funny plug? 2.6 190

[olly-civic]

hi iv got a 2.6 190E 1990, by the diagnostic plug there is another plug that fits in two ways one pointing to N the other S any idea what this does?

 

[Unleashed]

It's a fuel type switch. If you flick it to S, you can run super unleaded (i.e Shell Optimax) without damage to your engine. If it's on N, you can run the normal Tesco stuff.

 

[olly-civic]

odd how a plug can determine the fuel i use tho? especialy on such an old primative fueling system?
anyways thanks for that