Iat

[rleete]

1994, installing the FFS cdoldside kit I bought (used) almost 2 years ago.

Step two, it says to remove the IAT, that it comes out with a twisting motion. Later on (step 29), it shows mounting the IAT in the end of the air filter. My car looks nothing like the pics in the install instructions. So, consult the trusty Haynes manual. It says the IAT is built into the MAF. No separate sensor.

So, which is it? Pretty silly to confuse us with someting like this right off the bat. I assume I can just kinda ignore this step?


Megasquirt, which I am also installing, suggests removal of the MAF, and replacing the IAT with a GM/generic sensor. Anyone else do this? Recommendations for or against?

[Tom @ Fast Forward]

Yes. In your case, ignore that step.

If you are going to eliminate the MAF, you will have to have an IAT in the intake manifold.

[rleete]

Any reason to not use the location for the 5th injector? I'm not using it, instead going with larger primaries (460cc, I think).

I've read that instruction booklet about 100 times already, but it's different when you're actually pulling bits off the car.


Oh, and thanks for the quick response.

[Tom @ Fast Forward]

My previous comment was the sum total of my MS knowledge. Someone else will have to take it from here.

[WillM]

The source of the confusion, I think, are the instructions. The instructions for 94-97 Miatas are full of pictures and references to 99-05 cars. In 94-97 model years, the IAT sensor is an integral part of the MAF In this case, the MAF both meters air AND measures air temperature. If you remove the MAF, you'll need to replace it with two new sensors, one to meter air, one to measure air temperature.

With a MegaSquirt, you'll be better off removing the MAF and using the MegaSquirt's MAP sensor to meter air. You should also use, as "they" recommend, a GM air temperature sensor. The DIYPNP instructions, available on DIYPNP's website, shows you how to splice a GM AIT sensor into the stock MAF/AIT wiring harness. It is an easy procedure.

I have a MegaSquirt controlling my 95 coldside. I went the extra mile and drilled & tapped the bottom of the intake manifold to fit the GM AIT. If you go that route, be sure to test fit the manifold and pick the sensor location with the manifold on the head. The space below gets tight with the manifold brace and oil filter in place.

Keep in mind that you'll also have to remove the supercharger from the manifold, to do the job right and clean-up properly.

[rleete]

Thanks, that is what I was going to do. Sensor was ordered last night, along with the tuning cable. I really need to get this car boosted this summer.

Do you happen to have any pictures (or even a crappy sketch) as to the location you used?

[WillM]

I'll try to snap a pic, but it is not an easy location to get to.

If I recall correctly, I tried to get the sensor centered on the manifold, in both directions. Right between the runners for cyl 2+3.

If you can, try to go with the smaller GM AIT. The standard sensor is freakin' huge (3/8", I think). There is a much smaller (1/8", I think) that functions better, and would likely fit in one of the existing bungs.

[rleete]

I ordered the one from DIY autotune. It's 3/8" NPT, I believe.