High IAT readings

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Jul 30, 2006 | 03:46 PM
  #1  
Ambient Temp. =94*F and 56% Humidity

Im working on a friends 89' LB9 and making some datalogs today im noticeing that the IAT is reading between 210* and 250*. The CTS is staying at a steady 175* throught the runs. Even on the highway im getting around 220* IAT reading.

Im trying to work out some detonation issuses but im not getting a a specific area of detonation. Its random everyday. I can get the tune down pretty nice but when he leaves at the end of the day he says he starts get detonation again. Same thing over and over. He's gonna change the IAT to see if that helps or changes anything but im still looking for some type of IAT lookup table or something.

Any suggetions? This is a 89' with an ANYX base. Fresh LB9 10.5cr, Fresh 081 Heads, Comp (08302-8) 210-220 .480 .480 112*, T5 and Full Exhaust.

Thanks
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Jul 31, 2006 | 12:42 PM
  #2  
That does some high even if the IAT is in the stock location threaded into the bottom of the plenum. There have been posts by people with knowledge of the 6E mask that the IAT is used for little more than a switch for EGR operation and doesn't affect fueling or timing. If true then fooling with the IAT may not help with the knock issue. A search may yield more specifics.
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Aug 1, 2006 | 06:44 AM
  #3  
The easiest test of the IAT is to compare it to the CTS. Do this after the car has sat overnight. They should both be within a few degrees of each other.

The high IAT along with detonation issues may be caused by a faulty EGR.

RBob.
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Aug 1, 2006 | 08:59 PM
  #4  
Quote:
The high IAT along with detonation issues may be caused by a faulty EGR.
Bingo. That was determined by the owner earlier today. Thanks for yalls help.

We was all on the right track. :cheers:
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