MAP sensor wiring help PLEASE!

[heinzboehmer]

I think what we are seeing is the vacuum pulses for the cylinder that the kassel adapter is installed over, the entire rail shares air but being right above a cylinder at idle would read just that one stronger than the rest right? When it’s on the booster hose or a factory rail you see much smaller pulses because it’s reading all six cylinders evenly. As soon as the throttle is opened it wouldn’t matter anymore. Or are people thinking it’s more of EM interference from the injectors? I don’t know that it matters as long as the car runs well.

That's what I was thinking too and is why I ran that last test trying to keep the engine at a set rpm. The readings seem to smooth out during rpm changes and oscillate at constant rpm. Not sure how this behaves at higher rpm/load, but it's clear that having the sensor positioned so close to a throttle body is interfering with the reading.

[heinzboehmer]

I'm trying to make sense of exactly what parts I need to cleanly wire the MAP sensor in (I am aiming to do this without making any changes to the factory wiring harness, so no soldering or tapping). Following NZ_M3's thread on cslregister he says:



The first p/n he gives seems to just be the head of the wiring shown (that plugs onto the MAP sensor itself). As for the second p/n, I can't seem to find a good photo of the actual part, is it the rest of what's shown (with the turquoise connector end)? If so, what's the part number for the piece that the turquoise connector end would plug into, which goes all the way to the DME pins? Seen in this photo connecting into the turquoise end: https://farm5.staticflickr.com/4448/...37c74904_c.jpg

Am I confused about how this works? TIA!

You won't be able to wire all of this in without making changes to the factory wiring unless you get your hands on a CSL engine harness. However, if you buy the Turner IAT relocation harness (https://www.ecstuning.com/b-turner-m...iABEgIbrfD_BwE), you can cut and splice your new sensors into that. You're still going to need to move some pins around on the ECU connector however.

The reason NZ_M3 used that turquoise connector is because he owns a CSL and was interfacing with the CSL harness (turquoise connector is female counterpart to the CSL MAP harness connector). Your harness will not have a connector for a MAP sensor. Since you're going to have to create your own wiring for the MAP sensor, you won't need this connector.

[ATB88]

You won't be able to wire all of this in without making changes to the factory wiring unless you get your hands on a CSL engine harness. However, if you buy the Turner IAT relocation harness (https://www.ecstuning.com/b-turner-m...iABEgIbrfD_BwE), you can cut and splice your new sensors into that. You're still going to need to move some pins around on the ECU connector however.

The reason NZ_M3 used that turquoise connector is because he owns a CSL and was interfacing with the CSL harness (turquoise connector is female counterpart to the CSL MAP harness connector). Your harness will not have a connector for a MAP sensor. Since you're going to have to create your own wiring for the MAP sensor, you won't need this connector.

Ahh got it! It's all making sense now -- Cubieman mentioned he was doing it without splicing into the factory wiring, and he had the Turner IAT relocation kit, which I'm also getting. It's all coming together now, hoping to install on tuesday if all the parts get here on time!

[Cubieman]

If you use the Turner IAT and use pin 16 for map ground the only wire you will tap into will be pin 7 for MAP power. This assumes you are NOT running the flap which you won't be. So don't sweat it man, use a T-tap or better yet solder it in.

[thegenius46m]

If you use the Turner IAT and use pin 16 for map ground the only wire you will tap into will be pin 7 for MAP power. This assumes you are NOT running the flap which you won't be. So don't sweat it man, use a T-tap or better yet solder it in.

This is what I did. IAT was done with the turner harness and I removed the extra pins so the only two being used are from the IAT sensor and those convert into the maf connector using only the respective dme pins. Basically a direct connection to the dme but without having to hack the maf harness for easy reversion.

FYI the wires should be black and red only. I had to hack a spare terminal because one of them broke upon removal if you're trying replicate this based on color.

Initial Turner harness



Unnecessary terminals removed:



Also removed:



Done: (Should be red and black only. FYI: I broke the black terminal and had to crimp on the yellow connector if anyone needs this for reference)

[thegenius46m]

Also has anyone confirmed the voltage discrepancy between the ecuworx doc and what others are posting here? I have confirmed my wiring is correct but I only get 4v at ACC where ecuworx claims it should be 5v. My friend's car gets the exact numbers but he has a gm map sensor. Looks like the bosch sensor only outputs 4.xx V from what I saw on m3cutters and another csl guide? My car seems to drive fine but after this thread I want everything 100% lol

[terra]

Also has anyone confirmed the voltage discrepancy between the ecuworx doc and what others are posting here? I have confirmed my wiring is correct but I only get 4v at ACC where ecuworx claims it should be 5v. My friend's car gets the exact numbers but he has a gm map sensor. Looks like the bosch sensor only outputs 4.xx V from what I saw on m3cutters and another csl guide? My car seems to drive fine but after this thread I want everything 100% lol

The voltage will depend on the sensor. What’s important is that the pressure reading with the engine off is about equal to atmospheric pressure.

[NZ_M3]

Also has anyone confirmed the voltage discrepancy between the ecuworx doc and what others are posting here? I have confirmed my wiring is correct but I only get 4v at ACC where ecuworx claims it should be 5v. My friend's car gets the exact numbers but he has a gm map sensor. Looks like the bosch sensor only outputs 4.xx V from what I saw on m3cutters and another csl guide? My car seems to drive fine but after this thread I want everything 100% lol

the GM sensor has a different voltage scaling hence why it is different to the Bosch one.

what you need to do is ensure that the sensor reads atmospheric when engine is off and the number corresponds with the onboard map sensor in the dme itself - it should be virtually identical.

I’ll post up a reading from the CSL later but I have data logged this sensor despite it showing identical specs as the original and they are the same.

[NZ_M3]

This is off a CSL

[thegenius46m]

Good to know! Confirms my other theory about the sensor based voltage. Thanks guys. Can put this to bed now that I know my wiring was done right all this time haha. Just need to find some nice hose clamps so I can relocate the Map sensor to the abs unit area.

[ATB88]

If you use the Turner IAT and use pin 16 for map ground the only wire you will tap into will be pin 7 for MAP power. This assumes you are NOT running the flap which you won't be. So don't sweat it man, use a T-tap or better yet solder it in.

Okay, so, I'm more or less comfortable tapping into the DME wires (pin 7 and 17) for the MAP sensor, and will probably just do that, nbd. But supposing I really didn't want to touch any of the original wiring, and instead wanted to make all of my splices to the Turner IAT harness I would:

1. Tap the map ground wire into the IAT ground wire itself (which goes to pin 17 in the end anyway)
2. Connect the MAP signal wire to the unused pin 18 on the DME itself.
3. Would need to find a wire on the Turner IAT harness that is getting the same +5V power as the pin 7 wire. Is there such a wire on the Turner IAT harness?

[Cubieman]

Okay, so, I'm more or less comfortable tapping into the DME wires (pin 7 and 17) for the MAP sensor, and will probably just do that, nbd. But supposing I really didn't want to touch any of the original wiring, and instead wanted to make all of my splices to the Turner IAT harness I would:

1. Tap the map ground wire into the IAT ground wire itself (which goes to pin 17 in the end anyway)
2. Connect the MAP signal wire to the unused pin 18 on the DME itself.
3. Would need to find a wire on the Turner IAT harness that is getting the same +5V power as the pin 7 wire. Is there such a wire on the Turner IAT harness?

There is a power wire on the Turner Harness as it provides power to the IAT, use a multimeter to confirm where it is. What I don't know is if it is OK to use that same wire to power both your IAT and MAP sensors. I can't see why it would be an issue but I don't know.
As far as ground goes you can either use pin 16 (unoccupied) or pin 17. As you have probably read in this thread JBfrancis had problems when using pin 16 as a ground for his IAT. But Terra is using pin 16 for his IAT and I am using pin 16 for my MAP ground with no Ill effects so far.
Pin 18 will need to go to the DME as you stated, no way around that.
I found the rear most grommet going into the DME had a lot of extra space around the wiring bundle for me to pull my wiring through.

[cozmo kraemer]

How do you guys thread the wires through the stock BMW corrugated tubing? I have a heck of a time getting it through.

[heinzboehmer]

How do you guys thread the wires through the stock BMW corrugated tubing? I have a heck of a time getting it through.

I used an unbent hanger (and a ton of patience).

[dl.m3]

Does anybody have the part number for the pin terminals you insert into the X60003 DME harness? Realoem has a bunch which all look the same. Lol

I don't know if my parts guy will understand what Im talking about otherwise