Boy, I was confused there for a moment. I just answered a similar question yesterday for a Caravan. Thought I was getting "old-timer's disease" when I read "Spirit" in my e-mail notification. :)
With as much fuel that's being dumped into the engine, something is more seriously wrong than the O2 sensor. Look into the throttle body while the engine is running. You should see a nice cone-shaped spray of fuel. If you see large droplets of raw fuel, something is wrong with the pressure regulator or its o-ring. Look for raw fuel on top of the regulator too. If the spring-loaded diaphragm is leaking, (which I've never encountered or heard of), fuel will run through the air bleed hole on top of the unit.
Did this problem start all of a sudden or did it gradually get worse over time? Is it possible someone installed an incorrect fuel pump in the tank? Normal fuel pressure is around 14 psi for throttle body fuel injection systems but multiport systems can run over 45 psi. If fuel pressure is too high, the regulator will be overwhelmed and not be able to pass the extra fuel back to the tank fast enough. Also look for a restricted fuel return line from the throttle body to the tank. That will cause pressure to go too high. Excessive fuel pressure means too much fuel entering the engine.
I believe you are going to find a mechanical issue causing this much extra fuel, not an electrical problem. Watch the spray from the injector nozzle while a helper turns off the engine. The spray should stop instantly. If it continues to dribble with the engine stopped, the injector is leaking and is unable to control fuel delivery properly. They normally give such little trouble, a good used one from a salvage yard would be a satisfactory replacement.
Friday, July 23rd, 2010 AT 11:49 PM