diff --git a/parsecsv.lib.php b/parsecsv.lib.php
index 7b1ff8a..4c5b7cc 100644
--- a/parsecsv.lib.php
+++ b/parsecsv.lib.php
@@ -905,8 +905,8 @@ class parseCSV {
     /**
      * Validate a row against a single condition
      *
-     * @param array  $row         array with values from a row
-     * @param string $condition   specified condition that the row must match
+     * @param array  $row       array with values from a row
+     * @param string $condition specified condition that the row must match
      *
      * @return string single 0 or 1
      */
@@ -1181,7 +1181,12 @@ class parseCSV {
         $enclosed = false;
         $current_row = 1;
         $to_end = true;
-        $pattern = '/[' . preg_quote($this->auto_non_chars, '/') . ']/i';
+
+        // The dash is the only character we don't want quoted, as it would
+        // prevent character ranges within $auto_non_chars:
+        $quoted_auto_non_chars = preg_quote($this->auto_non_chars, '/');
+        $quoted_auto_non_chars = str_replace('\-', '-', $quoted_auto_non_chars);
+        $pattern = '/[' . $quoted_auto_non_chars . ']/i';
 
         // walk specific depth finding possible delimiter characters
         for ($i = 0; $i < $strlen; $i++) {
diff --git a/tests/methods/ParseTest.php b/tests/methods/ParseTest.php
index 37fe8f0..f05781a 100644
--- a/tests/methods/ParseTest.php
+++ b/tests/methods/ParseTest.php
@@ -52,6 +52,16 @@ class ParseTest extends PHPUnit\Framework\TestCase {
         $this->assertEquals($expected_data, $row);
     }
 
+    public function testAllNumericalCsv() {
+        $this->csv->heading = false;
+        $sInput = "86545235689\r\n34365587654\r\n13469874576";
+        $this->assertEquals(false, $this->csv->auto($sInput));
+        $this->assertEquals(null, $this->csv->delimiter);
+        $expected_data = explode("\r\n", $sInput);
+        $actual_data = array_map('reset', $this->csv->data);
+        $this->assertEquals($expected_data, $actual_data);
+    }
+
     public function test_sep_row_auto_detection_UTF8() {
         $this->_autoparse_magazine_file(
             __DIR__ . '/../example_files/UTF-8_with_BOM_and_sep_row.csv');