Running Stock IAT with MS?
 

Hi all!

Currently am installing my MS2PNP on my stock 1.8 engine 1995. The turbo is being installed in another week or two, but id like to have the car up and running so I can familiarize myself with the bare bones of MS and tuning before the car gets dyno tuned. Id like to at least converse with my tuner about the basics of what he's doing.

I already have a bung setup on my IC piping for my GM IAT sensor, but clearly, I can't use that pre-turbo. How would I go about setting up the stock IAT sensor to be used temporarily? I've searched for info regarding this, but if it's out there, it's lost in a sea of "GM IAT install" threads.

I'm making a few assumptions here. First, that the thermometer tables need to bee running on IAT and not coolant temps for my purpose. Also, that il have change resistor values to get the stock IAT sensor to read properly.

I'm completely new to this so any input is appreciated!

https://trubokitty.com/#/tune

Bottom of that page.

After reading up on a few more threads I could find and trying to understand the TS software, pretty sure I see multiple misunderstandings I had. Was wondering how coolant temps had anything to do with running the engine haha.

I believe I mostly sorted this out on my own by selecting the "Mazda" sensor instead of "GM", but my temps are reading 112F when its 95F ambient. Imagine this is a negligible difference but let me know otherwise.

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@SpartanSV Appreciate that link! That's what I needed.

Interesting. I have ‘99 and have been using the RX-7 calibration for CLT sensor. I’ll have to compare Scott’s ‘99 values to the RX-7 and see how much it effects my true high and low temperature readings.

Bear in mind that the factory sensor doesnt respond as quickly as the GM one (one of the reasons people use the GM one)

So it's quite possible it's just stayed a bit warm from install. Or just that it's picking up the above ambient air in the engine bay.

Not enough difference to care about, I don't think. Here is plot of the RX-7 (Blue) vs Trubokitty.com 99+ (Red) with a 2.49K bias resistor:
https://cimg4.ibsrv.net/gimg/www.mia...34016960c3.png

You can drop the GM IAT into the bottom of the factory air box beneath the air filter temporarily and let the wires pass through the seam if you wish. That can get you started without removing any of the other factory components.

Speaking of, is there a male plug that plugs in the OEM harness? I would love not to cut the OEM connector off and just make a pigtail.

I didn't cut the OEM connector off. I did the thing where you stick a pin in each of those two holes in the connector and then you fold the wires back over and wrap everything in the self fusing tape.

That's a military splice for those who may want to look up the right way to do it. Works extremely well for that situation.

You can buy this connector to have a bit better fit and finish.
https://speedyefi.com/product/94-miata-maf-delete-plug/

That would look clean but I have a NB2. I will search a bit further; if nothing is to be found, I will cut the wires for a Delphi GT150 female (to plug onto the GM IAT), and make a pigtail/extension with a male GT150 on one end and the OEM IAT plug on the other.

On my 1.6, I had zeroed out the MAT compensation curve while tuning initially and still haven't actually put it back yet. I did all my tuning when it was in the 30-40f range and just letting EGO handle it has been good enough (if a bit rich sometimes).

Long story short, don't worry about it too much.