MAF is the one thing that looks off to me too. We don't use lbs/min here in the UK so the numbers aren't familiar to me but what jumps out is the air flow in image 2 is higher than than the other images yet the throttle is closed in image 2. It's difficult to say for sure if that's significant from a static data capture though. Maybe the throttle had only just closed when the capture was taken so there was still air flowing through the sensor. I certainly think some further testing of the MAF would be worth while to try and confirm if the MAF input to the PCM is correct. Perhaps try a test drive with the MAF sensor unplugged to see what effect it has. The PCM should use a calculated substitute value for MAF when the sensor is disconnected.

 

Here's a MAF table from a Ford. It shows how they should read with the airflow. Hyundai's should be similar. #mass /tic is clock speed dependent on the ECU processor.

 

Well prompted by Red's observation on the MAF readings yesterday I spent many hours ringing out the wiring between the MAF connector, the PCM, the 'common connector' and ground.
I am confident I had voltage where I was supposed to have voltage, had ground where I was supposed to have ground and had continuity where I was supposed to have continuity. I then dowsed the MAF & IAT with special cleaner multiple times and put it all back together.

I don't know whether I caused more damage or just matured whatever damage already existed but the screen shot from the run after I put it back together shows a lot of dead sensor behavior and the open loop condition returned permanently.


At this point I am thinking the PCM may toasted or at best, sporadic and may have been the fault all along. I wish I could test that theory before spending big $ on a new or used PCM.

What advice can you suggest at this point?
And I certainly thank you all again for your time and interest.
Tom C

 

Disconnect the MAF and see how it runs in default mode. If it's bad and the ECU is good it will run and throw a code. If the ECu is bad who knows what will happen.

The electronics in the MAF can go bad giving non linear outputs.

 

I suppose the air tube between the air flow meter and the manifold has been checked for cracks? A light air pressure and soapy water can help identify any leaks.
With the maf disconnected it will run but have some poor driving habits but as RR said it will log a code.
Just has a very quick look at hat last post and the air flow is zero? I find thew best way to test them is by measuring frequency not voltage.

 

This is better than a Tom Clancy novel. But really? Why leave me hanging like this? That's just cold but perhaps genius. Genius if, after getting folks like myself so interested, that we'd pay money to find out how the story ends! It is now 2019 and Trump has been Pres for two very very long years. There has been nothing to smile about for so long that I believe my face would freeze if I tried now. But, regardless, what ever was the final fix in your situation????

 

The guy hasn't been back on this forum since he disappeared years ago. There are probably thousand of unfinished posts with unresolved outcomes.