HAC sensor???

[YoNkErS87t]

Can someone explain what the HAC sensor does for the car. My friend has a 89 with 88 swap done and doesn't have a HAC sensor I'm just wondering how that would affect the car. He is not driving the car yet, but will in the up coming weeks.

There is a spot for the Sensor in the glove box, but we're just wondering how it would affect setting the timing and what not.

 

[shaeff]

check out this thread, my posts, it covers the HAC:


http://www.supramania.com/forums/showthread.php?t=946

-shaeff

 

[chevyeater]

The High Altitude Compensator is a barometric pressure sensor. It is used in the calculation of mass air flow along with Karmann Vortex frequency and Intake Air Temperature inputs. Without a functional HAC, the car will run differently according to barometric pressure. It will run richer in low pressure conditions and leaner in high pressure conditions. The closed loop operation will compensate fuel trim to some extent. Spark advance is also pressure corrected but there is no "fallback" sensor to make up for the lack of correction without the HAC. Spark timing is advanced inversely to barometric pressure.

The corrections made on account of the HAC sensor are small under normal conditions. In extreme conditions, such as a hurricane or driving through a large mountian range, the corrections can be significant.

 

[IJ.]

Brian: No wonder you have a headache !

 

[chevyeater]

LMAO, IJ.

 

[Justin]

so the 86, 87, and 88's do not have the HAC, but the 89-92's do?


does the entire year of 89 have it, or just the latter half, since they changed a bunch of crap halfway through 89....

 

[shaeff]

so the 86, 87, and 88's do not have the HAC, but the 89-92's do?


does the entire year of 89 have it, or just the latter half, since they changed a bunch of crap halfway through 89....

no, they all have one. the 86.5- early 89's have an EXTERNAL HAC, which plugs into the engine harness near the glove box, and the late 89- 92's have an internal HAC. (inside the ECU)

-shaeff

 

[Bishop92t]

Every 7mgte has the HAC, it's just built into the ECU somewhere around 88. Before it was built in it was located under the glove box.

 

[Justin]

Super