Change the bit window (upper right corner) to show things like closed loop, BLM enable, power enrichment enable, etc. There is no value in displaying the status of things like windshield heat, etc. Show the important stuff.

May just be a consequence of looking at a single frame, but in the bottom screen shot, the left and right O2 sensor readings are both lean. That was the problem that appeared in your full data log.... looked like it was running out of fuel whenever you went WOT.

Did you ever check the fuel pressure UNDER LOAD?

 

My injectors are actually stock, maybe that duty cycle is part of the problem. Those still confuse me a bit, although I get the theory. I did find elsewhere that the PCM does calculate WOT of starting TPS voltage and is WOT at around 3.8 and above.

The cam change was a few years and a few thousand miles ago. The only change near the time this started was putting in a remote battery disconnect which had not been tested at the time the problem arose.

My alt charge wire was ran to the battery side of the disconnect and all the ones at the alt tied together in a junction block near the alternator. I have since changed back as I thought the voltage change from 13.8ish to 13.2ish may have caused it.

My truck has the same MAS so I'm going to swap to test. I also have another TPS & Ignit Control Module (thinking maybe it's a heat soak thing) so I may swap them. I am running all MSD, Digital 6, coil & wires.

Thanks for your help Bob.

 

Freds (post # 16) checking FP under load is a very good point. I was looking at the injector BPW to see if the PCM was trying to add more fuel if the pump is dying out, it does not show that. However not all things are evident in a trace. What pump setup did you install in the Nova ?
I was also scratching the bottom thinking about intake or exhaust restriction, I did see you hit 3750 at record 1414, so the car will go over 2500 at times.
Some other minor points, do you have a P/N switch on the shift linkage ? Your trace shows you are in 'D' all the time, even at startup, as normal crank start-up bumps the KC thousands , but should not retard the spark. You are getting 3-4* retard during start-up. P/N also effects idle speed.
Noticed your Closed TPS timing is a little low for your cam, most people set it to the 30-34 * at 400, 800 and 1200 in the Closed TPS closed tables, probably why you MAP at idle is a little high. This allows a lower idle in drive, makes it more drivable. Yours looks stock (around 20*) Could ask your tuner about that, he may have had a reason to lower it.

 

Fred - I miss your post (16), showing my tuning ignorance I didn't realize you could change those cells in the upper right. I will do that. I have watched the fuel pressure gauge while driving and it's typically in the upper 30's. I disconnected the vacuum feed and ran it at 44 and it never changed.

Bob - I've got a Holley 255 lph in tank pump. I do not have a feed going to the PCM for gear indication.

I've had laptop issues lately and am waiting for a new USB cable to come in this week. I'm planning on making some time this weekend to swap some parts (MAF, TPS, O2) and do some more datalogging getting some more data. I will pass that on to MadTuner to see if he has any input.

Thanks for your help guys.

 

I took the car for a test drive yesterday after swapping the MAF but the problem came back. I was able to run it up to 5700 without a problem and verify that fuel pressure only went up from the normal 36ish cruise pressure peaking at about 42/43 through first & second gears.

On the return trip I was going to pull off and shut down for a few minutes and see if developed again. Just as I did the fan kicked on. This may be irrelevant but I'm tying to be as detailed as possible. I let it sit for a couple minutes and restarted. At the stop sign 1/2 block after start up I ran it up on the convertor stall to about 2200 or so without an issue, which is what I was doing when the while problem developed. I dropped it back down and went to leave and the problem was back. This time it did something it hasn't done before, while stumbling it suddenly came back then stumbled again a couple times. Unfortunately I did not have the datamaster hooked up at the time.

I let it cool, swapped MAFs back and removed the wide band O2 and rewired so the computer reads the stock sensor. I'm going to add a bung and run the wide band independent. I tried driving again and no change, now it acts up below 2500 as well.

I am emailing the tuner to see if he has any thoughts.

 

You got a bad connection somewhere or a bad sensor. I've never seen a car behave like that.

 

When I built my new motor I had a clogged cat. I had a 2500 RPM "limiter" due to that clogged cat and no matter what I did I could not get above 2500 RPM until I took the catalytic converters off. Once I did that I noticed both were clogged big time.