hi all i have a vl with a rb20det in it.. and i know that engineers wont touch it if it has an aftermarket computer in it... so my question is - can i tune an aftermarket computer in for the emissions test, and then just leave it in limp home mode to the engineers? just that the stock rb20det computer wont let it go over like 3000rpm as it leans out the fuel and at idle has it very rich...

So you want to use the aftermarket computer for the emissions test then swap the std computer in for the engineers inspection? If you "trick" the engineer into passing it by not disclosing a mod or you change something after he has passed it, your engineering certificate is effectively invalid.

yeah, effectivly invalid, and i doubt anybody here has their cars engineered after they install a afc or anything similar.... just that im running rich on idle and leaning out at about 2500rpm and wont go any further...