Wire a 1994 lt1 wire harness to work with a 1995 lt1 wire harness
10-12-2009, 12:13 PM
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Wire a 1994 lt1 wire harness to work with a 1995 lt1 wire harness
Ya new guy here and i was wondering.. how could i wire a 1994 wire harness to work on a 1995 firebird ? I changed out the 1995 lt1 wire harness because it fried up etc
so i was thinking a 1994 wire harness would work for it to solve the issue of other one fried up, and now only thing that happens is the engine cranks but seems like i'm not getting any fuel at all 
how could i rewire it to make it work for the 1995 firebird formula lt1. I just want it to fireup and stay working for now. anything would help! thanks dudes and dudets.
so i was thinking a 1994 wire harness would work for it to solve the issue of other one fried up, and now only thing that happens is the engine cranks but seems like i'm not getting any fuel at all how could i rewire it to make it work for the 1995 firebird formula lt1. I just want it to fireup and stay working for now. anything would help! thanks dudes and dudets. 
10-12-2009, 05:44 PM
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Car: 92 Firebird
Engine: Supercharged 6.0
Transmission: T56
Axle/Gears: 8.8 3.73
Re: Wire a 1994 lt1 wire harness to work with a 1995 lt1 wire harness
1) This is a third gen site, refer to LS1tech or other places
2) At some point the harness changed slightly, one wire was added to the 4L60E connector but that should not affect startup. OBDII added several connectors that are very necessary to startup, but 95 should still be OBDI
3) Fuel pump wiring shouldnt make any difference regardless of the year you put it in. Find the fuel pump prime connector and add 12v to it. The pump should come on. If it doesnt either the relay is bad or the relay isnt getting battery power
2) At some point the harness changed slightly, one wire was added to the 4L60E connector but that should not affect startup. OBDII added several connectors that are very necessary to startup, but 95 should still be OBDI
3) Fuel pump wiring shouldnt make any difference regardless of the year you put it in. Find the fuel pump prime connector and add 12v to it. The pump should come on. If it doesnt either the relay is bad or the relay isnt getting battery power
10-12-2009, 08:07 PM
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Car: 92 z-28 vert heritage edition
Engine: LT-1
Transmission: 700r4
Axle/Gears: 3.08 posi
Re: Wire a 1994 lt1 wire harness to work with a 1995 lt1 wire harness
The 94 & 95 harnness should be the same I think they changed it in 96 when they went to the vented opti and started using a crank position sensor. You might want to look at the pin printout for both and see if there is any differences. If so than that's gonna be one of your problems. You should also make sure the vats is dissabled. That will cause a fuel cut off hence no starty starty. Oh yea that last post was a little ironic, what's the point of this area for swaps if all you can tell us is that this is a third gen site. I think that's why he is here asking questions.
10-12-2009, 10:18 PM
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Car: 92 Firebird
Engine: Supercharged 6.0
Transmission: T56
Axle/Gears: 8.8 3.73
Re: Wire a 1994 lt1 wire harness to work with a 1995 lt1 wire harness
The point is this is TGO, not LT1.com. If it doesnt pertain to 3rd gens, the thread is usually locked
Direct quote from LT1swap.com
The OP was asking if there were any differences in the harnesses. They were listed. He also wanted to know how to test/rewire the fuel pump relay, also addressed. Keep your swap (its a stock for stock, not swap) and VATS (no the issue) mess to yourself. If he has those problems they will be dealt with assuming the thread isnt locked
1994 started first year for 4L60E as the automatic trans option. This is the electronically controlled transmission. The 94-95 PCM's are identified by service number. 16188051. All 94+ LT1 PCM's are aluminum in color with 4 rectangle plugs. 94-95 PCM's can be flashed through the diagnostic port using rather inexpensive hardware and software. Click here for more info on that. In 1995 the 4L60E changed slightly, and an additional solenoid was added to the valve body. This required an extra wire to be added for 1995 models. You can determine 94/95 harnesses by looking for Pin U on the transmission connector. Also, 1994 4L60E transmission WILL NOT work properly with 96-97 PCM's.
The OP was asking if there were any differences in the harnesses. They were listed. He also wanted to know how to test/rewire the fuel pump relay, also addressed. Keep your swap (its a stock for stock, not swap) and VATS (no the issue) mess to yourself. If he has those problems they will be dealt with assuming the thread isnt locked
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