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Did you re verify that you do indeed have .25 volts at the 5 volt ref. wire (yellow) at the MAF sensor ??...did you try starting the car with the MAF sensor UNPLUGGED ??...well, this will have to be addressed at some point !!...it would be nice if you had a scan tool so you can see which modules you can communicate with and which ones you can't. If you don't think you can confidently check PCM power and grounds YES take it to a shop and let them try to diagnose this...if you want to check the ignition switch you can do a "voltage drop" check across the switch...take the red lead of your voltmeter and attach it to battery positive...take the negative lead and touch it to any of the 2 test points at the PCM fuse 16...read the voltage "drop" during cranking...should NOT be more than .1 to .2 volts ...do the same thing at the PCM B fuse 23 !!...don't have anything else for ya Bubba !!
Did you re verify that you do indeed have .25 volts at the 5 volt ref. wire (yellow) at the MAF sensor ??...did you try starting the car with the MAF sensor UNPLUGGED ??...well, this will have to be addressed at some point !!...it would be nice if you had a scan tool so you can see which modules you can communicate with and which ones you can't. If you don't think you can confidently check PCM power and grounds YES take it to a shop and let them try to diagnose this...if you want to check the ignition switch you can do a "voltage drop" check across the switch...take the red lead of your voltmeter and attach it to battery positive...take the negative lead and touch it to any of the 2 test points at the PCM fuse 16...read the voltage "drop" during cranking...should NOT be more than .1 to .2 volts ...do the same thing at the PCM B fuse 23 !!...don't have anything else for ya Bubba !!
Unplugging the maf didn't help, still reading 0.25v at maf. I'm fine with checking voltages, just getting frustrated.
I was talking to one of my co-workers who has a auto/electric repair shop on the side and he agrees about checking PCM power and grounds...if you can get down to the PCM and check that yellow MAF wire down there by back probing Pin 48 on the C1 (Red) connector with key on...see if you have the same .25 volts there also...maybe check some other sensors with a 5 volt ref. You can try ECT sensor by the #1 spark plug....and the AC sensor which is on the right side by the AC Schrader valve...it's forward of the high side Schrader valve and it's a 3 wire sensor...I believe the bottom of the 3 wires is the 5 volt ref, Don't be frustrated because even for a Pro this may take some time AND MONEY to figure out....have you disconnected both "Star Connectors" bus bars or "combs" I had pictured and jumpered the wires between the dark and light green wires ??...and like I had said if this all started after your tune and if the PCM was removed you'll have to get down there and start checking...good luck bro !!! ....this picture shows the Star Connectors jumpered !!
I was talking to one of my co-workers who has a auto/electric repair shop on the side and he agrees about checking PCM power and grounds...if you can get down to the PCM and check that yellow MAF wire down there by back probing Pin 48 on the C1 (Red) connector with key on...see if you have the same .25 volts there also...maybe check some other sensors with a 5 volt ref. You can try ECT sensor by the #1 spark plug....and the AC sensor which is on the right side by the AC Schrader valve...it's forward of the high side Schrader valve and it's a 3 wire sensor...I believe the bottom of the 3 wires is the 5 volt ref, Don't be frustrated because even for a Pro this may take some time AND MONEY to figure out....have you disconnected both "Star Connectors" bus bars or "combs" I had pictured and jumpered the wires between the dark and light green wires ??...and like I had said if this all started after your tune and if the PCM was removed you'll have to get down there and start checking...good luck bro !!! ....this picture shows the Star Connectors jumpered !!
Yeah, I already did the star connector procedure to no avail. Also, I got 5 volts at the throttle sensor. I guess I'm just going to have to crawl down there and check the PCM wiring.
OK, but if you can check a few others that would be great....and like i said I don't know if there are 1 or 2 separate 5 volt regulators inside the PCM...maybe someone who knows may chime in !!...here is a video on checking a PCM and it's 2 parts...and even for Paul Danner in this video who is the "Diagnostic Master"
it's not a 5 minute job !!....AND CHECK THOSE PCM PINS !!
OK, but if you can check a few others that would be great....and like i said I don't know if there are 1 or 2 separate 5 volt regulators inside the PCM...maybe someone who knows may chime in !!...here is a video on checking a PCM and it's 2 parts...and even for Paul Danner in this video who is the "Diagnostic Master"
it's not a 5 minute job !!....AND CHECK THOSE PCM PINS !!
Another thing I may have failed to mention is see if the Tach appears to move while cranking...you can also pull a plug wire off and hold it near the coil pack...now see if you are getting spark....if NOT now pull a fuel injector connector off....first with key ON see if you have 12 volts on the pink wire...if you have a 12 volt test light now connect it to battery POSTIVE...while cranking touch the tip of the test light to the other injector wire (striped wire)...the test light should faintly blink...I just want to see if you are getting a crank signal...also,maybe clear all those codes and see what may come back...I think I may have information overloaded you so I think I'll hang back !!
