2G How to test for open/closed loop

[XxrusianxX]

So I have two problems, one is that the car will not pass inspection due to the sensors not being ready. Tried waiting for 3 weeks and still not ready. I see one of two problems. One the ECU is not storing any memory by loosing power at ignition off or just bad ECU, or it is not getting any sensor information.

The other issue is I don't have access to the proper scan tool to test open or closed loop operation. So I need a way to test for that with out a scan tool. Testing for closed loop operation should tell me if the ECU is getting the sensor information.

Any suggestions on this guys...

 

[sbiggi]

O2 voltage should cycle at cruise and idle.
Then go constant (or close to) at WOT.

easy test. All you need is a blinky autometer gauge or a voltmeter to test for that.

-Seth

 

[XxrusianxX]

and what is it, like 13 min after start that it should go in to closed loop

 

[dsm-onster]

and what is it, like 13 min after start that it should go in to closed loop

Whenever you get to 180+ degree coolant temps (someone chime in and correct my number here, if I'm wrong). This may very well be 13 minutes after you start up in your case. . .

 

[XxrusianxX]

thanx guys this help a lot i will let you know what i get

 

[Ian M]

So i have two problems, one is that the car will not pass inspection due to the sensors not being ready

This is for a emissions test?

I think the problem you have is that the OBD 2 readiness monitors arent setting. I think you have closed loop and readiness monitors confused.

There are several monitors in the OBD 2 system,to check individual components; O2 sensor,EGR,Evaporative,catalytic converter,etc. The monitors pretty much are a self check of each system.

If the power is interrupted to the ECU,the monitors have to run a check each system,and the system has to see certain driving conditions met. Every OBD 2 equipped car has a specific drive cycle that has to be completed. If every thing is good,the monitior is set and your are good to go. If something is wrong,the Check Engine light comes on.

Once the monitors are set,they should stay until the power is inturrpted to the ECU,although some are re-set every time you shut the car off. I am not sure about a 2g car,but on the '97 3000gts,the monitors are reset each time the key is turned off. I found this one out the hard way on a customers car.

I suggest getting a copy of the required drive cycle to reset the monitors from the station you had it tested. If they do emissions repairs,they will have a large book with the specific drive cycles for OBD 2 equipped cars. The book will tell you what exactly to do,and if the monitors reset each time you turn the key off (as in the case of the '97 3000gt),it will tell you that as well.

 

[XxrusianxX]

This is for a emissions test?

The test was done by me at the dealership i work at, and i just found the problem today, when i traced the wire going to terminal 80 (backup power) there was a wire poorly tapped in to it, so the ecu was loosing power and loosing all its adaptive memory. after a little soldering the voltage at the contact was a steady 12.4v and i think this should do the trick