billschroeder5842

So, I'm having great fun trying to figure out my WinALDL reader for my '82. So many charts and numbers across my laptop it seems confusing at times.

Yesterday it told me that O2 sensor was bad, but that struck me a funny as my car runs great.

So, I picked up a sensor and replaced the fault. Now that the O2 is fixed, what can I (or should I) look for in the way the car runs?

I drove it around about 5 miles and it felt pretty much the same.

terry82

what numbers did it give you that made you think that the o2 sensor was bad? what are the new numbers?If your numbers changed after you went to a more open exhaust you may have to go to a heated o2 sensor.

billschroeder5842

The reader showed a fault code on the "13 oxygen sensor" (a check mark) in the matrix.

I did change the exhaust but it is a cat back system after the factory cat.

vbgod1

Welcome to the world of scan tools and one of the first computer controlled cars. I was going to say, "Now you know how we felt in 1982", but we didn't have the Internet to go look for answers.
If the car is running well, the first thing I would do is record all of the "good" readings, as a reference for when it runs bad.

Keep in mind, the scanner does not tell you a part is bad, it merely does not like the reading it sees in that circuit. Had a student replace a coolant sensor from the zone twice, then a third time from O'r, and still had the light on. We hooked the scanner up, and the circuit was reading like 60 below 0 on a summer day. The connector had a broken wire, got it fixed and he was good to go.

Having good readings is a start. Research into "Normal" readings may take a while.

billschroeder5842

This is what I have. I just don't know how to read it.

billschroeder5842

More!

vbgod1

FWIW... Negative numbers across the top, and the word Datalogger, make me think it functions like a black box. If there is a hiccup, you can scroll back a bit and see what was logged for the event.
Coolant temp, speed and rpm, you know, and should be close to actual. IAC is idle air control, the computers attempt to regulate idle rpm. That is when you crank the idle up, the computer runs it back to where it wants it. MAP is ManifoldAbsolute Pressure, or the vacuum reading the ecm sees. O2 is Oxygen Sensor, should go above and below 5v, if working. INT and BLM are short and long term richening or leaning of the fuel to try and regulate burning. Rich/lean counter is how many times O2 sensor is above and below 5v.

lionelhutz

The sensor data is the best to start with. Here's a quick breakdown.

IAC - idle control. A higher number allows more air to the engine to make it idle at a higher rpm.

Coolant Temp - should be self explanatory.

Speed - should be self explanatory.

MAP - this is the pressure in the intake manifold. Use or follow the 0 to 100kPa scale. O kPa is the same as 29.9" Hg (a vacuum) and 100 kPa is the same as atmospheric pressure or 0" Hg. Like watching a vacuum gauge, this will be lower with the throttle closed and higher with it open.

RPM - should be self explanatory.

TPS - the throttle position sensor. The voltage goes from approximately 0V to 4.5V. Each car will vary so with the engine not running cycle the throttle slowly open and closed and this voltage should follow nice and smoothly. Any jumps in the voltage are indicative of an issue.

INT - the integrator of the O2 sensor feedback loop. It will constantly go above and below 128 to indicate the fuel is rich or lean.

O2 - when the controls are in closed loop this should just constantly swing above and below 0.45V. Below is lean and above is rich. When in open loop (like your foot to the floor) this should be above 0.45V indicating the engine is getting extra fuel. Never expect to use the O2 sensor to read anything except rich or lean of stoichiometric.

BPW - the pulse width of the injectors or how long they are open each time they are triggered. The system will likely trigger the injectors each time a cylinder fires.

BLM - this is the learned and stored fuel correction value. There is a small table in the computer that stores values based on RPM and MAP. It likely stores about 9 values. This is used so the computer can learn any fuel corrections and more quickly get to the "ideal" air fuel ratio as the throttle position varies. This basically stores how much the INT had to be above or below 128 to make the O2 start switching.

The computer will try to run in closed loop most of the time. What happens in closed loop is the computer will constantly be driving the system back and forth between being slightly lean and slightly rich. It slowly adds fuel until the O2 sensor will suddenly switch to indicate rich and then it slowly removes fuel until the O2 sensor switches back to lean where it begins to add fuel again.