diff --git a/core/src/main/java/org/elasticsearch/common/lucene/search/function/FieldValueFactorFunction.java b/core/src/main/java/org/elasticsearch/common/lucene/search/function/FieldValueFactorFunction.java
index 135cb53f65f..8aa4897a8e0 100644
--- a/core/src/main/java/org/elasticsearch/common/lucene/search/function/FieldValueFactorFunction.java
+++ b/core/src/main/java/org/elasticsearch/common/lucene/search/function/FieldValueFactorFunction.java
@@ -161,9 +161,6 @@ public class FieldValueFactorFunction extends ScoreFunction {
 
         @Override
         public String toString() {
-            if (this == NONE) {
-                return "";
-            }
             return super.toString().toLowerCase(Locale.ROOT);
         }
     }
diff --git a/core/src/test/java/org/elasticsearch/search/functionscore/FunctionScoreFieldValueTests.java b/core/src/test/java/org/elasticsearch/search/functionscore/FunctionScoreFieldValueTests.java
index eef4ed27959..2a780fd9fec 100644
--- a/core/src/test/java/org/elasticsearch/search/functionscore/FunctionScoreFieldValueTests.java
+++ b/core/src/test/java/org/elasticsearch/search/functionscore/FunctionScoreFieldValueTests.java
@@ -69,6 +69,14 @@ public class FunctionScoreFieldValueTests extends ElasticsearchIntegrationTest {
                 .get();
         assertOrderedSearchHits(response, "2", "1");
 
+        // try again, but this time explicitly use the do-nothing modifier
+        response = client().prepareSearch("test")
+                .setExplain(randomBoolean())
+                .setQuery(functionScoreQuery(simpleQueryStringQuery("foo"),
+                        fieldValueFactorFunction("test").modifier(FieldValueFactorFunction.Modifier.NONE)))
+                .get();
+        assertOrderedSearchHits(response, "2", "1");
+
         // document 1 scores higher because 1/5 > 1/17
         response = client().prepareSearch("test")
                 .setExplain(randomBoolean())