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IAT sensor and Wideband


Sonac
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I have a couple of questions which i'm hoping someone can help me with.

Currently, I have the notorious Innovate Motorsport wideband which eats sensors. Its currently connected to the ECU though a VOLT input on the expansion loom with a single wire. I am planning to replace it with a better AEM model which has faster polling and a two wire analogue output. If I am to assume correctly, the negative analogue wire will just connect to the green 'GND' wire of the expansion loom? Then I just load the AEM calibration table and it should be sorted.

My second question is about an Intake Air Temp sensor i'm about to install. Its a Bosch one so good quality. I have heard that all the LINK inputs have built in pull-up resistors. So am I to assume i'll connect the IAT sensor between the +5V and a VOLT input?

My expansion loom doesn't have any AN Temp inputs so i'll have to make do I guess.

Thanks

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What you have in mind for the connection of wideband O2 seems correct --- but I also recommend getting a CAN bus wideband controller (Link CAN Lambda, 14Point7 Spartan 3, or others above mentioned by Confused).

For the IAT, it should be An Temp input & Gnd (sensor). If you'd be using a free An volt input instead for temp, you'd be having to connect a 1k-Ohm pull-up resistor.

image.png.cf8a996e9941bb402935ada469cd5015.png

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Thanks for the help all.

I actually bought a X-Series AEM gauge so I guess it should be able to do CAN as suggested. I will have to try and figure that out.

And I appreciate the circuit diagram for using the voltage input for the temp sensor. That will be the way I do it then. I have some resistors somewhere. I didn't replace the airbox sensor input because I think it will be useful to have both.

 

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2 hours ago, Sonac said:

I didn't replace the airbox sensor input because I think it will be useful to have both.

The air box temp is not useful for anything related to running the engine.  

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Are you installing this on a 3rd generation 3SGTE engine?  If so, there is an intake manifold air temp sensor screwed into the intake plenum (M16 thread) that you could potentially run a reducer fitting to put the temp sensor in there and repurpose the wiring to (with a change in connector) and it's already wired to the Temp 3 input on the ecu.

Edited by koracing
corrected input callout (Temp 3 instead of Temp 2) for factory manifold air temp sensor
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On 6/29/2022 at 3:45 PM, koracing said:

Are you installing this on a 3rd generation 3SGTE engine?  If so, there is an intake manifold air temp sensor screwed into the intake plenum (M16 thread) that you could potentially run a reducer fitting to put the temp sensor in there and repurpose the wiring to (with a change in connector) and it's already wired to the Temp 2 input on the ecu.

I thought there was. But when I took it to the tuner last, he said there was no other temp sensors connected to the ECU. I had the welder put threads into my new intake pipe just before the throttle body which should be a better place for this sensor anyway. Oh well!

On 6/29/2022 at 2:25 AM, Adamw said:

The air box temp is not useful for anything related to running the engine.  

Perhaps I'll use that input then since the wires are already in the engine bay.

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Is that the plenum temp sensor? Its screwed into the manifold above the fuel rail. Its the only sensor which goes into the intake system.

My tuner said the ECU could only see one sensor, the one on the intake cone.

I will have to plug my laptop in later and see if I can find it... and if so i'll chop the wires and splice in my new sensor which is in a much better location.

Screenshot 2022-06-30 182308.png

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I plugged my laptop in to investigate further.

I went into the link software and opened the runtime values.

AN Temp 1 is ECT and is reading 1.12v

AN Temp 2 says IAT and is reading 3.57v

AN Temp 3 has no label but it reading 3.07v
AN Temp 4 reads almost 5v so open circuit

I disconnected the sensor which would go into the factory air box. AN Temp 2 showed fault and the voltage went to 5v.

I disconnected the brown sensor I took a picture of on the intake plenum. What'd ya know! AN Temp 3 went to 5v.

So it IS connected to the ECU. That makes wiring so much easier!

 

Tomorrow I will chop the plug off, and splice in my nice Bosch IAT sensor which is located just before my throttle body so won't heatsoak unlike the stock position.

 

Thanks again for the help.... now I just have to figure out the CAN connection for the wideband.

 

Screenshot 2022-06-30 200613.png

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  • 4 weeks later...

Yeah sorry for the late response, but it IS connected to the ecu yes as you discovered.  It is mildly troubling your tuner did not make these same determinations that you did.

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