diff --git a/FAQ/knock_sensing.md b/FAQ/knock_sensing.md
index 65e26e3..d1fe32a 100644
--- a/FAQ/knock_sensing.md
+++ b/FAQ/knock_sensing.md
@@ -16,5 +16,5 @@ TODO MattK
 
 We also have some results with ion sensing but it's not ready for end users
 
-
+[rusEif ion sensing](https://github.com/rusefi/rusefi_documentation/blob/master/misc/Saab_Trionic_8_Combustion%20Detection%20Module_on_Mazda_Miata_running_rusEfi/Saab_Trionic_8_Combustion%20Detection%20Module_on_Mazda_Miata_running_rusEfi.md)
  
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