Hey guys. I got my K&N and I'm ready to build my cold air. Looks easy...only one question: What did you guys do with the sensors that connect to the old intake? One(at the airbox) is electrical(for emissions??)--the other is a plastic hose connecting the tubing right in front of the throttle body to the valve cover(a breather??). Do I need to connect these to my new cold air or does it really matter? Oh by the way, it's a 91 3.1L bird w/ no MAF if that matters.

 

Squirrel,

The hose is the crankcase breather tube. This needs to be connected to a source of filtered air, like the base of the filter adapter. The sensor you describe sounds like the IAT sensor. It is used to adjust the fuel mixture and spark curves to compensate for intake air temperature. If you remove the sensor, the MIL lamp should turn on and the ECM will use base lookup tables for fuel and spark calculations.

You really need to install the sensor somewhere in the intake air stream, but it doesn't have to be in any exact location. The farther from the throttle body, the better, since the heat radiated from the TB can cause a leaner mixture and retarded timing due to a false high temperature indication.

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Later,
Vader
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"I cannot take this any more... Saying everything I've said before..."
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KaleCo Auto Parts

 

Thanks Vader.

 

Putting the MAT in the rubber boot in front of the TB is fine to relocated it, and is where TPIS recommends you put it.

Inspite of my own personal misgivings about the relocated MAT (it causes the engine to run WAY TOO RICH as the GM eprom expects it to be in the plenum), installing the MAT in the rubber boot in front of the TB will give you an accurate intake temperature. I've had mine there for over a year and it reads with 1 degree of the ambient air temperature.

Shouldn't the MAT be in the plenum anyway?