Pontiac Repair: fuel mixing with engine oil, coolant temp, engine coolant

Question
HI I HAVE A 91 GRAND PRIX (3.1L V6).AFTER TURNING ON THE IGNITION SWITCH FUEL GOES DIRECTLY TO THE CRANK CASE THEN THE CAR DOESN'T START BECAUSE OF THE FUEL MAKING THE OIL THIN. I HAVE CHANGED THE REGULATOR, INJECTORS, MAP SENSOR, O2 SENSOR, BUT I STILL HAVE THE SAME PROBLEM. P.S WHEN I CHANGE THE OIL THE CAR WILL START AND RUN FOR 10 TO 30 MINS THEN SHUT OFF BECAUSE OF THE FUEL MIXING WITH THE OIL.

Answer
Hi
The only things I can think of would be
1) If the cylinders just fill up without the engine cranking (spinning over), then I would think that either the injector ground control circuits are shorted to ground OR the ECM is faulty.
Check the injectors with a noid light, see if the light stays on all the time, if so one of the two is the problem.
2)If the cylinders are filling up ONLY when cranking, I would check the Engine coolant temp. sensor, making sure it is reading the proper temp, and not reading too low (too low creates a rich condition).
Also, if the injectors are spraying directly into crankcase, they are not mounted properly OR the intake manifold is cracked.
I hope these SUGGESTIONS help.
Just advice.
Good Luck
Pawl