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Early model tb to later model ls4

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Old Nov 16, 2012 | 01:19 PM
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Default Early model tb to later model ls4

Ive just learned that the earlier model ls4s came with a 8 pin throttle body while the later models have a 6 pin connector. Anyone able to shine so light on this rewiring subject. ive search and cannot find the wiring diagram.
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Old Nov 16, 2012 | 02:47 PM
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http://www.torquerush.com
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Old Nov 16, 2012 | 05:07 PM
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I just need a rewire as its still a ls4 throttlebody.
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Old Nov 16, 2012 | 08:33 PM
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I just learned this too!
Follow 91parkave lead..
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Old Nov 16, 2012 | 08:48 PM
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Only one issue I bought the tb from you as a cheap alternative to purchasing a new one. That's 225 dollars plus the 50 I paid you...
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Old Nov 17, 2012 | 11:33 AM
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Should be able to repin your harness for under $5
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Old Nov 17, 2012 | 11:39 AM
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I'm having trouble finding the diagrams. Any idea what the two extra pins on the early models are?
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Old Nov 17, 2012 | 11:41 AM
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Here is the 8 pin
https://ls1tech.com/forums/ls4-perfo...ttle-body.html
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Old Nov 17, 2012 | 11:45 AM
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I'm not a 100% this will work? But for the price of the plug I'd try it. I have the pt# for the 6 pin around here some where, but I'm walking out the door as soon as I get a chance I'll post it up.
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Old Nov 18, 2012 | 07:33 AM
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Here is the pinout for the 8-pin LS4 TB.

Code:
Pin	Wire Color	Circuit No.	Function
A	D-GN		485		TP Sensor 1 Signal
B	L-BU		6295		5-Volt Reference 2
C	TN		2752		Low Reference
D	PU		486		TP Sensor 2 Signal
E	YE		581		TAC Motor Control - 1
F	BN		582		TAC Motor Control - 2
G	GY		2701		5-Volt Reference 2
H	L-BU/BK		6297		Low Reference
Notice it has dual Low Reference wires (grounds) and dual 5-Volt Reference wires. If you look closely at the wiring schematics (atleast on the E67 ECM), the Low Ref wires are connected internally and the ECM uses two banks of 5V ref with all the 5V Refs connected to one of these two banks.

To wire up a 6 wire TB, you can either wire the redundant wires together (splice the two Low Ref wires together, then connect to the single Low Ref wire on the 6-wire TB and do the same for the 5V ref wires) or just leave one of the Low Ref and 5V Ref wires unconnected.
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Old Nov 18, 2012 | 09:41 AM
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I believe you need the 8 way connector, pt# 13530777. You can order from Mouser Electronics. You'll also need 2 pins to splice into your wiring harness, pt# 121918-L. I would 12 or so of the pins in case a couple of them get screwed up. Like I said I'm not a 100% on this, but I would try it for the price.
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Old Nov 18, 2012 | 09:54 AM
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Davidgxp shipped me the harness cut from his car with the throttle body. Is this like the truck tb where there's a shot the tb won't work correctly? Ie they use different voltage?
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Old Nov 18, 2012 | 10:05 AM
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I don't know where you guys get these diagrams. I can't find the 6 pin diagram. Thanks for everyone's help incase that wasn't implied.
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Old Nov 18, 2012 | 10:06 AM
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Dumb question...any benefit to the earlier throttle body or is it just different harness?
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Old Nov 18, 2012 | 11:30 AM
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Originally Posted by baltsk8er69
I don't know where you guys get these diagrams. I can't find the 6 pin diagram. Thanks for everyone's help incase that wasn't implied.
I have a 2007 Impala Factory Service Manual on the desk... only way to do a custom swap (LS4/F40 6 speed into an 88 Fiero).

Here is 6 wire pinout the LS2:


What throttle body pinout are you looking for?
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Old Nov 18, 2012 | 11:55 AM
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I needed a new tb. I bought a stock ls4 tb from Davidgxp. Only to find the 06 tb is 8 pin. The 08(mine) is 6 pin.
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