I recently bought a 1986 Trans Am with the LB9 305 TPI and I've been trying to figure out why exactly it won't start. It'll fire on the first crank and then completely flood and refuse to fire any more. There's a strong gas smell as well, so I'm certain of it's flooded state.

What I've tried:
Unplugging TPS, MAF, various injectors.
Inspected the fuel pressure regulator (the diaphragm appeared to be perfect and the regulator itself looked fairly new).

Can anyone offer some advice? Thanks!

 

If there was no fuel bypassing the regulator and pumping into the vacuum hose, that should be good (for now).

In case there is some issue with the cold start injector and control, unplug the CSI and see if that corrects the flooding. The control is located at the front of the intake, just below the throttle body and to the right (passenger) side.

A second possibility is shorted wiring in the injector harness (service injectors) causing them to go static and rapidly dump fuel.

 

That's awesome advice, thank you! There was a bit of fuel smell in the regulator hose, but no liquid fuel that I could see. I'll give the cold start injector fix a shot tomorrow, hadn't considered that before! As for shorted injector wires, how might I go about testing for that without pulling the wires from the harness?