Curious if anybody has a stock ~2007 Buick Lucerne 3800 file... I didn't see one in the repository. My 170,000 2004 Grand Prix 3800 seized up due to coolant leak into the oil, it ran great, no knock up until that point.
I replaced it with a 50,000 mile 2007 Buick Lucerne 3800, it was almost a direct swap... only things slightly different were the oil pan and exhaust manifolds... The 2007 Lucern oil pan is cast Alum and a bit bulkier than the 2004 steel pan, so I had to grind 1/4" deep x 1" long area out of the bottom motor mount... that's it. The Exhaust manifolds are an updated design... they end up not needing replaced, but look a bit different is all.
According to Autozone, all of the sensors are the same except the Throttle Body and injectors so I swapped those pieces.
It started up and runs great, however now I notice I have 5-7 degrees of knock retard under acceleration, say 1/2 throttle mainly, before PE, around 90kpa and higher manifold vaccuum... I never had this before with the stock motor.
Fuel trims look the same as the old motor for the most part.... little different but not more than 5-6% adding or subtracting...
Any ideas? I wanted to look at the spark map on the 2007 Lucerne... wonder if the cam or compression is slightly different.