MAP sensor wiring help PLEASE!

[lemoose]

To the people having the warm start idle issues, where are you running the MAP sensor? I have mine on the brake vacuum line and ive noticed that if i hold the brake after a warm starting the idle settles. I think the relationship is clear but the mechanism of action not so much to me. Would running the sensor on the air rail instead possible resolve the idle issue?

[davidinnyc]

I just recently installed a Karbonius airbox and used the following:

1. CSL air rail
2. Kassel MAP wiring kit (COVID-19 kit would do the same thing, just need to terminate on your own)
3. Turner IAT harness (version with IAT and MAF plug only, no third dongle)
4. MSS54HP CSL DME from Kassel

I ran the MAP wiring as follows:

1. Yellow to Pin 18
2. Brown/Orange to Pin 16
3. Red/Green to t-tap Pin 7 (not thrilled about the t-tap)

IAT harness plugged straight into the MAF connection. No issues at all with drivability or weird frequencies using Pin 16.

Hardest part of the entire process was pulling the old DME out of the car (thing was really sandwiched in the plastic carrier) and pulling the MAP wiring through the rubber grommet/tubing running through the rear of the DME box.

David

[Philom5]

Hey !!.., thx for posting. I guess this thread is pretty dam old but deals with my problem perfectly.. .

I'm not running the Turner harness, I used the Kassel CSL conversion kit. They update the ECU and ship it back with a Bosch MAP sensor, IAT sensor and wiring harnesses you wire to the OE harness. I ran mine back to the E28 glove box which is where my ECU lives unlike the E46 chassis. Not a big deal..

So today I was messing around with Testo and looked at a few more data points.

MAP voltage key on - 3.5V
MAP Pressure key on - 877 mbar
Atmospheric Pressure (at ECU) - key on - 1030 mbar

Here's some screen shots.., it's weird how all my values are low. I'm going to look for a local E46 M3 owner that I can pry with drinks and dinner to allow me to tap into their OBD port for some testing. As sort of an A-B test. As a next step though I'm going to check the ECU's main ground. Anyone know where it's located ?

Pic 1 - MAP Pressure Key On (via Testo) Vs the ECU's Environmental reading.
Pic 2 - MAP voltage and Pressure at Idle.
Pic 3 - ECUWorX MAP Voltage pic (For Comparison).

To me everything coming out of my ECU is 20% low. And pic 1 showing what the MAP sensor is reading for atmospheric compared to the internal ECU sensor is baffling.


Thx.

[Cubieman]

Hi guys, boy has this thread been a great read. I swapped the S54 into my E28 M5 years ago and last year converted to the CSL tune. I run the Kassel MAP kit and it works perfectly. But recently I developed a lean idle condition and also lean at cruise. I'm hitting 17s to 18s at idle and cruise in the high 16s. I have an external wideband installed for AFR monitoring by the way.

So in reading this thread I see that many have used pin 17 for ground rather than pin 16. I'm using pin 16 because it was cleaner, the Kassel kit comes with the connector and you just push it in. But now that I have this lean condition I'm questioning the wiring setup. Datalogging using Testo I'm getting MAP voltage of 3.5V with key on, position 2. MAP pressure is also low, 820 mbar and I'm at sea level. It should be 1000 according to the ECUWorx site. I tested the power and signal voltage in and out of the MAP sensor and get 5V into the sensor from the ECU and 4.1 out of the MAP sensor, signal wire. Pretty normal from what others have posted.

While data logging I looked at the MAF chart and it shows identical reading to the MAP sensor voltage. The MAF plug isn't connected so how in the hell is Testo reading a signal ? Does the CSL firmware use the same MAF circuitry for the MAP sensor ?

Anyway, I'm going to swap grounds and see if it makes a difference. Will post with my findings. Any thoughts please chime in.

Also note, my lean condition flipped one day with no changes to the system. This is the odd part.

Thx.

It's been so long I've forgotten which all wires the MAF uses, I know pin 17 is MAF ground. You may be using some of the MAF wires for IAT or MAP so Maybe that's why you see a reading.

Are you running an Turner IAT harness or is it spliced into the MAF connector or what?

I too have a concerning lean condition, in my 6 years of ownership my first CEL was for "Bank 2 too lean", fortunately I have a WB O2 in that bank.
Last week when I was datalogging just crusing around say 3rd gear 3k while accelerating its damn near around a 15afr wise.

Anytime I really get on it that AFR rises rapidly, it supposedly hit 22 which is scary, I sure hope that is a mistake.
At least it's winter and I won't be driving it much until this is figured out, probably send some logs to the tuner to see what's what.

[Philom5]

Hi guys, boy has this thread been a great read. I swapped the S54 into my E28 M5 years ago and last year converted to the CSL tune. I run the Kassel MAP kit and it works perfectly. But recently I developed a lean idle condition and also lean at cruise. I'm hitting 17s to 18s at idle and cruise in the high 16s. I have an external wideband installed for AFR monitoring by the way.

So in reading this thread I see that many have used pin 17 for ground rather than pin 16. I'm using pin 16 because it was cleaner, the Kassel kit comes with the connector and you just push it in. But now that I have this lean condition I'm questioning the wiring setup. Datalogging using Testo I'm getting MAP voltage of 3.5V with key on, position 2. MAP pressure is also low, 820 mbar and I'm at sea level. It should be 1000 according to the ECUWorx site. I tested the power and signal voltage in and out of the MAP sensor and get 5V into the sensor from the ECU and 4.1 out of the MAP sensor, signal wire. Pretty normal from what others have posted.

While data logging I looked at the MAF chart and it shows identical reading to the MAP sensor voltage. The MAF plug isn't connected so how in the hell is Testo reading a signal ? Does the CSL firmware use the same MAF circuitry for the MAP sensor ?

Anyway, I'm going to swap grounds and see if it makes a difference. Will post with my findings. Any thoughts please chime in.

Also note, my lean condition flipped one day with no changes to the system. This is the odd part.

Thx.

[AWE46M3]

Essentially just bypassed the adapter to the MAF harness and wired the IAT directly to the DME pins. Honestly if I had known when I got my airbox, I would have just made my own IAT harness for less and ended up with the same result but less headaches to get to this same point. It's literally two pins and you don't have to modify the factory harness at all. Aka easier to revert back to stock if ever needed.

Turner sells a IAT relocation kit that is marketed for Alpha N that does not have the extra MAF plug in case anyone is looking for that.

[sapote]

The noisy or pulsing voltage: does the pulsing or oscillation signal affect the engine running? The graphs were plotted by the data recorder which got the data from the DME(after signal preconditioned and filtered before A/D converter and maybe some software digital filter in the code)? It's hard to think this noisy data doesn't affect the engine unless the DME doesn't use it or only a small percent of it. Have anyone measured the signal voltage with a scope to confirm it has the same noise as the graphs above?
To check if the DME use this signal: remove the signal wire (pin18) off the sensor and manually changing the voltage from 1.5v (idling) to 4v (WOT) -- one can use a variable resistor POT with one end to sensor GND and the other end to sensor 5v -- with the engine idling and running at 3000rpm, and see what is the effect.

[Thoglan]

Hey, what’s the solution? Both my pin 16 and 18 are occupied

Splice into them

[Svicker]

Hey, what’s the solution? Both my pin 16 and 18 are occupied

[BMWfanz]

Got it, BMWfanz, your selection of mss54 serial is correct, I'll see if I can't load up testo and tell you how to get to where you need to be.

Is the 2nd photo yours? If so the status_vanos_1 is it I do believe. Sorry for the confusion.

Will try to make a video, maybe I do something wrong with laptop settings

[BMWfanz]

I guess I'm a confused as to what you are trying to do with testo, you stated you wanted to check your MAP sensor, in your first picture you can clearly see both MAP mbar and MAP v values being read out.

Also, you have the vanos tab open as well in your first photo. You just need to click on the little boxes to the left of "MAP mbar" and "MAP v" to see the values..

First screen is what I need- second is what I have in my Testo.

[Cubieman]

Got it, BMWfanz, your selection of mss54 serial is correct, I'll see if I can't load up testo and tell you how to get to where you need to be.

Is the 2nd photo yours? If so the status_vanos_1 is it I do believe. Sorry for the confusion.

[COVID-19]

I guess I'm a confused as to what you are trying to do with testo, you stated you wanted to check your MAP sensor, in your first picture you can clearly see both MAP mbar and MAP v values being read out.

Also, you have the vanos tab open as well in your first photo. You just need to click on the little boxes to the left of "MAP mbar" and "MAP v" to see the values..

Disregard the first picture, his is only the second pic. First pic was for reference. I’m not in the country to check my laptop and or file.

[Cubieman]

Mine looks like this, no Vanos bookmark

I guess I'm a confused as to what you are trying to do with testo, you stated you wanted to check your MAP sensor, in your first picture you can clearly see both MAP mbar and MAP v values being read out.

Also, you have the vanos tab open as well in your first photo. You just need to click on the little boxes to the left of "MAP mbar" and "MAP v" to see the values..

[BMWfanz]

So when you click "MAP preasure" over on the left it's doesn't graph or what? It looks like it's producing some kind of reading in your pic.
"MAP mbar = 1006"
"MAP V = 4.1"

Looks like your seeing MAP readings no?

Mine looks like this, no Vanos bookmark