diff --git a/test/Common.Tests/Utilities/TestConnections.cs b/test/Common.Tests/Utilities/TestConnections.cs
index 3364a0e021..3b7a870cf3 100644
--- a/test/Common.Tests/Utilities/TestConnections.cs
+++ b/test/Common.Tests/Utilities/TestConnections.cs
@@ -62,18 +62,15 @@ namespace Microsoft.AspNetCore.Server.IntegrationTesting
 
         public async Task Send(params string[] lines)
         {
-            var text = string.Join("\r\n", lines);
-            var writer = new StreamWriter(_stream, Encoding.GetEncoding("iso-8859-1"));
-            for (var index = 0; index < text.Length; index++)
+            var bytes = Encoding.ASCII.GetBytes(string.Join("\r\n", lines));
+
+            for (var index = 0; index < bytes.Length; index++)
             {
-                var ch = text[index];
-                writer.Write(ch);
-                await writer.FlushAsync().ConfigureAwait(false);
+                await _stream.WriteAsync(bytes, index, 1).ConfigureAwait(false);
+                await _stream.FlushAsync().ConfigureAwait(false);
                 // Re-add delay to help find socket input consumption bugs more consistently
                 //await Task.Delay(TimeSpan.FromMilliseconds(5));
             }
-            await writer.FlushAsync().ConfigureAwait(false);
-            await _stream.FlushAsync().ConfigureAwait(false);
         }
 
         public async Task<int> ReadCharAsync()
diff --git a/test/IIS.Tests/ClientDisconnectTests.cs b/test/IIS.Tests/ClientDisconnectTests.cs
index ee55959a93..9c8855be47 100644
--- a/test/IIS.Tests/ClientDisconnectTests.cs
+++ b/test/IIS.Tests/ClientDisconnectTests.cs
@@ -206,6 +206,7 @@ namespace Microsoft.AspNetCore.Server.IISIntegration.FunctionalTests
         [ConditionalFact]
         public async Task ReaderThrowsResetExceptionOnInvalidBody()
         {
+            var requestStartedCompletionSource = CreateTaskCompletionSource();
             var requestCompletedCompletionSource = CreateTaskCompletionSource();
 
             Exception exception = null;
@@ -213,6 +214,7 @@ namespace Microsoft.AspNetCore.Server.IISIntegration.FunctionalTests
             var data = new byte[1024];
             using (var testServer = await TestServer.Create(async ctx =>
             {
+                requestStartedCompletionSource.SetResult(true);
                 try
                 {
                     await ctx.Request.Body.ReadAsync(data);
@@ -233,10 +235,19 @@ namespace Microsoft.AspNetCore.Server.IISIntegration.FunctionalTests
                         "Host: localhost",
                         "Connection: close",
                         "",
-                        "ZZZ",
                         "");
-                    await requestCompletedCompletionSource.Task.DefaultTimeout();
+
+                    await requestStartedCompletionSource.Task;
+                    await connection.Send(
+                        "ZZZZZZZZZZZZZ");
+
+                    await connection.Receive(
+                        "HTTP/1.1 400 Bad Request",
+                        ""
+                        );
+
                 }
+                await requestCompletedCompletionSource.Task.DefaultTimeout();
             }
 
             Assert.IsType<ConnectionResetException>(exception);