At the previous emissions inspection, my 1986 XJ6 failed. Timing at 6 degrees BTDC, which I thought correct at that time. I put a new cat on and it passed, just barely on NO2.
This year I checked the timing and it was at 6 degrees BTDC. Checked the manual and it showed 6 for some cars, but when I checked under the hood, it said 17 degrees BTDC for my car. Retimed to 17 degrees BTDC, and it passed with flying colors. But my mileage has dropped from 20 mpg to 13-14 mpg.
I guess I will just have to change the timing every two years for emissions. Anyone have any idea how close to TDC I can go? or is 6 degrees BTDC as far as is safe?
Erunner
Submitted by zurdo_1@univis… on Sat, 03/24/2007 - 10:03
Submitted by dougdwyer@adel… on Sat, 03/24/2007 - 00:13
timing and mileage
Odd. More intitial timing will usually increase fuel economy.
Doug Dwyer
Longview Washington USA
1995 XJR
was the car warmed up when you took it for inspection? it needs to have gone through many warm-up-cycles for emissions to stabilize, as was the case with my 1984 when it failed emissions-testing once. I was told by a Jaguar tech to drive it for at least 1.5 hours before taking it to the testing station. I did and now it passes everytime.