I just completed swapping an 84 12A from a GS into an 83 GSL. I swapped all under hood parts and the exhaust from the 84 to the 83. I noticed a sensor after the converter that runs out the drivers side up through the underside of the drivers seat. This sensor was not on the 83 exhaust and I can't find a plug on the 83 harness for it. What is that sensor and do I need it for the 84 engine. I searched the forum and didn't find any reference to this sensor. I noticed some references to an exhaust overheat sensor that is on the passenger side, but I don't think this is it. This comes up the drivers side. Thanks in advance for the help.

 

Let me understand this correctly, you took all the parts from the 84 and put them in your 83? Why? The '84 runs a ECU, and adds more wiring, different exhuast with 3 stage converter.

Why not just strip the '84 engine and bolt it in to your '83?

The sensor in the exhaust will need the ECU and wiring harness from the '84 to work.

John

 

The '84 doesn't have an ECU if it's a 12a!

The GS and GSL '84 and '85s were just like the earlier models, with only minor changes such as the dash and some sensors. The GSL-SE was the one with an ECU and fuel injection, the others had carbs.

Sensor != (Does not equal) Important

Jon

 

Maybe things are different in Canada.

Sorry but you are wrong, its mounted just like a the 'SE, all then engine controls come from a wiring loom that is on the passenger side.

All 1984-85 Rx-7 have a ECU mounted under a access panel on the passenger floor.

Control Unit (Emission) - ECU, with 3 different part numbers listed:
N249-18-941D 12a MT- S, GS, GSL
N250-18-941C 12a AT- S, GS, GSL
N304-18-881R 13b GSL-SE

Also don't simplify the difference between the eariler model Rx-7 compared to the 84-85 models. There were a long list of changes. Caburetor, axle sizes, interior, suspension mounting, badging, front lower valance, exhaust system, emissions, power steering option.

If you have a 84-85 model I encourage you to pull back the carpeting on the passenger side.

John

 

All 12As have an "ECU" - an emissions control unit.

It's not just '84-85.


The simplest way to put the engine in would be to simply treat it as an engine change - the only part used from the '84 would be the bare block. Treating it as a swap and using everything from the '84 would be a monumentally pointless task, since the only difference (ENGINE WISE MIND YOU) was a relocation of the wiring harness and addition of a sensor here and there for further emissions refinement.

 

Prior to 1984 mazda refer to is at a 'control unit' and was up under the dash on the driver side.




J.

 

Does the same thing. Mazda just moved it for commonality reasons.

 

I didn't mean to create so much adversity. I am just trying to find out if that sensor is necessary. I should clarify my swap a little bit. I did not swap absolutely everything. I swapped as much as possible due to the condition of the 83.. As Peejay stated, there are surprisingly few differences in the two years. Slightly different exhaust and emmission parts. I'm just wondering if I can eliminate that sensor and not damage the engine.

 

I didn't mean to create so much adversity. I am just trying to find out if that sensor is necessary. I should clarify my swap a little bit. I did not swap absolutely everything. I swapped as much as possible due to the condition of the 83.. As Peejay stated, there are surprisingly few differences in the two years. Slightly different exhaust and emmission parts. I'm just wondering if I can eliminate that sensor and not damage the engine.

 

I didn't mean to create so much adversity. I am just trying to find out if that sensor is necessary. I should clarify my swap a little bit. I did not swap absolutely everything. I swapped as much as possible due to the condition of the 83.. As Peejay stated, there are surprisingly few differences in the two years. Slightly different exhaust and emmission parts. I'm just wondering if I can eliminate that sensor and not damage the engine.

 

I didn't mean to create so much adversity. I am just trying to find out if that sensor is necessary. I should clarify my swap a little bit. I did not swap absolutely everything. I swapped as much as possible due to the condition of the 83.. As Peejay stated, there are surprisingly few differences in the two years. Slightly different exhaust and emmission parts. I'm just wondering if I can eliminate that sensor and not damage the engine.

 

I didn't mean to create so much adversity. I am just trying to find out if that sensor is necessary. I should clarify my swap a little bit. I did not swap absolutely everything. I swapped as much as possible due to the condition of the 83.. As Peejay stated, there are surprisingly few differences in the two years. Slightly different exhaust and emmission parts. I'm just wondering if I can eliminate that sensor and not damage the engine.

 

You don't need the sensor. The engines opperate the same (they are the same engine). Its probably only for emmissions, and if your in Canada, then you don't have to worry about it. Your car is old enough to be exempt from emmisions testing.