I read Injuneer's website and he said the O2 readings should have no more than a 30mv difference between the two.

At one moment in my datamaster log, the left reading is 635 while the right is 959. One other reading shows the left at 404 and the right at 71. I assume from these readings that I really need new O2's.

One other question I have, do the readings of the o2 sensors have any effect on spark retard. I started out tonight having a slight constant knock. One time up to 5 deg., but when I got on the freeway, and made my way back to town, I had no retard whatsoever. Any ideas what could cause this.

Thanks for any help anyone can give me.

 

He meant there shouldnt be greater then 30mv difference at WOT. During normal driving the O2s should be fluctuating several times/sec. What you need to worry about is if they stick in 1 spot during closed loop or if they dont fluctuate thru the entire 0-1 volt range but say only go from 300-500mv.

 

At WOT i had these 3 different readings...

630 955 left/right
626 955
635 959

I had an error code saying that the left o2 had failed, but cleared it and it hasn't come back yet.

 

You should be doing more data logging to check your O2s. One thing that you can do is to swap the front O2s from left to right. If the 630mV O2 remains 630mV when installed in the other side, Then one of the O2s are bad. I would assume that the 630mV sensor is the bad one, but not necessarily.

 

Sounds like that sensor is dying but I would first do like was already suggested and swap them from side to side to see if the problem follows the sensor.

 

You have two possibilites on the O2 sensor readings.... either the left side is running dangerously lean, or the left side O2 sensor/wiring is screwed up. The right side might actually be running excessively rich or something wrong with the sensor as well.

What do the O2 readings look like in closed loop/part throttle? Are they cycling as described in my writeup? What do the BLM's look like for representative Cells?

Also, what the the SPECIFIC code you got for the left O2 sensor?

If your engine is really running lean on one side, its conceivable that it is running lean enough to cause knock, and cause the PCM to retard the timing. But there's not enough info to pin it down farther than that. Did you get "slight constant knock" at part throttle? WOT? Both?

 

Error code was MALF 13: Lefot O2 Fail.
Here's a small look at what it was at a varying
Again, thanks to everyone who has taken the time to look at this.


[CODE]
Left O2 mV Right O2 mV Spark Retard RPM TPS %
480 728 1.4 1825 21.6
480 728, 1.4 1825 21.6
484 737 1.9 1650 21.2
488 764 0.0 1575 4.3
488 764 0.0 1550 3.5
[/CODE]

WOT
[CODE]
Left O2 mV Right O2 mV Spark Retard RPM TPS %
453 892 0.0 1200 8.2
586 790 0.0 1400 19.2
453 124 0.0 1700 25.5
448 120 0.0 1800 27.8
444 147 0.0 1850 31.0
444 613 0.0 2025 43.1
417 528 0.0 2150 53.7
408 866 0.0 2225 60.8
533 813 0.0 2300 66.7
604 972 0.0 2350 69.8
617 959 0.0 2425 75.7
617 955 0.0 2450 76.1
622 955 0.0 2475 78.0
626 959 0.0 2550 91.0
622 955 0.0 2600 90.2
626 959 0.0 2625 89.8
630 955 0.0 2675 100.0
626 955 0.0 3200 100.0
635 959 0.0 4450 100.0
639 968 0.0 4200 79.2
639 950 0.0 4375 82.7
639 963 0.0 4500 74.9
639 955 0.0 4575 72.9
648 959 0.0 4775 69.4
653 963 0.0 4900 65.5
[/CODE]

and my BLM's
[CODE]
LTerm-LC STerm-LC Spark Retard RPM TPS %
Counts Counts Degrees RPM Percent
117 130 2.2 1475 20.4
128 134 3.5 1525 51.4
128 123 3.4 1525 49
128 120 3.4 1550 35.3
124 123 2.6 1550 21.6
117 120 0.9 1575 14.1
113 128 0.3 1575 12.5
113 130 0 1575 9.8
113 122 0 1575 9.8
113 120 0 1575 9.8
113 128 0 1550 9.4
113 129 0 1550 8.6
113 118 0 1550 8.2
112 126 0 1550 8.2
112 128 0 1550 8.2
112 130 0 1550 8.2
112 132 0 1550 8.2
112 135 0 1550 8.2
112 127 0 1525 8.2
112 126 0 1525 8.2
112 135 0 1525 8.2
112 137 0 1525 8.2
112 127 0 1525 8.2
112 136 0 1525 8.2
112 137 0 1525 9.8
112 128 0 1500 11
112 125 0.1 1500 11.8
112 136 0.1 1525 11.8
112 125 0.1 1525 11.8
112 134 0.1 1525 11.8
112 126 0 1525 11
112 124 0 1525 9.8
112 132 0 1525 9.8
112 134 0 1525 9.4
112 123 0 1525 9.4
112 131 0 1525 9.4
112 132 0 1525 9.4
112 123 0 1525 9.4
112 120 0 1525 9.4
112 129 0 1525 9.4
112 132 0 1525 9.4
112 121 0 1525 9.4
112 129 0 1525 9.4
112 130 0 1525 9.4
112 121 0 1525 9.4
112 128 0 1525 9.4
112 129 0 1525 9.4
112 119 0 1500 9.4
112 127 0 1500 9.4
112 129 0 1500 9.4
112 118 0 1500 9.4
112 126 0 1500 9.8
112 128 0 1475 9.8
112 118 0 1475 9.8
111 126 0 1500 9.8
111 128 0 1475 9.8
111 119 0 1475 9.4
110 117 0 1475 9.4
110 128 0 1475 9.8
110 130 0 1475 11.8
110 122 0.2 1500 12.5
110 120 0.2 1500 12.5
110 130 0.3 1500 12.5
110 132 0.3 1500 12.5
110 121 0.2 1500 12.5
110 132 0.2 1500 12.5
110 123 0.2 1500 12.5
110 131 0.3 1500 12.9
110 133 0.3 1500 14.1
110 122 0.6 1500 15.3
117 124 0.8 1525 16.1
117 122 0.8 1525 16.1
117 120 0.7 1525 15.3
111 134 0.3 1525 12.9
110 123 0.3 1525 12.9
110 134 0.2 1525 12.9
110 125 0.3 1525 12.9
110 133 0.2 1525 12.9
110 135 0.3 1525 12.9
110 124 0.2 1525 12.5
110 133 0.1 1525 11.8
110 125 0.1 1525 11.8
110 133 0 1550 11
110 134 0 1525 9.8
110 125 0 1525 9.4
110 123 0 1525 8.6
110 134 0 1525 8.6
110 136 0 1500 8.2
110 125 0 1500 8.2
110 134 0 1500 8.2
110 136 0 1500 8.2
110 138 0 1475 8.2
110 140 0 1475 8.2
111 130 0 1475 8.2
111 138 0 1475 8.2
111 139 0 1475 8.2
112 129 0 1450 8.2
[/CODE]

 

Will a bad O2 cause the car to stumble when starting it up. I just went outside and had a hard time getting the car to run. It just had a really bad idle but when i turned the car off and back on, it went fine.

 

Looks like the left O2 sensor is near dead. Definitely isn't responding the way it should. The artificially high readings are causing the PCM to start to pull fuel out using the BLM's. That is causing it to run lean at part throttle. It shouldn't cause it to run lean at full throttle, because if the BLM's are pulling fuel in closed loop, it will default to a value of 128 when you enter power enrichment mode.

The left sensor is either faulty, or there is a voltage leak between the wires.

 

Thanks a lot for taking the time to look it over.