MAP sensor wiring help PLEASE!

[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]

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.

[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

[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.

[Cubieman]

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

[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]

I'd like to De-pin 17. I'll call Kassel tomorrow, but lately the person answering the phone hasn't been very helpful, I won't go further than that.
I have called in the past and talked with Jim and sure like to talk with him again for even a few minutes.

[jbfrancis3]

I’ve been using pin 16 for 6 years. It works fine.

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.

[jbfrancis3]

So the Kassel wire has two pins for the DME and one T tap. They say to wire it like a factory CSL MAP sensor.
One pin goes to 18
One pin goes to 17 (isn't this the factory CSL position?)
T tap allows splicing into wire from pin 7.

Where is Kassel thinking you should insert the ground pin if unplugging pin 17 is not an option?

I don't have any problems splicing but since I've got factory style terminations on this deal from Kassel I'd sure like to use them if possible.

You may be right here with the ability to de-pin 17. I said don't disconnect due to unknown function of that pin 17 ground on non-CSL applications but if you can confirm by asking someone like Jim, or terra here would probably know, that would be helpful to us all.

[Cubieman]

Don't disconnect the existing pin 17. Rather, split into the wire. Best to solder.

So the Kassel wire has two pins for the DME and one T tap. They say to wire it like a factory CSL MAP sensor.
One pin goes to 18
One pin goes to 17 (isn't this the factory CSL position?)
T tap allows splicing into wire from pin 7.

Where is Kassel thinking you should insert the ground pin if unplugging pin 17 is not an option?

I don't have any problems splicing but since I've got factory style terminations on this deal from Kassel I'd sure like to use them if possible.

[terra]

I’ve been using pin 16 for 6 years. It works fine.

[jbfrancis3]

Thats disconcerting to hear, would have been nice to just slot into an empty spot. I don't have any problems disconnecting pin 17 as long as it isn't a ground for something else I'm going to need.
But from the first wiring chart I posted that does not appear to be the case.

Empty slot was precisely why I started with 16. While on the dyno (at TTFS with Frank) I had to repin it to 17.

If anyone remembers on old M3F I was asking for help diagnosing a lean condition. I tested fuel system, some chimed in about the MAP sensor, etc. The faulty IAT reading is actually what caused it.

Once re-pinned to 17, the IAT readings were immediately corrected and the tuning was successfully completed.

Don't disconnect the existing pin 17. Rather, split into the wire. Best to solder.

[Cubieman]

DON'T use pin 16. Its not the same signal ground as 17. Using 16 caused erratic and false IAT readings on my vehicle.

Thats disconcerting to hear, would have been nice to just slot into an empty spot. I don't have any problems disconnecting pin 17 as long as it isn't a ground for something else I'm going to need.
But from the first wiring chart I posted that does not appear to be the case.

[jbfrancis3]

Use pin 16 or 17. Ground is ground. Pin 16 is undocumented IIRC, but if you check with a multimeter you'll find it's ground.

The Kassel pinout at the sensor end should be the same as the real CSL censor.

DON'T use pin 16. Its not the same signal ground as 17. Using 16 caused erratic and false IAT readings on my vehicle.

[Bigfoot]

Don’t be hard on yourself mate. If you are not familiar with circuit diagrams or automotive wiring it is quite sensible to be cautious.

After losing much of the information contained within M3forum it’s good to get some of the MAP sensor installation FAQs posted.

Do shout if you need more help.