2001 Saturn L200 Gas in engine oil.

I purchased a 2001 saturn l200 with 100000km that was always dealer serviced, I have the receipts. At 107000km I noticed gas in the oil and immediately replaced the oil. After 6 more km driving a hard tick developed and a garage informed me that I had spun a bearing on the crankshaft.

Now a new engine is in the car and after 600km there is gas in the oil again. The injectors and fuel rails are different from the old engine, but ignition control module and ecm are the same.

I was thinking change the ecm since I was told by a mechanic that the icm doesn't control the injectors.

Any insight greatly appreciated. Also where is the ECM located, on the firewall, or under the dash?