Cranks but no start solved

[crtrett]

I'm a retired mechanic but I met my match with my wife's Aveo. One day it just died on her in a parking lot so I towed it home. I reasoned (wrongly) that the fuel pump went out so I replaced it. What confused me was that when it first energized it would come up to pressure but still wouldn't start. I had a guy come to my house with all his computers and they told us nothing, no DTC's, nothing! In the end he told me it was probably weak spark so after he left I replaced plugs, wires AND the coil, still no start. I had it towed to a reputable shop, no answers, told me I probably needed an engine?
One day I'm bumbling around and I noticed all the warning lights came on when I turned the ignition on except the oil pressure warning light. Tore the cluster apart to find nothing so I replaced the oil pressure sending unit. Still nothing. Put a meter on the sending unit and had my son crank the motor, no change. So I set out to change the oil pump (wife wouldn't let me burn the car or give up). What an ordeal! Along the way I discovered, if your oil pan doesn't have a cork gasket, don't try to put one on, your bell housing bolts (yes the oil pan bolts to the bell housing . To make a long story longer it started right up! The ECU saw no oil pressure and wouldn't allow the fuel pump to supply pressure. What's crazy to me is, now my oil pressure light works! Why did the ECU not throw a code?! I fought this for over a month wanting to give up and burn the thing down. Hope this helps someone.

[Eg.h2o]

That’s one for the books. I did not know the oil pressure light was in that circuit, buuut when converting old mechanical fuel pumped carburetor vehicles to an electric fuel pump I always hook it up through an oil pressure switch so if the vehicle ignition is on, but not with oil pressure the fuel pump will not run. You know, safety third.
As for the oil pan gasket I used an Asian manufacture thin fiber type that fit and worked for me.