I had alway thought of triggering the 5th injector off of the fuel enrichment switch on the throttle body. However I don't think the placement of the 5h injector would deliver a uniform amount of fuel to the cylinders at high RPM. Alan -- To subscribe or unsubscribe, send email to scirocco-L-request@privateI.com, with your request (subscribe, unsubscribe) in the BODY of the message.