Carberry IAT sensor
 

Hi all

couple of things....where the best location for IAT sensor, any particular type to buy, any info on how to wire them up pre-map?

Car is 03 wrx sti (with topmount)

Im sure i read using the factory maf as the IAT wasnt the best for readings etc
Happy to use stock maf if upto the job

Cheers

when keeping the top mount it's most commonly fitted there (close to the hose that goes to the throttle body
You will need drill and tap a thread to fit it, and hence clean all the metal swarf out after drilling. It's far easier to remove the inter cooler rather than the inlet manifold which is about the only other place you would want to fit it.
The general concensus is the o.e GM unit isn't the best, but is adaquate, I know a few have relocated it, but it involves fitting/glueing it in some sort of threaded boss to do that.
Most use an aftermarket unit. Any mapper that maps carberry generally keep them on stock.
But I've heard good reports about the Megasquirt one.

Here. (Bottom of page)
http://www.megasquirtuk.co.uk/msacc.html

yup - GM one will do rightly and they aren't big money:
http://www.efi-parts.co.uk/index.php?productID=181

the stock carberry IAT corrections are straight off the group-n map so should be a decent starting point for correction, just adjust the scale until your temp sensor readings are right.

thanks for the info, my mapper wants to use the maf hence me starting this thread.
my plan is to fit an IAT and wire it in on a dual circuit, so I can still use the maf.
I'll get a megasquirt one if recommended, thanks for the link

Thanks for the link, I'll either use the above or megasquirt.
I won't be scaleing the IAT, I'll leave that to the mapper! Just wanted to have one fitted and wired as to not use the maf.
You wouldn't know what wires connect to what when installing would you? Is it just 2x wires?

thanks
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yes just 2 wires - disconnect from the MAF loom where the standard IAT is and connect to the new sensor. Probably as handy to not do that bit until the mapper is on hand though otherwise the existing scale on your map won't be accurate.

I believe it's the brown wire and the green with red stripe you want - polarity doesn't matter.

Great, thanks!
Ive just been reading this
https://redirect.viglink.com/?format...rt-finish.html

mainly the part where he puts a connector in to retain the maf.
So, i shouldnt do this as it will affect scaling? I just didnt want to be messing about on map day, just swap plugs if that makes sense

Just re-read you post! No ill not plug into 'new' AIT sensor untill mapping.
Cheers

My wires don't seem to match the same colours as US maf. Can't see a solid brown wire or green/red as mentioned.
here is a pic of what I have. Could anyone help with this
https://cimg0.ibsrv.net/gimg/www.sco...b6e8973d6b.jpg
Cheers

Anyone?
No one running speed density....

I run speed density, my wiring was done by Andrew Carr when he mapped my car, I got IAT in place and just ran wires back to original maf wiring. Andrew just cut and soldered the ones he needed no extra charge

Thanks for the reply, I'll do the same as yourself.
Just wanted to have it ready as a plug and play in-between maf and IAT on topmount.
Wont be a problem for TDR if they have to soldier in in.
On a side note, I'm 99% sure it's the same numbered wires as I've seen on the US guide.
Anyhow, IAT is installed... Roll on Friday!

PINS 2 + 4 (BLUE + DARK GREEN/BROWN)
needed for iat sensor.

thats incorrect, in that pic its blue and brown/red ... hope you haven't damaged anything

You cannot wire two sensors together and hope to use both unless you are switching each out and in in turn just to say, and you should use intake air not charge air temp for this

bob

Hi Bob

thanks for your input, you've got me worried now, I'll have to talk to TDR.
I'm currently wired up to IAT mounted in top mount intercooler, just left of throttle body. I'm not switching between the 2 (maf/IAT) just have the connectors there if I needed to switch back at any point.
So I'm wired up wrong... That's reassuring!

Bob, could you confirm it's the blue + brown/red for a IAT in the top mount? Again I'm not using the maf at all.


Cheers Dan

https://cimg5.ibsrv.net/gimg/www.sco...9065137d67.jpg


It looks like i have an IAT sensor fitted, on my piping,

As it is before the throttle body but after the intercooler and turbo is that not as mentioned above charge temp ?

Instead of Intake Temp ? (Pre Turbo ??)

When is it beneficial to go mafless ?

Pro's & Con's anyone ?

I was always under the impression that you should use charge temps entering manifold and not pre-turbo? Hope Bob can chime back in to confirm.
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Cant get in touch with TDR to clear up this wiring issue, must have called at least 30 times!
What i dont understand is, how can the car make 340hp if the IAT is apparantly wired up wrong?
Ill send an email....anyone know if they are on holiday?

the car can still make power with the IAT not reading, it depends if the mapper has used the IAT readings to make any compensations. Could be they've not mapped in any IAT based changes as the sensor wasn't in place - with a view to adding them in when you came back with the sensor fitted up.

I also think it's the blue/white and red/black wires for your setup - confirmed on the simtek wiring guide for adding charge temp readings in via the standard maf/iat wiring:
http://www.simtek.co.uk/download/ecu-pinouts/

page 3 there shows MY01-05 (non DBW) pins 4 and 5 so I'd say those are the ones your looking for.


SmurfyBhoy - if you don't have a heat shield on your turbo then you could potentially be getting some heat soak on your temp sensor there, going mafless and using the air/charge temp readings to adjust fuelling as well as timing will mean the accuracy of the sensor is more important so your looking to avoid heat soak as much as possible. As I understand that's why most opt to not install them on the manifold directly. Going speed density should help avoid the "maf lag" you might get when having a large front mount core and longer pipe runs (vs the standard top mount short run) so you could have some gains from going down that route - your mapper will be able to advise you better though.

Again, appreciate the reply and info Bludgod:thumb:

So its looks like its wired in wrong,or had no intention of using the IAT. Ill just state that the IAT was fitted in the top mount before i went on rollers and provided wiring etc so Mark could connect up how he liked.
So basically i have a dummy IAT sensor, with no compensations being made......This is why i wish i had the time to learn how to map my own ****ing car

Again it would help if they picked up the phone, 3rd day trying to get in touch!

They maybe closed because of half term.
Or I think Mark's wife was due to have a baby any day soon,that is what Mark told me a couple of weeks ago.

Hello again Dave
maybe the case as you say. I'll wait till they get in touch. At the minute I've no idea if I'm good to drive the car or not.
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its also possible that the IAT pins have been moved at the ECU to match the way they've wired it under the bonnet

Spoke with Mark this morning, looks as if he connected them back up wrong after re-routing the wiring on top of the engine.
Thanks all for your input! I've learned a little as well

Had they been closed ?

Yes, they had Dave