I found a couple more things during my engine swap that I would like to know what they are and I can't figure it out. First thing is a little sensor looking thing that plugs right into the bottom side of the plenum in the back with one single connector going to it. What is it??

Second, on the passenger side firewall with the wiring harness there are two connectors. Once connector is a two wire connector, one green and one black. Next to it is a single one wire connector with a red wire. The connectors are a long type connector. Different looking than most of the others on the engine. I'm trying to figure out what these are because the red single wire connector looks quite fried and the two wire connector next to it has a little melted plastic on it which I'm guessing is from the fried connector. Any help with this would be greatly appreciated.

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1986 Trans AM
305 TPI
Well over 200,000+ miles (speedo/odometer non-funtional! Odometer reads 142,000)
4 Wheel Discs
9 bolt Borg Warner Rear (2.77's....oh joy) :P
Completely Stock
Current Project: upgrade to a 355 TPI, 6" rods, 9.7:1 Compression, Stock TPI ported, 24#/hr LTI injectors (cleaned and flowmatched by Cruizin Performance), Hedman Shorty Headers, 3" exhaust with 80 series flowmaster, SBC 993 heads completely redone and modified for 1.6 RR, Comp Cams XE262-14 TPI Cam, Holley AFPR, TPIS airfoil, MSD wires, MSD 6-AL Ignition, Hypertech hot coil.

The sensor under the back of the plenum is the manifold air temp sensor. The two connectors, I just don't know...... Someone else will though.

If that's the Manifold Air Temp Sensor then what's the sensor that plugs into the front of the passenger side of the intake?

The green & black wires in that connector might very well be for the A/C accumulator switch.

the single RED wire belongs in the same area, I cannot remember what it does off hand.

John


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G O D BLESS AMERICA

http://www.3rdgenformula.com
87 Formula 5.1 TPI Auto Modified (Yellow/Black)

87 Formula TPI (5 Speed) Yellow/Gray STOCK

14.8sec 1967 Buick Riviera
1990 Buick Riviera (driver)
83 Camaro
83 T/A

Sounds like AC stuff to me. Could explain why my AC never put out cold air. Oh well, my AC has been eliminated for now anyhow. Thanks for the help.

the air temp sensor is under the plenum, i know this cause i replaced mine today.
but i can't think of another sensor, is in on the upper plenum or the base?



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- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series

http://www.geocities.com/david_angel_16

The fried connector you're referring to is for the cabins heat/vent fan. it provides juice to the blower motor directly from the battery when at max. if your fan is not working at its max setting, but is on lower settings, this little guy is the culprit.

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'89 TA - 5.7 TPI (L05, was originally a 305TPI), T5-WC, 3.08 Posi (Drum)

Fan works on ALL cycles at ALL speeds.

The sensor on the front of the engine is the CTS - coolant temp sensor. The sensor under the plenum is the MAT - manifold air temp sensor. If you look you'll notice they are the exact same part, even share a PN for most years.
As to the others, dunno, never looked at an 86 that hard. Perhaps vader will chime in, he has an 86 and i'm sure he'll know if he lookst at it.

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Ed Maher - Moderator @ The TPI & Carb Boards
92 Z28 Convertible - Quasar blue / Tan top
305 TPI A4 2.73 - 14.7 @ 93.6
Stock except ported plenum and dual cats
-=ICON Motorsports=-

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die

I posted this over on the electronics board and Vader already responded. His guess was something to do with the AC/fan as well. Considering my AC has been eliminated and the heaters works just fine on all cycles and all speeds I'm not too worried about it anymore.

On your 86, there are two sensors in the front of your manifold.

- Cold start injector switch (looks like a fuel injector plug)
- ECM Coolant Temp Sensor (small oval)


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Mike Metzler (Desert86Roc)[*] Check Out:SpeedWorldMotorplex.com[*] Check Out:Chevrolet F-Body Online Part & Illustration Manual[*] www.MetzlerRacing.com

Best ET @ 1250 ft[*] 15.352 @ 91.215 mph (uncorrected)

Thanks, I was wondering what that other one was. I noticed that one I had unplugged came undone just like the injtectors. Makes sense now. Any idea on how often those go bad?

if you are talking about the one under the TPS, then it is the IAC motor.

yes the red wire goes to the a/c relay located on the evaporater housing. the black and "green" is actually a blue color which goes to the low pressure switch that is on the accumulator. i have the same car you do just with 3.27 gears.

Actually the IAC motor is located on the throttle body, I was talkin' about the two on the intake BELOW the throttle body. I know what they are now.... thanks