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Car is a V3 STI running ESL and mafless.
This is my 2nd Impreza running ESL and I have to say the support that Andy from ESL gives is second to none! He is always happy and very quick to answer any questions I put to him. I'm putting this one up on the forum as I've seen a couple of threads regarding using an IAT sensor.
The sensor that's fitted is a JT Innovations one,now on my 1st log the the reading were a constant 22.5 degrees,the parameters have been changed to...gradient 8192 and offset 400.
Having a look through the manual it says to set the parameters to...gradient 16724 and offset 56(as a guide,fine tuning may be required)
I used these setting and the IAT log was a constant -20 degrees.
My question,is the sensors parameters just used as a look up table or should I be getting the true reading of the intake temps? Do I need to fit a gauge if I want to see the intake temps or can it be set up to give me these readings in the log data?
you should be able to get it to read correctly in the log data - once you find the right settings for it. As far as I can work out it's kinda of a sliding scale based on the sensor resistance range and the actual temperature range that it supports.
Did the sensor come with info on resistance or scale info? I've seen some sensor come with a chart showing what voltage/resistance is equal to what temperature.
Thanks bludgod,I will have a look online to see if I can find those settings for the sensor that's fitted,failing that I could just have a play to see if I can hit the correct scale.
Only had the car a week and it's pretty much as it was when I bought it,not really had much time to play with the map.
You were a great help to me on my last car and all was sweet until some tw@t decided to steal it
Did you get any updated software from Andy yet mate?
No pal,only just back in a Scooby a week so not had much time to look at my new setup/map. Don't think the new software with the injector duty is finished yet?
If the gradient is not zero and there is no change in output, then the ECU is seeing no change in voltage from the sensor, so it probably isn't connected properly, or the sensor is dead.
As with any linear sensor, if you have two reference points it is easy to set up. With a temp sender I use ambient from the met office and a glass of icy water which will be at 0 deg due to latent heat of melting.
The important thing to remember is to set the difference (gradient) first, and offset second. Same applies to any linear sensor (MAP is another common one).
Cheers Andy,I will have a look at the set up this week.
Only had the car a week so not had chance to look things over properly.
Temp sensor was fitted last month along with the twinscroll,previous owner said Duncan at race dynamix set it all up so I would think everything should be as it is,maybe a loose wire or something?
As you mention the map sensor,I'm getting a constant reading of 2054 barometric pressure in the logs but the baro look up table is a constant 1012,I'm assuming this is correct tho as I'm running a mafless set up.
Cheers
Rich
Check the voltage at the signal wire, sounds like it's earthed.
Yes, mafless assumes standard atmospheric baro press (should be 1013mbar, may be a rounding error, but close enough) as it can't afford to switch out to measure ambient any more as it is constantly measuring load, unlike MAF mode where it is just controlling boost.
Yeh 1013mbar is what it is,not got my laptop to hand so was thinking 1012 from memory lol.
Nice one Andy,I will check the signal wire 1st chance I get,hopeful that it's just a simple fix.
I've been trying to sort this out today,i'm certainly no electrician but since i've spent a bit of time on it so would be nice to fix.
Its got to be something simple as it's fairly straight forward in the ESL manual.
The sensor was recently fitted by someone who must of fit hundreds of these,so iv'e got to think its fitted correctly and don't want to tamper with it until i'm sure.
1st,,the IAT sensor is a JT innovation and has 2 wires,yellow and black(not sure which is which?)
The manual says one wire to 5v line on throttle pot and the other to temp sensor signal wire.
Then connect a 1K Ohm resistor from maf signal to maf ground.(all sound easy enough).
I will add some pics to help the story along..
This is how the 2 sensor wires are connected...
...
The gray 3 pin plug in the picture has nothing connected to it(i think this plug is for the maf?)
The 2 wires from the IAT sensor are connected to these 2 wires(not sure where these went when running maf? are these throttle pot and temp sensor signal wires?)
The yellow/brown wire to yellow sensor wire and white/brown to the black sensor wire. The meter reads the Yellow sensor wire as Earthed and no reading from the black.
i've looked under the bonnet and by the ECU but can't see a resistor wired in anywhere? the only things spliced into the ECU are the ALS switch which is working fine,and a black wire pictured below with some what looks like japan writing on the tape,this runs from pin block 135 no.3 which is vehicle speed sensor 2,this wire ran to the back of where the stereo sits and isn't plugged in to anything...
...
.
So am i just missing the 1K Ohm resistor from maf signal to maf ground? Or do i need to re wire?
The pic below is the (what i think is) the maf plug. 3 wires are,,,yellow/blue which reads 13.2v the black reads earth and no reading from green/black.
All meter readings were taken with ignition on but car not started.
Looks like it has been set up wrong by the "pro" mapper lol..
Maybe just slapped on to make the customer feel like he's not been shafted.
Anyway,waiting for a 1k Ohm resistor then I will wire it up as it should be.
maybe the customer fitted the sensor to shave 20p off the price of the remap though - hard to say how it's got where it is but at least your on the right track now!
13 September 2015, 11:40 AM
ESL mafless with IAT sensor Question?
