I finally finished my MAP conversion. I went out for a drive and let the car war up drove it around for 20 mins. I wanted to check if my car is going into closed loop so I unplugged the O2 sensor when I was in my driveway and in park. I expected the SES light to come on but it did not. I thought you might have to be moving to trigger the SES so I drove it into the garage and still no SES light with the O2 sensor unplugged.

Can someone please tell me if the SES light should come on right away when the O2 is disconnected?

I want to make sure my car is going into closed loop as this whole ECM change over I went through was to make the car go into closed loop. The mechanics who performed the conversion did not change the knock sensor or ECM when they converted the car to MAP from MAF. So it was running open loop ever since. I was hoping that I would fix this but looks like I failed.

 

A better way to determine closed loop is to put a digital volt meter between the O2 sensor output & ground. The voltage should swing between approx 100 mv & 900 mv about twice per second in closed loop mode.

Tim

 

Tim, I checked the voltages like you said. I came home after driving the car for about 30 mins and done the test.

My result was that I got a reading of .870 volts steady. It did not go up or down like you said. well it did go down to like .865 and then around .870 but not big jumps like you said shoul dhappen if I am in closed loop.

I have run out of options what could be causing my problem. I have checked all sensors that could be causing this but they are all fine. The O2 sensor is only 6 months old and doubt it is faulty.

The only thing that I have done is I have got a 160F thermostat in the car. But the temperature should still rise above what is needed to go into closed loop. I think I was told it needs to reach around 130F before going into closed loop.

Do you have any other tests I could do or check?

Thanks

 

Just to make sure I did the test correctly this is what I did.

Unplugged 02 sensor connetor.

Put in positive lead into O2 connector
Put black lead onto ground
got a voltage reading of .870 volts

That is the correct way right?