I'm a little confused by this. After driving and pulling into my driveway, I datalogged, in idle, about a couple of minutes after I put the car in park. I recorded the car going into open loop with the car hot @ 230*. I'm also trying to solve a lean condition and think these are related. I thought open loop happened only at start up until the car entered a warm operating temperature. Is it normal for the car to run in open loop @ 230* as I described?
thanks.

 

Do you have headers?
Where is the O2 sensor located?
CL is determined by several things including O2 sensor reading .If O2 sensor cools off and drops out of operation, engine will go OL regardless of actual engine temp which is why guys run heated O2 sensors in headers to keep them at operating temp
Were you getting O2 cross counts on your datalog at hot idle?

 

I do have headers, SLP 1 3/4. The O2 sensor is located down near the oil pan or oil filter. My cross counts we're 182 to 248 in closed then jumped down to a steady 4 in open loop @ the 230*. It is also running lean @ 17 AFR. Could the lack of the heated O2 be causing the lean condition?

thanks.

 

O2 sensor is cooling off below required 600 degree operating temp at idle and dropping out which is why you are going OL.
I would expect it to be rich if anything in OL.What other mods do you have?

 

I have the msd al6 box with blaster coil, and msd module, wires, new plugs. I have an AFP regulator but it is set to 43 psi. 70* thermostat. Most every other sensor on the car is new, EGR is new and the orifice is drilled out to .041 to allow more vacuum to it. Timing is 6*. This lean condition is causing the car to fail emissions at 15 mph. It barely passes the 25 mph but only when the smog guy revs the engine for several minute to heat up the cats (new magnaflows duals). Then all the numbers come down quite a bit. I can think of a couple things that have never been replaced: ECM and the temp sensor under the plenum. I've looked for vac leaks but can't find any. Maybe there's a vac leak so small that it is hard to detect. I've see foamed before as well. A very strange situation. there is something I'm missing but can't seem to think of what that may be.

 

I also have headers on my car but no heated O2 sensor, just the standard single wire. How do I know if my car is in open loop?

 

a scanner will tell you.

 

after alot of reading, it appears I need to add a heated O2 sensor and go from there.

 

could also just be a bad sensor...........common problem.

replace the sensor first

 

Or a paper clip in A and B with the car running.

 

So why does it only not work at idle ?

 

i have seen one wire sensors do some strange stuff,one car you could hold it at 2000 rpm hot and watch on the scanner and even hear it go from open to closed loop at 5 second intervals. the life expectancy of a one wire sensor is 30k miles.tell me how many times you have opened the hood of a obd 1 car and noticed that the sensor is original.............

i have headers on my car and my sensor is slightly below my oil filter and my car has no problems.

the sensor could be just about dead and needs to be red hot to get into closed loop.

they cost $18.00,and have a short life expectancy,no one in there right mind would bust out a scope and temp gun and waste there time.