Since 1996 I have been intrigued by the Rover Efi SD1 Hot Start Problem caused by Fuel Vaporization, then in 2006, Campbell Macrae found a 1986 Technical Newsletter that Rover sent to its Australian Dealers which threw new light on the subject. The following extract defined the Rover problem:

Quote Fuel vaporization can occur at the injectors when a vehicle with the engine at warm to hot operating temperature is parked in the sun for a short period and then restarted. Should a customer complaint of this nature be experienced, the following action ------- etc, etc. Unquote

Whatever solution Rover devised, it had to work seamlessly from the ignition key in order to satisfy indignant owners suffering this hot start problem every time the sun shone on their executive car just a few years after they purchased it. Not good PR methinks?

Although the original circuit diagrams are still missing I have pulled all the other loose ends of the story together to explain the physics of what happened and how the Rover solution worked. I hope the science bears scrutiny regarding this somewhat mythical problem.

Read or download the article in PDF format from here (37kb)