How to Handle Knock Sensors on LS Engines: Delete, Relocate, or Convert

If you are swapping an LS engine or building one for power, you will eventually face a common question.  What do I do with the knock sensors and are they actually needed? Depending on your setup, you can delete them, relocate them, or convert them to a newer style.

Wire Connector Types

Did you know that there are 2 types of knock sensors found on LS engines?  The Gen 3 engines used the old 350 TBI style, one wire sensors.

These were mounted deep in the valley area that are well known to fill with oil and debris.  When removing the sensors to take the valley cover off, they were known to strip the hex, seize the threads, or just break off entirely.  Next up we have the Gen 4 sensors with 2 pin connectors. 

These were conveniently located on the lower sides of the engine block, above the oil pan flange and attached with a M8-1.25mm bolt.

When You Can Delete Knock Sensors

For many performance builds using standalone ECUs, such as Haltech or Holley Terminator, the knock sensors are often disabled in tuning. The sensors can pick up false readings from valvetrain noise from big lift camshafts, high compression, solid motor mounts, aggressive timing, boost, or a host of other things that the factory knock system was not designed to see.  Most race engines will not have knock sensors on them, meaning that it is up to you to decide what threshold or what reason you give yourself to remove them.  Just know that they are not necessary for your engine to run.

We commonly delete the knock sensors on the Gen 3 engines to give it that clean look.  Especially if we are using a tall intake manifold that really shows off the valley cover. Use ICT Billet part number 551629G, which replaces the factory knock sensor valley cover and makes the top of the engine look much cleaner, while removing the option for the engine to pool water, oil, and debris in the knock sensor holes. 

When these holes fill with water it can short out the wire connection causing false readings that make your engine run poorly.   Gen 4 engines are simple since they are mounted near the oil pan rail and don’t change the engines appearance much, nor require additional parts to remove them.  Just simply unplug them, unbolt them, and say goodbye.

When to Relocate the Knock Sensors

If your sensors are damaged or you’ve decided to move them out of the valley cover area but still want to use them, you’re in luck. For Gen 3 engines, we make these handy relocation adapters 551216-KN30 along with wire extension WEKN030-60. This setup moves the factory sensors from the valley to the side of the block and fits LS1, LM7, LR4, LQ4, LQ9, LS6, L59, LM4, and L33 engines. If a sensor breaks off in the valley, this is the easiest fix.

For Gen 4 engines, use relocation adapter 551216-KN40 and wire extension WEKN040-12. It fits LS2, LS3, LS4, LSA, LY6, L92, L76, L9H, L96, L20, L94, and other Gen 4 blocks. This allows the sensors to be moved to a non-factory location such as moving both the sensors to one side of the engine.  This comes in handy when space is at a premium, whether you have big turbos tying up all the space, 4wd components, or custom brackets, this is the best option for you.  These Gen 4 adapters also work with Gen 5 engines and sensors

Gen 3 to Gen 4 Knock Sensor Conversion

We have run Gen 4 sensors on a Gen 3 block, which is another good option for you to consider, for multiple reasons.  To run the Gen 4 sensors, you will need the wire adapter to convert the single wire sensors to a dual wire sensor WAKN034-36.  The first wire on the Gen 4 sensors will connector to a ground loop then the second wire plugs right to the ECU as the Gen 3 sensor did.  There are a few benefits for switching to the newer sensors.  Such as the having better noise filtering that reduces false knock from valvetrain resonance. They also respond to the ECU faster and they’re less prone to moisture damage thanks to the improved design and mounting location.

Compatible Platforms

All relocation adapters and extension harnesses are made in our Wichita Kansas facility from billet aluminum and USA made wire, OEM tooling, and connectors for maximum reliability, giving you that audible click just like OEM.

ICT Billet – Max Your Swap