MAP sensor wiring help PLEASE!

[jbfrancis3]

Nuts! And no jumping around of IAT temp read-out?

Frank had his Snap-On diagnostic tool plugged into ODB port. We were watching refresh values of +122F, 33F, -10F, +132F....it went on and on. I had a spare IAT sensor plugged into the airbox (since I relocated the sensor) and using a different sensor, the same error readings occurred, so we ruled out the sensor.

I had to do a full check of wiring on the spot. I pulled up 0-06's post and checked all the wires; the only discrepancy was pin 16/17. I solded into 17 on the spot, we checked the diagnostic scan and boom, straight +68F.

At the risk of sounding uninformed (I am uninformed so hell with it), if you do a continuity check between 16 and 17, there is no continuity. I know that's probably due to circuitry limitations (total blackbox for me) but it doesn't help with peace of mind.

Sorry, I left out one other bit of detail in this write-up. Sharing for sake of transparency. I am using the same source for two grounds: 1) the IAT and 2) flap position sensor

Using pin 16 for IAT and flap position sensor: I got faulty IAT readings
Using pin 17 for IAT and flap position sensor: fixed my faulty IAT readings.

[Cubieman]

Thanks man, this is all great information.
Its unfortunate most of the good info is all gone.

[terra]

Nuts! And no jumping around of IAT temp read-out?

Frank had his Snap-On diagnostic tool plugged into ODB port. We were watching refresh values of +122F, 33F, -10F, +132F....it went on and on. I had a spare IAT sensor plugged into the airbox (since I relocated the sensor) and using a different sensor, the same error readings occurred, so we ruled out the sensor.

I had to do a full check of wiring on the spot. I pulled up 0-06's post and checked all the wires; the only discrepancy was pin 16/17. I solded into 17 on the spot, we checked the diagnostic scan and boom, straight +68F.

At the risk of sounding uninformed (I am uninformed so hell with it), if you do a continuity check between 16 and 17, there is no continuity. I know that's probably due to circuitry limitations (total blackbox for me) but it doesn't help with peace of mind.

You sure it wasn't continuous? Now I'm wondering what I did. I'm positive I used an extra ground for all the "new" equipment though.

[repoman89]

You sure it wasn't continuous? Now I'm wondering what I did. I'm positive I used an extra ground for all the "new" equipment though.

I could have sworn you tried it and later found it doesn’t consistently hold ground even though it appeared to at first. I read those damn wiring threads like 10 times before I figured out newtis

[Cubieman]

So it would seem pin 16 is in question. When I'm out there this week with it apart I'll see about the continuity.
I just hope unplugging pin 17 and re-plugging in with the MAP won't screw anything up.

[terra]

i just double checked my car, I'm definitely using pin 16 for my MAP sensor and IAT. Both I know read fine.

I do remember figuring out later on that the MSS54HP and non-HP are different in some regard with those pins. My car has a real HP.

[Cubieman]

i just double checked my car, I'm definitely using pin 16 for my MAP sensor and IAT. Both I know read fine.

I do remember figuring out later on that the MSS54HP and non-HP are different in some regard with those pins. My car has a real HP.

Awesome, good to know!

[duracellttu]

I purchased all the OEM wires to make sure the color codes match the OEM CSL setup. I have been running on this setup for a year without any issues.

NOTE: I have a 2005 ZCP, which has the MSS54HP from the factory. Kassel Performance did my CSP conversion for H-bridge and CSL software load.

There are three wires going to the MAP sensor:

1. Red/Green - Shared 5V --> spliced into from the existing reg/green wire, pin 7
2. Brown/Orange - Ground --> inserted into the 52 pin, grey connector, pin 17
3. Yellow - Signal --> inserted into the 52 pin, grey connector, pin 18

This link below is a great reference for those looking for CSL wiring information on a CSL clone. It shows how to wire both the MAP and IAT sensors.

https://www.ecuworx.co.uk/2016/03/01...csl-clone-ecu/

[Cubieman]

I purchased all the OEM wires to make sure the color codes match the OEM CSL setup. I have been running on this setup for a year without any issues.

NOTE: I have a 2005 ZCP, which has the MSS54HP from the factory. Kassel Performance did my CSP conversion for H-bridge and CSL software load.

There are three wires going to the MAP sensor:

1. Red/Green - Shared 5V --> spliced into from the existing reg/green wire, pin 7
2. Brown/Orange - Ground --> inserted into the 52 pin, grey connector, pin 17
3. Yellow - Signal --> inserted into the 52 pin, grey connector, pin 18

This link below is a great reference for those looking for CSL wiring information on a CSL clone. It shows how to wire both the MAP and IAT sensors.

https://www.ecuworx.co.uk/2016/03/01...csl-clone-ecu/

Thanks for that info, pin 17 is occupied, so I must assume you simply unplugged what was there and plugged in your brown/orange wire from your MAP.

Can you see unplugging pin 17 causing issues with use of the Turner IAT relocation harness? I guess what I am asking is does pin 17 run to (provide ground) to the MAF sensor?

Although after looking over wiring info for the IAT, it uses pins 22/25. So even if I unplugged pin 17 it shouldn't affect the Turner relocation harness as I have to assume the Turner harness simply splits off pins 22/25 wires from the MAF plug and directs them to the IAT connector on the harness.

Anyone know off hand what pin 17 provides ground to in a normal US Spec. M3?

[repoman89]

Thanks for that info, pin 17 is occupied, so I must assume you simply unplugged what was there and plugged in your brown/orange wire from your MAP.

Can you see unplugging pin 17 causing issues with use of the Turner IAT relocation harness? I guess what I am asking is does pin 17 run to (provide ground) to the MAF sensor?
If not, do you happen to know off hand what pin 17 provides ground to in a normal US Spec. M3?

https://www.newtis.info/tisv2/a/en/e46-m3-cou_200506/components-connectors/components/a-control-units-modules/a6000-control-unit-digital-motor-elecronics2/fX5GYo1

MAF sensor looks like

[duracellttu]

Thanks for that info, pin 17 is occupied, so I must assume you simply unplugged what was there and plugged in your brown/orange wire from your MAP.

Can you see unplugging pin 17 causing issues with use of the Turner IAT relocation harness? I guess what I am asking is does pin 17 run to (provide ground) to the MAF sensor?
If not, do you happen to know off hand what pin 17 provides ground to in a normal US Spec. M3?

Pin 17 is the MAF sensor on a non-CSL model car. You can unplug that wire and replace it with the MAP sensor wire OR just tap into it. It's really up to you...you might want to keep the wiring, if you ever consider removing the CSL airbox and going back to stock. If you plan to keep it forever, just remove the MAF sensor wiring all together.

Below are the wiring diagrams as a reference.

[jbfrancis3]

i just double checked my car, I'm definitely using pin 16 for my MAP sensor and IAT. Both I know read fine.

I do remember figuring out later on that the MSS54HP and non-HP are different in some regard with those pins. My car has a real HP.

Odd. I have an OEM HP as well. To which Kassel added the H bridge and loaded the CSL software (I wish TTFS had been able to do it, then the best would have been on it, but they have more critical things to do 😊)

Later this week, I will validate de-pinning 16 and switching to 17. And check continuity between the two pins.

It would be helpful if you could validate proper IAT readings at idle. And check continuity if you're up for it.

Then we can have two recent data points. Cubieman could also ask Jim when he speaks about any findings with pin 16. Because, you know, this is serious world-changing stuff.

[jbfrancis3]

One thing I learned in my little journey with wrong IAT readings is the concept of a signal ground, which is not the same as chassis ground on the vehicle. I have three questions for the group:

- Is signal ground effectively the chassis of the DME, which is then isolated from the chassis?

- Are there any other types or isolated grounds within the DME?

- Why in the mstewart wiring diagram in post #1 are there are unique +12v and unique grounds for each of the 3 sensors: MAP, flap position and IAT?

[Cubieman]

...this is serious world-changing stuff.

Hell yea it is!
I'll hopefully speak with Jim tomorrow or Tuesday. Just dropped a bunch of $ so I hope he will give me a few minutes. When I called a few months back he would talk at length which I very much appreciated because his time is definitely valuable.
Lately when I called for my DME I bought to have CSL software loaded and tuned it was like pulling teeth to get them to talk with me about any aspect of it. There were times if I wondered if the person on the other end of the phone was even listening to me at all.
After I sent my $960 I realized that I forgot to tell them I had a 6MT car, they didn't even ask if it was a SMG or Manual car and supposedly my DME was all set, but maybe they know that from the VIN?
I'm sure they have more important projects than sending a DME to some newb in Nebraska but it kind of unsettled me a bit the way the communication broke down in my last round of talks with Kassel. Hopefully that trend doesn't continue.

EDIT:
Not trying to pull this thread off topic especially after some great questions by JB but I just had to say that, sorry.

[COVID-19]

^Have heard similar things from other members too.