Most often this is the result of some sensor being unplugged. Some sensors are unplugged during an exhaust or air cleaner installation and must be re-connected for everything to work correctly. Some things to check: the throttle position sensor located on the side of the throttlebody behind the air cleaner, the intake air temperature sensor also located on the throttlebody behind the air cleaner, both front and rear oxygen sensors located in the exhaust within about 8 inches of the heads, the crank sensor located near the front of the engine close to the front oxygen sensor. If all those sensors are connected, also check the two Fuelpak connectors that they are secure, also check for bent pins, or pins which are not fully seated.

The version 12 software in your fuelpak greatly minimizes this popping. Your software version level can be checked in mode 20. Older versions can be upgraded for a nominal charge by contacting our technical service department.

The version 12 software is able to cut down on this popping by monitoring the throttle position in relation to the engine rpm; if the fuelpak was not calibrated to the throttle position correctly in mode 19, popping or other driveability issues can result. Check the throttle calibration in mode 21 – the numbers should read zero at idle and start increasing smoothly as the throttle is twisted, reading about 50 at half throttle and 99 at full throttle. If the numbers do not appear to be correct, recalibrate the throttle in mode 19.

Some riders do not completely roll off the throttle between shifts or when coasting to a stop. This riding style can lead to exhaust popping. Be sure to fully roll off the throttle.

Exhaust leaks can also cause popping. Check and tighten any leaking exhaust joints.

Lastly, some exhaust systems will pop and there is nothing you can do to completely eliminate it. Systems with large baffles or with open or non-existing baffles are especially prone to popping.

Modern fuel injected engines with high energy ignition systems run a more consistent air fuel ratio and the plugs will look "leaner" than on a carbureted engine. This is normal and is nothing to be alarmed about.

No. The fuelpak settings are created on a dyno by skilled dyno technicians and published in your application chart. As long as you can identify your configuration (year of bike, model, exhaust system, etc.) and find that configuration in the application chart, you will have a dyno-tuned setting. We have thousands of applications and are adding more every day, so it is very likely we will have a dyno-tuned setting for you.

The ECU level refers to the ECM calibration. The factory computer (ECM or ECU) comes from the factory with a pre-installed fuel map (some people refer to this as a "stock burn"). If the dealer installs a pipe on a bike, often they will upgrade the fuel map to "Stage 1". This stage1 setting has nothing to do with a Stage1 air cleaner and should not be confused. If you do not know the ECM calibration level, you can go to the dealer and have them read this information through the diagnostics port.

The Fuelpak settings will stay in memory for over 40 years without a battery connected.

To eliminate exhaust popping on deceleration, the Fuelpak will turn off the fuel going into the cylinders. If this feeling is undesirable, you can raise the number in mode 23.

Version 12 was required for the fuel injected Sportster models. We took this opportunity to add a few new features as well. Version 12 incorporates a strategy to greatly reduce or eliminate exhaust popping. It also allows for upgraded camshafts. If exhaust popping is a problem for you or you are going to change the cam, you should consider upgrading to version 12.

Adding a Fuelpak by itself is unlikely to add any power to your bike. Increasing power requires an increase in airflow and an optimization of the fuel for the new airflow. If you upgrade your exhaust and air cleaner, you will notice your best power increases if you also optimize your fuel delivery for the increased airflow through the engine. The Fuelpak gives you this fuel delivery optimization. Every Fuelpak map is created on a dyno with the exact combination listed; there is no need for you to do any further dyno runs to optimize your fuel delivery.

No, the Fuelpak does not adjust idle speed. Idle speed is controlled by the factory ECM and varies based on many different parameters.