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Faulty MAT Sensor

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Old 07-05-2019, 01:17 PM
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Car: 89 Camaro RS - White w/ Orange
Engine: 305 V8 TBI
Faulty MAT Sensor

I apologize ahead of time if this was answered somewhere else, but I've been struggling to find an answer.

Background: Recently purchased an 89 Camaro 305 V8 TBI. Since owning, I've replaced the Fuel Pump, Filter, and Fuel Relay. Car was running great. Ran into an issue recently where the car starts to choke out when accellerating after the car was warmed up. I replaced the MAP sensor under the guidance of my mechanic, but that did not help . I pulled the plug on the MAT Sensor (behind the air filter) and the problem has gone away. Problem I have now is that the check engine light comes on now once the car warms up. The other problem I have is that I can't find a replacement sensor. Are there any recommendations on what sensor I need to purchase to replace the bad one. I can add a photo later if that would help.
Old 07-05-2019, 02:43 PM
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Let’s Map It Out

MAP and MAT terms are frequently swapped.

If you can post a photo, that will clear it up.


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Old 07-05-2019, 02:57 PM
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Re: Faulty MAT Sensor

MAT = Manifold Absolute Temperature
MAP = Manifold Absolute Pressure

MAT is usually referred to as IAT Intake Absolute Temperature.

AFAIK TBI doesn't have a sensor for that... might be why you're having trouble finding one.

TBI doesn't have a choke. That's something carbed cars used to have. Whatever your car is doing, it's not related to "choke".

What color are the wires going to whatever you're disconnecting? How many in the plug? Where is it EXACTLY? What code do you get when you hook up your OBD1 scanner and read the codes?
Old 07-06-2019, 12:39 AM
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Re: Faulty MAT Sensor

TBI, as with all forms of speed density that I'm aware of, has an IAT (Intake Air Temp) sensor. It does not have a manifold temp sensor...... though in the world of 80's/90's GM fuel injection they are pretty much always the same thing. Some are threaded, some are plastic push-in, and some are brass tip while others have a bird cage but they all share the same resistance values and wiring connector. Coolant temp, manifold temp, air temp.... same same.

GD
Old 07-06-2019, 11:35 AM
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Re: Faulty MAT Sensor

Here's some photos. I haven't gotten a chance to pull the engine code yet. The sensor I disconnected is the round one seem in the photos.

Old 07-07-2019, 11:10 AM
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Re: Faulty MAT Sensor

LIB; I'm sorry, I was misshapen, I guess these cars DO have an IAT sensor.

That one looks kinda like it's missing something. Might have something to do with why it doesn't work right.

Try searching for IAT sensor. Might also be called "air charge sensor", "air cleaner temp sensor", or various other names along those lines.
Old 07-07-2019, 11:20 AM
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Re: Faulty MAT Sensor


Old 07-07-2019, 02:05 PM
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Re: Faulty MAT Sensor

Thanks for finding those parts. Are you saying that I need both parts?
Old 07-07-2019, 02:08 PM
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Re: Faulty MAT Sensor

You need the top one.

The other 2 are the coolant temp sensor. It goes into the intake manifold (INT MANIF) which might be why the search term "intake" pulled them up.

I'm NOT saying of course, that you DON'T need the other; you might, for all we know out here; only, that the one you showed, is a thing unto itself and is not involved with the other.
Old 07-08-2019, 10:36 AM
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Re: Faulty MAT Sensor

Thanks for the help. I ordered the part. I'll report back in once it's installed.
Old 07-12-2019, 08:00 PM
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Re: Faulty MAT Sensor

I replaced the sensor and the car runs better and I no longer get a check engine light. I seem to be in business. Thanks for the help, folks!
Old 07-12-2019, 11:23 PM
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Re: Faulty MAT Sensor

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