diff --git a/libraries/AP_EFI/AP_EFI_Serial_MS.cpp b/libraries/AP_EFI/AP_EFI_Serial_MS.cpp
index 29a6000377..78fb2e55a3 100644
--- a/libraries/AP_EFI/AP_EFI_Serial_MS.cpp
+++ b/libraries/AP_EFI/AP_EFI_Serial_MS.cpp
@@ -43,12 +43,15 @@ void AP_EFI_Serial_MS::update()
 
     const uint32_t expected_bytes = 2 + (RT_LAST_OFFSET - RT_FIRST_OFFSET) + 4;
     if (port->available() >= expected_bytes && read_incoming_realtime_data()) {
-        last_response_ms = now;
         copy_to_frontend();
     }
 
-    if (now - last_response_ms > 100) {
+    const uint32_t last_request_delta = (now - last_request_ms);
+    const uint32_t available = port->available();
+    if (((last_request_delta > 150) && (available > 0)) || // nothing in our input buffer 150 ms after request
+        ((last_request_delta > 90)  && (available == 0))) { // we requested something over 90 ms ago, but didn't get any data
         port->discard_input();
+        last_request_ms = now;
         // Request an update from the realtime table (7).
         // The data we need start at offset 6 and ends at 129
         send_request(7, RT_FIRST_OFFSET, RT_LAST_OFFSET);
diff --git a/libraries/AP_EFI/AP_EFI_Serial_MS.h b/libraries/AP_EFI/AP_EFI_Serial_MS.h
index 533d2dab93..89dd018bf0 100644
--- a/libraries/AP_EFI/AP_EFI_Serial_MS.h
+++ b/libraries/AP_EFI/AP_EFI_Serial_MS.h
@@ -46,7 +46,7 @@ private:
     uint8_t step;
     uint8_t response_flag;
     uint16_t message_counter;
-    uint32_t last_response_ms;
+    uint32_t last_request_ms;
 
     // confirmed that last command was ok
     bool last_command_confirmed;