Hello: Hmmmm! I don't know that much about a 96 Caddy but here are my thoughts. Earlier GM cars had 2 fuel pump energizing paths. One was from the fuel pump relay and the other was from an aux oil pressure switch. The idea was that if the fuel pump relay failed, the oil pressure switch would allow the fuel pump to run as long as there was I think greater than 4 pounds of oil pressure. On earlier fuel injected GM cars when you first turn the key on you could hear the fuel pump run for approx 2 sec or so then shut off until the engine was started. Possibly yours does the same, you have to listen very closely, possibly have someone listen in the gas filler for the pump running when you first turn the Ign switch on. Possibly also after sitting for some time the fuel pressure bleeds off to 0 or the fuel pressure sitting on the injectors for some time is leaking past the injectors and dumping a lot of fuel into the intake manifold causing a very rich first start mixture. If the pump relay is bad, then cranking the engine until oil pressure builds to the point to close the aux oil pressure switch before the fuel pump runs? These are the things that comes to mind, seems like a fuel delivery problem at first thoughts.
Saturday, January 14th, 2006 AT 11:02 PM