time, like every other spring in the world, the spring can become weak, resulting in low fuel pressure. This is bad!

Low fuel pressure can cause a lazy responding engine or an engine that is flat-out lean, ending in seizure. The other potential problem with an old regulator is the bellow. Over time a bellow can become hard and almost shrink. This may also cause low fuel pressure and potentially result in engine seizure. The material used in a bellow is a high-quality material, but just like everything else in this world (besides rocks), they don't last forever.

If you have a few miles on your EFI and it feels a bit lazy all over, take it to your dealer and have the pressure checked with a GOOD fluid-dampened pressure gauge. If the pressure is not within the range specified by the manufacturer, install a new regulator. It is much cheaper than a new top end.

Special thanks to Tim Berg and his crew at Black Magic Motorsports for this fuel pressure information. For more help, call 218/681-1150.