IAT sensor question

[Calan]

Just picked up an IAT sensor: GM/Delphi #25036751 - recommended on DSMLink's list of sensors (pic below).

Couple of questions:

1. Where is the best place to mount this? I would rather not have to pull the intake mani if possible. (And why does it have a big-#ss 3/8 NPT thread? I've got my water/meth injection nozzle just in front of the TB elbow, if it matters. I would guess I want this sensor after the injection?

2. Where can I find a connector for it, or which pin is which so I can solder/epoxy my own.

3. Is there a tap in the engine compartment harness that I can wire it into, instead of running wires and splicing into the ECU? (I have a GM MAF and MAF-T and IAT/Baro are bypassed in the chip).

TIA

You must be logged in to view this image or video.

 

[turbosax2]

1. In the throttle body elbow - about 3-5" from the throttle body. It is good that your water/meth injection nozzle is right before the throttle body. Place the iat sensor farther away from the throttle body than your nozzle. Give it a few inches in between them at least - you don't want to spray water/meth on the sensor.

The bung is huge on these things! The torque spec. is 25 ft.lbs. for the AEM iat (identical to the GM iat).

2. Home » Shop » Connectors » Delphi / Packard » Connector Kits » GM Delphi / Packard - IAT / MAT / ACT Sensor Connector Kit
One wire gets grounded and one goes to the ecu. It doesn't matter which wire goes where. I would use the IAT Input (ECU Pin 8) since you are using a GM maf.

3. You can probably tap into one of the wires that went to the maf. I'm not familiar with 1g's, but on 2g's the stock iat sensor is part of the maf. I would assume that one wire is dedicated for this and runs to the ecu. You could check for continuity between the wire at pin 8 on the ecu and find the wire it corresponds to on the maf connector.

 

[gixrman]

I used the stock IAT wire cut it from the harness and extended it to the sensor. the other wire goes to ground. DO NOT mount it on the intake, I tried this already and it acts as a heat sink. I mounted it about 6inch's from the TB and the temps vary and respounce is good.

 

[gixrman]

I used the stock IAT wire cut it from the harness and extended it to the sensor. the other wire goes to ground. DO NOT mount it on the intake, I tried this already and it acts as a heat sink. I mounted it about 6inch's from the TB and the temps vary and respounce is good.

oh yeah after just go into link and hit the ignore IAT/ baro and then rename it under ECU values.

 

[Calan]

Hmmm... so you're saying mount it in the UICP before the WAI nozzle? I was thinking you'd want it after that, so you'd see the affects of the water cooling... but it would definitely be easier if I mount it between the nozzle and the MAS

 

[Calan]

I used the stock IAT wire cut it from the harness and extended it to the sensor. the other wire goes to ground.

Did you use sensor ground or chassis ground?

 

[turbosax2]

Hmmm... so you're saying mount it in the UICP before the WAI nozzle? I was thinking you'd want it after that, so you'd see the affects of the water cooling... but it would definitely be easier if I mount it between the nozzle and the MAS

I did a bunch of searching on this a few months back. There really isn't a whole lot of information out there, but the general consensus I found was to put the nozzle between the iat sensor and the throttle body. Just using common sense (which could be completely wrong in this case), I don't think that spraying water/meth on the iat sensor can be good for it. I also think that seeing pre-injection temperatures would be more beneficial to you.

 

[gixrman]

I used chassis ground. I also have mine before the W/I nozzles and have had no side effects on the sensor.

 

[gixrman]

Shit, let me rephrase that, its located after the nozzles. I get what your saying Eric I want to know what temps the W/I is lowering it to seeing as thats what the motor is seeing.

 

[Calan]

Just had a look at my car, and the sensor will have to go in front of the GM MAS, which sits right in front of the TB elbow (well... 4 inches of coupler and then the mas).

 

[turbosax2]

Why can't you put the sensor on the throttle body elbow? This is where my brothers is at.

 

[Calan]

Shit, let me rephrase that, its located after the nozzles. I get what your saying Eric I want to know what temps the W/I is lowering it to seeing as thats what the motor is seeing.

That's what I was thinking.. but the more I think about it, it doesn't seem like that would be very accurate anyway, since the water hasn't fully dispersed into the air stream and had a chance to absorb much heat... being that close to the nozzle.

Besides that, if the injection stream is actually hitting the sensor, it wouldn't be seeing the actual "air" temperature.

Hmmmmm...

Do you see a noticable difference in IAT's between injecting and not injecting?

 

[Calan]

Why can't you put the sensor on the throttle body elbow? This is where my brothers is at.

That's about where my WAI nozzle is

 

[turbosax2]

What about moving your nozzle closer to the tb and putting the sensor where it used to be?

 

[Calan]

The WAI seems to work pretty well... don't wanna fix it if it isn't broke

And there isn't a whole lot of room there... it would still be placing the sensor really close to the nozzle

Here's a pic... you can see the nozzle in the TB elbow just below the cruise cables. (The UICP is hard; it's just wrapped in front of the MAS)

You must be logged in to view this image or video.

 

[gixrman]

That's what I was thinking.. but the more I think about it, it doesn't seem like that would be very accurate anyway, since the water hasn't fully dispersed into the air stream and had a chance to absorb much heat... being that close to the nozzle.

Besides that, if the injection stream is actually hitting the sensor, it wouldn't be seeing the actual "air" temperature.

Hmmmmm...

Do you see a noticable difference in IAT's between injecting and not injecting?

Funny you ask since I just got this setup running last week. I run a two stage W/I setup with the first coming on at 9psi(about 24" from TB and the second at 15psi(about 8" from TB). I have not seen a difference in IAT(6" from TB) with it on or off but knock disapears and i'm running 25psi with it. I still have some things to work out like my W/I pump is leaking and i'm using the 60psi shurflo pump thats 3yrs old and I think its dying. With the first nozzle coming on at 9psi I should see some change in temp since its so far away from the IAT. I have a theory that the low pump pressure is causing the spray to not be as effective. I ordered a 150psi switch from devils own which will be here next week and we'll see if that fix's it.