Stock L05 from van, ANLU bin, only mod is disabled EGR. Engine runs fine, no codes, but I can't get it running to closed loop for some reason. Any ideas, what could prevent it to go CL?

 

if engine temp is below 140f or the o2 is not between 5-600f you will not enter cl. A defective o2 will prevent cl.

 

The engine is at operating temperature, O2 stays steadily at 446-455 millivolts. Nothing seemed wrong actually.

 

The ecm has to see that its up to temp, so do a resistence check on the cts. Or use a scanner & look at the live data.

 

CTS is functioning fine, ECM sees the temperature correctly and engine is over coolant temp CL threshold. O2 sensor worked fine before engine swap, so I wouldn't blame it either.

 

Check the ecm grounds, should be at the back of the pass. side head.

 

there you go

 

Depending on what silicone you used you might have poisoned it

 

Only place where I used silicone, was the intake and I used there black Loctite, I have always used without any problems.

If I remember correctly then after getting hot, the sensor read around 800 mV before the 305 to 350 swap. I never thought that the 450 should be too low, I just thought the cold AFR was spot on.

 

Just sorted it out. Somehow I had damaged the sensor wire when I replaced the engine and it grounded the sensor output down. After fixing the wiring, everything works fine.

Now I have to sort out the reason why engine runs rich on medium RPM and MAP region. Does anybody know on what pressure GM is rating their injectors? My FP is 12-13 PSI at the moment, considering the service manual it should be OK.

 

If it is rich lower down the ve in that kpa area.