hey i have an 88 lo3 tbi and i keep on trying to set my spark timing to tdc then i tighten distributor but it keeps on moving , it advances on its own , whay does it do that and how can i get my engine to have a set timing ?

Did you unplug the EST wire before trying to set timing? It's Electric Spark Timing - these cars are computer-controlled timing - they constantly change the timing as different values are read from the sensors. The EST wire is on pass side, right by the strut tower - it's a single wire with a connector in the middle - this has to be unpluged so you can set your base timing (which should be zero degrees BTDC). You unplug the wire, start car, set timing, shut off car, replug connector, and restart car.

yes , i tried doing it like it says in the haynes manual book , first i unplugg my est plugg coming out of the harness on the passengers side , then loosen my alt . hold down clamp , the start the car and all the other stuff and after setting it to tdc , i tighten down the alt. hold down clamp , shut off the engine plugg in the wire and start the car again , then i doublecheck if its tdc but it advances itself 15 degrees and is running super rich , i mean white smoke rich . i set piston number one @ tdc and evrything else how the book says , but still white smoke , i even tried flipping the distributor 180 degrees but nothing , its startying to piss me off .. but why is it advancing and why is it runinng super rich ?