Dynamic EFI

Bringing TBI and Multi Port Fuel Injection to a New Level.

USB to Serial Adapter Latency Setup

Note: this procedure is for USB to Serial cables that use the FTDI chip set.

Once the included driver is installed (takes about 30 seconds) the latency setting needs to be changed. The following guide shows how this is done. This guide was created on an XP box. 

Be sure to leave the USB to Serial adapter cable plugged into the USB port while making this change.

First is to open the Device Manager. Here are two methods of doing this. Both are from a right click of the mouse.

Manage from Desktop ICON   -OR-  Manage from Windows Explorer

The left picture is from the "My Computer" desktop ICON.
The right picture is from Windows Explorer.

Be sure to right click the mouse to get the small drop down menu. Then click on Manage for the "Computer Management" dialog:

Computer Management Dialog

On the left pane click on "Device Manager", then move to the right pane and expand the "Ports (COM & LPT)" entry (click on the + in the box).

Right click on the "USB Serial Port (COMx)" entry, a drop down will appear:

Driver Dropdown Menu

Click on the "Properties" entry. The FTDI driver Properties dialog menu will appear.

Click on the "Port Settings" tab at the top, then click the "Advanced" button.

Driver Properties Dialog

 The final dialog will appear:

Advanced Settings

The "Latency Timer (msec)" setting is to be changed. Click on it then select or enter 10.

Advanced Settings, Latency Set

Click on the OK button, and follow back through the dialogs clicking OK in turn.


If the latency setting is left high the What's Up Display will be able to data log and do VE Learns and such. Where there will be issues is with flashing a new calibration. There will be intermittent failures in the process. Sometimes it will work, other times it won't. The flashing may work OK but then the verify fails.

Lowering the latency timer corrects these issues. With the proper setting there should never be a failure to flash, verify, or set the bank active.

Copyright 2006-2023 Dynamic EFI, All Rights Reserved.
No part of this document may reproduced in any form or posted on a web site without expressed documented permission from Dynamic EFI