With the maf sensor unplugged it runs fine idles where its supposed to revs fine runs smooth
Hi GhostedByNyx,
What this action is telling you is that when the MAF sensor is plugged into the MAF wiring harness at the CAI, the ECU is failing the MAF sensor due to its KOEO measured output is way off from what it should be during the KOEO ECU system checks (either the 12v ref voltage is off that heats the hot wire, the 5v ref voltage is off that the MAF sensor will be using to send the ECU the signal return voltage off the hot wire output against the airmass that comes into contact w\ it) thus the ECU is not allowing the engine to start. When you unplug the MAF sensor then try to start the car, the ECU sees that there is no MAF return signal coming from the MAF sensor, so the ECU will again fail the MAF then use the LWFM airmass table map the ECU is using w\ Ford's vers of SD (speed density) to calc airmass to operate the engine, thus the engine will start\run just fine as long as the MAF is unplugged. With the MAF sensor unplugged & engine running, if you check the ECU live data & see the STFT+LTFT start correcting back to normal from the lean condition the P0171\P0174 DTC's are flagging.....this is verification that the MAF sensor is the issue.
You, sure that you don't have a DTC for the MAF sensor? It could still be a pending DTC (ECU flagged it but hasn't yet failed it outright to then set a permanent DTC) so you might want to check for this....................
Your issue is centered around either 1.) the MAF sensor itself, 2.) MAF sensor connector (these do go bad) and\or wiring between the MAF sensor & the ECU (all 12v+ ref power & 5v+ ref power & all MAF sensor - grounds that the MAF uses is sent directly from\to the ECU) or 3.) the ECU +- connector pinouts that run\control the MAF sensor.
1st off, these SO ECUs are very finicky\hit or miss when it comes to using an aftermarket MAF sensor.........usually they work best w\ the OEM Ford MotorCraft ALM-131 MAF sensor.......but these are fairly costly (around $300.00 give or take at a typical Ford dealership) so if in a pinch IMHO I'd go to the wrecking yard & get a used OEM Ford ALM-131 MAF sensor as these are fairly robust & very rarely fail so you can save a few bucks doing this. Question....is the MAF sensor you bought at AZ an OEM Ford MC ALM-131 MAF sensor? If not, then it may be suspect.
But before you go this route, I'd check the MAF sensor connector to make sure that the connector isn't causing loose connections to the MAF sensor pins & that you have the proper 12v+ ref voltage & the proper 5V ref voltage at the connector & check both grounds to ensure that they're good & all wiring has low olms (low resistance) between the MAF connector & ECU engine harness connector (believe the middle connector at the ECU), then check the MAF sensor itself for trash across the hot wire.......if MAF sensor is clean & the wiring\connector checks out then replace the MAF sensor. The ECU is most likely OK..........but you'd need to verify that all this other stuff is good before moving to condemn an ECU anyway.
From reading the rest of your postings, this is also indicating to me that your issue may be getting learned by the ECU over time......say a vacuum leak\clogged injectors that is causing these lean issues & the ECU isn't\can't make the necessary MAF corrections to the LWFM airmass map (MAF Adaption is turned off in the tune.....are you using an OEM tune calibration or has this ECU been tuned) so the ECU is adding more & more fuel to try to correct the lean condition until it can't anymore then it sets the P0171\P0174 DTC's (P0171 is B1 system lean, P0174 is B2 system lean) which says that this issue is common between the 2 banks......which again is directly pointing to the MAF sensor (your unplugging the MAF causes the engine to start\run is a tattle tale).
Hope this helps you out........
PS edit--Forgot to add this..........another couple tests to run is to disconnect the battery for about 5-10 minutes to reset the KAM in ECU & put the ECU in learning mode, then try to start car w\ MAF sensor plugged in & see if it now starts up & runs........if it starts & runs now w\ MAF plugged in, this is indicating that your MAF issue is a learned issue that is being caused from something else. Also, just before you start the car after KAM reset, if you have a general OBDII scan tool that can show live data put car in KOEO, hook up scan tool & pull up live data & see what is being reported for MAF lbs\min or gms\sec output from MAF sensor to ECU.........if you see any numbers other than 0.00 (should be this when no airmass is moving by the hot wire), whether + or - numbers, then the MAF sensor 5v+ return signal is showing to be bad (usually the MAF sensor itself is failing but also can be a bad connection in MAF connector).
