This is a long story; I apologise in advance. I hope this is a cautionary tale for anyone attempting to upgrade to a PRO-M unit for their 4.0 or 4.2 AJV8's and maybe, hopefully someone can point out if I've done something wrong here.

Placing the order
I have recently bought the 92mm MAF from PRO-M racing to complete my intake system for my STR. I went for this unit because some forum members seemed to have success with these units and primarily because I've read somewhere on here that PRO-M actually developed the calibrations using OEM AJ27 and AJ34 intakes of forum members. I placed the order using the instructions by AVOS from here; I also bought the upgrade for the 30-point calibration sheet (instead of 9 points) and the pigtail needed for wiring.

After placing the order and getting the confirmation that PRO-M started their work, I started aggregating information on the wiring to prepare for the install. I bought connectors, wiring, crimping tools, iat sensor etc. and starting digging into the electronic guides for the XKR and the STR. The wiring information (the wire colours) on here seems to be based on the XJ/XKR so I translated that to the STR wiring. PRO-M themselves don't really give you the pinouts of the MAF... so here is what I came up with.

Wiring schema
PRO-M; Function --- STR; Function
E <not used>
A; 12V --- Green/Blue wire on MAF connector; Switched 12V power
B; GND --- Black/Pink wire on MAF connector; Signal ground
C; GND --- Back/Pink wire on MAF connector; Signal ground
D; SIGNAL 0-5V --- Green/White wire on MAF connector; Input signal 0-5V
F <not used>

IAT #2 Sensor --- STR
1 12V --- Blue wire on MAF connector; Switched 12V power
2 GND --- Black/green wire on MAF connector; Ground
I have combined B and C to the black/pink wire; as AVOS has posted before; except on that schema to wire colour is black/white which corresponds to the XKR/XJ wiring diagrams, in the STR it is black/pink

I'm pretty sure the wiring is correct; I'll come back to that later.

Arrival
When the package arrived, which was after only a couple since placing the order, I hooked up the wiring, ziptied the IAT sensor to the filter and double checked the wiring - twice! Don't want to fry such and expensive part that came from half-way across the world (I'm in europe). The MAF came with and invoice (with some sensitive info blacked out, or ripped of; which is odd but whatever...) and a very minimal looking calibartion sheet. I counted 20 datapoints on there, which is not the 30-points sheet they promised; It also looked wildly different from other sheets I've seen on this forum... but whatever right? I quickly installed the instake and to me, it looked glorious under the hood!



I hooked up my OBD scanner and monitored the MAF voltage, ground and measured g/s. I knew what to expect here since I've written it all down beforehand. With the ignition switched ON and the engine OFF I was looking for:
Ground: 0V
Voltage: 0.63V
Measured g/s: 0

On idle, transmission in P my car does 9-10 g/s because of the Kenne Bell and the bigger XKRowler throttlebody (which can't close the airflow enough to get to 7 g/s on idle).

First start
Okay, all set; I turned the key to ignition ON, not starting the car yet. And ... a warning pops up on the dash; restricted performance...
I checked the wires again, tried to OEM MAF; which still worked, so on the car side of things nothing is fried, yet. I tried agian with the PRO-M; same result, restricted performance.

The measured g/s was 0; which is good, the engine is OFF. The IAT sensor I've added to the wiring was measuring 17c; which was also correct compared to the OEM IAT sensor. Ground voltage was 0; good, no shorts in the ground wiring. So for it looks like the wiring is okay! The starting voltage read: 0.25V... Okay thats not even close to the OEM's voltage of 0.63V and this MAF is supposed to be scaled up not down right? So what gives? I checked the wiring AGAIN, no weird resistances or anything...
I knew at this point that the calibration was way off; This thing just became a $600 paperweight to me (that's what it costed me with tax and shipping, not even including import duties)

I compared my calibration sheet to the ones found on this forum from back when people were getting the R&D done with PRO-M. Starting voltage on those sheets (which include a lot more info) read around 0.8V
What is also weird is that my sheet goes upto 4.5V an then to 5V with nothing in between.

Here is a picture of my calibration sheet that was shipped with the unit:


And other sheets, from PRO-M found on this forum; which I expected to have been loaded on my unit:





You can clearly see that the name for the calibrations is the same: "03-06 JAG 4.2" and still the numbers are totally different...
This is where the story ends for now; I've yet to decide what to do next - I am about to send an email to PRO-M asking for help and to confirm the proper calibration file is loaded into my unit; which I doubt. Best outcome is that my wiring is off and I can fix this by repinning a connector. Second best would be if PRO-M can and would be willing to recalibrate the unit and send me a return label for shipping it back to them under warranty.

 

The lower sheet was provided by me, but this was a generic measurement (not from ProM) for a AJ27 4.0 XKR, not the 4.2, these are slightly different.

As mentioned via mail as well, the upper sheet (where I have no idea who provided that!), has to be treated careful as well. ProM could have made adjustments for different injectors, and I had an another variation where the mixture was made a little bit leaner top end which also lowered the threshold where the ECU would cut off (iirc that was around 4.85 or so voltage).

I have no ties with ProM, and the tune you have gotten doesn't seem to be correct as at zero flow you do need to have the higher base voltage (which they had in the past), I have installed a couple 4.2's), you should contact ProM over this, let them explain what has happened.