I had access to a general brand PCM reader (not the official GMC at the dealer) andwas cost free to me (the Chevy dealer wants US$67 for just reading the PCM). Using the reader, I noticed some interesting values from the recorded data, engine 100% hot.
Cooloant temp 72ºC or 160ºF (quite low in my idea, thermostat will be swapped soon, but data is in line with gauge reading)
Advance 20º (????) at 620 rpms (iddle). Moved to 35º at medium rpms
TPS up to 30% whith a little gas. 0% with no pedal
I failed to find A/F ratios, sensors reading variability, etc.
Any of you have some of the best values (standard or OEM values) for the 4.3. As MAF , Map readings??, etc.

 

This really is a loaded question... I can send you the log of my truck from alittle over a year ago... (or run another one sometime next week)

Problem is, both the MAP and MAF sensor values are dependant on environmental conditions as well as operational conditions of the engine (RPM, throttle position, etc).

 

If at that time the truck was fine (fuel consumption), that data may help me as a background reference. Thanks.

 

See the attached file. Problem is, this data was taken in November with no reference for outside temperature. Also, as you can see, I never went much over 50% throttle during this scan. Good luck with the data...

 

Thanks. Some few things can be observed:
Coolant temp (probably is not exactly related with local air temp) is always around 190-195. My coolantis below that and intake air temp was 57º (160ºF, at the engine bay whenhot, parked).
Iddle rpms are similar yours.
Timing advances are similar at iddle (20º) and yours wentup to a little over 40º while accelerating.
I got your references for the TPS % (2500 rpms =50% or 2000 rpms=25%, but depending in the engine load)
So part of the data can be used as references in this moment. Maybe some other guy can bring additional data.

 

Bump...None?

 

Not many people have scan tools that can log the data...

 

What are you trying to do? You won't find air/fuel ratios, but you'll should be able to view the O2's as millivolts.

 

Just trying to get informed for the next time I plug/read the PCM. At the mean time I swapped the thermostat (nothing looked bad in the old OEM 195º, Stant195º is in place) and now temp is higherat the gauge and fuel consumption is estimated to be better (few kms only). swartlkkgave me some good indications but a few more isn't bad.