revolutionmusclecars

Hello everyone! I have one that's really got me stuck! I did a 3.8 to LQ9 conversion in a 99 Camaro. It has the four bolt ls2 intake, three bolt conversion plate for the new Edelbrock tbody. With the IAT sensor connected, it reads about 275 degrees!!! and won't stay running without throttle. I disconnected it and the cars fires and idles but has a little bit of a surge. With the IAT disconnected it reads a steady 120 degrees. When I drive it, it surges bad under light load until I floor it and it comes alive. I also disconnected the MAF and it idles better but still surges bad under light, partial throttle. It is also throwing TCC codes. I have checked for vacuum leaks but so far haven't found any. Anyone have any ideas??? I appreciate your time and advice!!

jimmyblue

iTrader: (11)

First off, what "degrees"? Those numbers seem proper
for Kelvin scale but unlikely to come from an open or short
sensor or any likely defect (though open IAT reads very
low temp as-designed, which 120K is). But why you'd be
seeing a Kelvin scale reading, makes no sense either.

revolutionmusclecars

Hey Jimmyblue! Thanks for your reply! It is definitely reading degrees Fahrenheit. I'm using a MAC scanner that is very limited in what it can do. This is what all the readings are currently at idle:
MIL Status off
abslt tps 0.0
eng speed 601
calc load% 1.6
MAF LB/M .69
MAP "HG 14.5
Coolant *f 142
IAT *f 120 -unplugged
Ign Adv 16
Secnd Air Atmos
ST FTRM1 0.0
LT FTRM1 21.9
St FTRM2 0.0
LT FTRM2 25.0
Fuel Sys 1 open
Fuel Sys 2 open
O2s11 (v) .045
ST FTRM11 (%) 0.0
O2S12 (v) .440
O2S21 (v) .025
ST FTRM21 (%) 0.0

revolutionmusclecars

Anyone have any idea where to go on this??

bmcbride

Did you ever figure this problem out mines doing same thing

bmcbride

Did you ever figure this out mines doing same thing

jimmyblue

iTrader: (11)

Something I saved, probably from here, a very
long time ago....

Shorted IAT will read like very high temp.
Open IAT will read like very low temp.

Both will jack fueling and spark around. With bad
effects on starting and idle (and generally all over).

When in doubt, recommend you pull battery power,
pull PCM connectors and measure the IAT pin from
connector pin assigned, to a connector block ground
and look for ~ 2500 ohms give or take. That's what
the PCM "sees".

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IAT/CTS sensors
IAT and CTS sensors (Inlet air temp and cooland temp). These are sensors that provide a variable resistance according to temperature. IAT is sometimes referred to as MAT (Mass Air Temp)
Temperature (C) Temperature (F) IAT resistance CTS resistance
100 210 185 177
90 194 241
80 176 332
70 158 450 467
60 140 667
50 122 973
40 104 1800 1,459
30 86 2,238
20 68 3400 3,520
10 50 5,670
0 32 7500 9,420
-10 14 13,500 16,180
-20 -4 25,000 28,680
-30 -22 52,700
-40 -40 100,700 100,700