Make sure the computer is from the same age of car as they come with different software releases (referred to as REL)- I believe they cause problems with the fuel sender.

Just a tip, pull out your clock and check the wiring behind if you have 5 wires you need to add some wiring, if you have 12 or 13 you have the wiring in place.

Check here : http://www.mirez.co.uk/Trips.htm

Hope this helps