vehicle - 1987 W100, 318, 4 pin connector electronic ignition system, edelbrock 600cfm carb with performer intake and cam.
I just put a new carb, intake maniford, timing gears, and cam in my truck and checked the timing which was 8 BTDC as list on the label. I increased the throttle gradually up to 4500rpm and the timing never advanced to more the 18 BTDC. There is no vacuum or mechanical advance on the distributor and as far as I can tell there are no sensors connected to the computer, just the ballast resistor. Reading the Haynes repair section on this system gave me no answers. Can someone tell me how the computer adjusts the timing and if the computer might be faulty? I did not check the advance before installing the new carb so it may have always been like that. Truck has always been sluggish but I thought that was from the gearing and 4 wheel drive. Would changing the distributor to one with weights and a vacuum advance give me better economy or performance? I know the vendors selling them say it will but what else would the say. Thanks, George