Procharged LT4 Help!!!
12-22-2012, 05:17 AM
#21
12-23-2012, 05:43 PM
#22
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Without any further information, I agree with MasterTomos.
Judging that you're getting a P0100 and not a P0103, I'd venture this is NOT a maxed-out MAF problem (i.e., unrelated to the MAF massager/forced induction). Sounds like you just have a physical problem with the MAF circuit -- either the wiring, electrical connector, and/or the sensor itself. I'll assume you do not have any form of datalogging/scanning software to verify the MAF g/sec output readings, but you should perhaps look into getting something of the sort. It helps out a lot.
Digging through your post history at the corvette site, it appears that the MAF code predated your forced induction install? I found the thread where you had two similar connectors and weren't sure which was for the MAF. If you're not certain, then go buy yourself a multimeter with continuity check (if you don't already own one), and trace the wires back to the PCM pinouts. This will also verify that there are no faults in the wiring.
Assuming the Y-body OBD2 PCMs are similar to the F-body OBD2 PCMs, then you need to probe the MAF Yellow Wire -- > Pin 19 on the Black PCM connector. If you instead get continuity to Pin 1 on the RED connector, then that's actually the crank sensor pigtail. (I don't even remember what the AIR pump connector looked like, but I believe it was similar in appearance.) You can also test this yellow wire for +5 VDC with the ignition key in the 'on' position (not run), MAF disconnected.
You should be able to probe the two remaining wires for power/ground (+12 VDC). I'm not entirely certain where they lead, but likely Pin 16 for ground and either Pin 28 or 29 for the power wire on the BLACK PCM connector. Make sure the power wire isn't shorted to ground. Also inspect the female terminals within the electrical connector itself -- sometimes the little terminals snap off and prevent connectivity when plugged in (in which case, the pigtail needs replaced).
If all the wiring checks out, then I'd suspect the MAF sensor itself. Perhaps swap with a buddy if you know of any other local 'vette owners, reset the PCM, and see if the MAF code comes back.
Stay off the throttle until you get this figured out.
Judging that you're getting a P0100 and not a P0103, I'd venture this is NOT a maxed-out MAF problem (i.e., unrelated to the MAF massager/forced induction). Sounds like you just have a physical problem with the MAF circuit -- either the wiring, electrical connector, and/or the sensor itself. I'll assume you do not have any form of datalogging/scanning software to verify the MAF g/sec output readings, but you should perhaps look into getting something of the sort. It helps out a lot.
Digging through your post history at the corvette site, it appears that the MAF code predated your forced induction install? I found the thread where you had two similar connectors and weren't sure which was for the MAF. If you're not certain, then go buy yourself a multimeter with continuity check (if you don't already own one), and trace the wires back to the PCM pinouts. This will also verify that there are no faults in the wiring.
Assuming the Y-body OBD2 PCMs are similar to the F-body OBD2 PCMs, then you need to probe the MAF Yellow Wire -- > Pin 19 on the Black PCM connector. If you instead get continuity to Pin 1 on the RED connector, then that's actually the crank sensor pigtail. (I don't even remember what the AIR pump connector looked like, but I believe it was similar in appearance.) You can also test this yellow wire for +5 VDC with the ignition key in the 'on' position (not run), MAF disconnected.
You should be able to probe the two remaining wires for power/ground (+12 VDC). I'm not entirely certain where they lead, but likely Pin 16 for ground and either Pin 28 or 29 for the power wire on the BLACK PCM connector. Make sure the power wire isn't shorted to ground. Also inspect the female terminals within the electrical connector itself -- sometimes the little terminals snap off and prevent connectivity when plugged in (in which case, the pigtail needs replaced).
If all the wiring checks out, then I'd suspect the MAF sensor itself. Perhaps swap with a buddy if you know of any other local 'vette owners, reset the PCM, and see if the MAF code comes back.
Stay off the throttle until you get this figured out.
