I'm not sure how the computer detects the EGR valve operation, but I do know it is very difficult to "wire around". Just clean the intake as required and use synthetic oil.

A clean air intake for the EGR won't fool the computer, it's looking for a reduction in combustion temp.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!