Thought I was dealing with a bad fuel pump, but, now I'm not so sure. Car would start well cold, run good for about 1/2 hour, start to stumble when I gave it throttle, then finally die and refuse to restart until it cooled off. I finally got the new fuel pressure guage. Hooked it up and turned the key "on". Shows about 43 psi. A tad low, put still in the normal range. Start it up and it goes to about 37 psi, but, jumps to about 42 - 45 when I open the throttle. Again, a little low, but, acceptable. Leave it run about a 1/2 hour and it starts to run sour. Open the throttle a little and it stumbles. I go to check the gauge, figuring it would be tanking out and it's still 37 at idle, 42 - 45 with some throttle. OK. Time for the scan tool. So, I shut it off, slap on the old auto xray. Of course by this time, it's warm enough where it won't start, so I can't get any real time data. I scan for codes and there are none. Run through everything that you can with key on, engine off and one thing jumps right out at me: The oil temp shows MINUS 39 degrees F. I didn't even know there was a sensor for oil temp. Could this be the source of my problem and where the hell is it located? I can't find jack about it in the manual.

 

So, I figured out that my auto xray doesn't know crap about oil temp, but, I got the car restarted and got some data, but, am unsure how to interpret it. I searched the archives, but, found nothing to help me. So, I hope you guys will give an old man a hand!
OK, here goes:
92 T/A 'vert 305 TPI automatic ... NO codes shown
I won't post everything I got 'cuz I know some of it doesn't apply here, (TCC locked, fans on, etc.)

Coolant temp 198.9 deg F
TPS .56 V
RPM wandering between 600 - 800
O2 sensor 410mV - 450mV
O2 cross counts 82
Block learn 150
Block learn cell 4 (not sure what this is)
Integrator 128
Idle air mtr pos 65
Map sensor 2.03
MAT 113 deg F
EGR duty cycle 0%
CCP duty cycle 0%
Batt Voltage 13.9
Fuel pump sense 13.7
Learned Idle Pos 63 steps
Spark advance 11.2 deg
Knock sensor 1
Knock retard 0 deg
Injector pulse 3.1mS
O2 sensor not ready
Learn Control Disabled
Rich lean flag lean
Loop Status open

So, it's obvious that it's running lean, but, the block learn/integrator numbers confuse me. Shouldn't they both be trying to add fuel to the mixture? And, shouldn't the learn control be on if the computer was trying to correct a lean condition? And, I thought the computer went into closed loop around 165 deg F? I'm guessing that my O2 sensor is shot. But, is there anything else going on here? Why no codes? TIA

 

O2 cross counts seem low?

 

I'll assume those readings were with the engine running. I don't know anything about your scan tool but the O2 sensor not ready may be keeping you from going into closed loop operation.

http://www.gnttype.org/techarea/faq/BLMINT.html

 

OK. Ohmed the injectors and they all match and are the same hot or cold. Today I ran the car at 1500 RPM for at least a 1/2 hour to make sure the O2 sensor got hot enough to function correctly. Still shows O2 sensor not ready and in open loop. Coolant temp 203 deg F. Also, when it starts to stumble and die, injector pulse width spikes as high as 5 mS. Pulled a plug and it's starting to get a little sooty. O2 sensor still under 500, though. So, it sees lean but is running rich. I'm gonna change that O2 sensor and see what happens. Discuss, please.

 

The ECM is programmed to run rich in open loop and basically ignores the O2 signal until "ready", then will adjust the A/F ratio in closed loop. I think replacing the sensor will solve most of the problem.

 

https://www.thirdgen.org/forums/nw-i...ml#post2935651
More info. Thanks!