LS1/Vortec pcm's and harnesses - what can be used together?
11-17-2009, 09:16 PM
#1
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LS1/Vortec pcm's and harnesses - what can be used together? I've got a 2005 5.3 truck motor, truck pcm, and truck harness. The truck harness isn't pretty on the LS1 intake, the injector plugs are wrong, and the main wiring comes in from the wrong spot, ie the front of the motor... So, can I:
1. Use my 2005 truck pcm (green/purple connectors) with any old LS1 harness, or do only certain years work (or none)?
2. Or do I need an LS1 pcm to go with the LS1 harness as well?
3. The pcm will get reflashed anyway, any advantage to using a car pcm over a truck pcm, assuming either would work with either harness?
All my book says is that the 97-98 LS1 harnesses are different from the 99-02, and that the Vortec harnesses are different from that... No kidding, right?
Anyone shed some light? Thanks,
Jesse
1. Use my 2005 truck pcm (green/purple connectors) with any old LS1 harness, or do only certain years work (or none)?
2. Or do I need an LS1 pcm to go with the LS1 harness as well?
3. The pcm will get reflashed anyway, any advantage to using a car pcm over a truck pcm, assuming either would work with either harness?
All my book says is that the 97-98 LS1 harnesses are different from the 99-02, and that the Vortec harnesses are different from that... No kidding, right?
Anyone shed some light? Thanks,
Jesse
11-18-2009, 11:21 AM
#3
Do you mean blue/green pcm? Are you running drive by wire? If you are you can use the Blue/Green PCM and modify a red/blue harness (99-02) by adding additional grounds and O2 grounds to work with the blue/green PCM.
If you arent running drive by wire, you can convert to a red/blue PCM and harness this will include the correct EV1 injector connectors. Remember that the tune/pedal/tac/throttle body must match.
If you arent running drive by wire, you can convert to a red/blue PCM and harness this will include the correct EV1 injector connectors. Remember that the tune/pedal/tac/throttle body must match.
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11-18-2009, 02:33 PM
#4
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What color is your crank sensor, gray or black?
Do you mean blue/green pcm? Are you running drive by wire? If you are you can use the Blue/Green PCM and modify a red/blue harness (99-02) by adding additional grounds and O2 grounds to work with the blue/green PCM.
If you arent running drive by wire, you can convert to a red/blue PCM and harness this will include the correct EV1 injector connectors. Remember that the tune/pedal/tac/throttle body must match.
If you arent running drive by wire, you can convert to a red/blue PCM and harness this will include the correct EV1 injector connectors. Remember that the tune/pedal/tac/throttle body must match.
I will not be using DBW, I have a 99 cable TB, 99 LS1 intake/fuel rail/injectors, and it's a 24x reluctor motor.
So if I want to run the LS1 Camaro harness, I need a Camaro PCM (which is red/blue) to run with it?
Thanks guys!
11-18-2009, 06:40 PM
#5
You can use either the truck or car harness, if you're running the LS1 intake and not putting it in a truck, that can take advantage of the truck fuse box relay center, you're better off starting with the car harness. It doesn 't really mater if the PCM is from a car or a truck, it just needs to be flashed with the correct OS for your motor and tranny
11-18-2009, 07:33 PM
#6
What is the service number on your 05 computer? It is likely you could run the blue/green PCM on a 99-02 LS1 blue/red harness, program PCM for 04 GTO, which was LS1, Cable throttle.
Just out of top of my head, this should work without any repinning of the PCM connectors. Codes in the PCM for the oxygen sensor heater circuit monitoring would need shut off, as the 03+ pcm's control the Ground side of the o2 heaters. The blue/red harness will have the O2 sensor heaters grounded to the engine block. No biggie at all.
All the sensor grounds, 5v references, and signals back to the PCM are in the same place 99-07(classic body truck) PCM's.
Just out of top of my head, this should work without any repinning of the PCM connectors. Codes in the PCM for the oxygen sensor heater circuit monitoring would need shut off, as the 03+ pcm's control the Ground side of the o2 heaters. The blue/red harness will have the O2 sensor heaters grounded to the engine block. No biggie at all.
All the sensor grounds, 5v references, and signals back to the PCM are in the same place 99-07(classic body truck) PCM's.
11-18-2009, 08:53 PM
#7
As stated above, there are different ways to skin this cat. Since you are going with drive by cable, I would recommend just using the red/blue stuff. By the way, if you move forward with the blue/green make sure that the PCM you are using has the drivers for the IAC. Just because it is blue/green doesnt mean it will have the drivers. Just an FYI.
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11-19-2009, 07:45 PM
#8
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What is the service number on your 05 computer? It is likely you could run the blue/green PCM on a 99-02 LS1 blue/red harness, program PCM for 04 GTO, which was LS1, Cable throttle.
I'll definitely need that IAC, how do I tell if this pcm has iac drivers?
For anyone else in a similar situation, Pocket pointed me to a nice harness rework thread here: http://www.thirdgen.org/techboard/lt...rt-finish.html
Since you are going with drive by cable, I would recommend just using the red/blue stuff.
If I have to I'll pick up a camaro pcm, but I'm hoping what I have will work.. Any idea how to tell about that IAC driver? BTW - thanks for the comment, saw your Biscayne up there @ psi 
Muchos Gracias
11-19-2009, 09:34 PM
#9
You got lucky. 12602802 has the IAC drivers.
On second thought, we just had a couple of harnesses come thru here with the 2802 PCM and neither one would work with a cable throttle body.
It may have been the 2801 that had the IAC drivers.
Sorry about that.
On second thought, we just had a couple of harnesses come thru here with the 2802 PCM and neither one would work with a cable throttle body.
It may have been the 2801 that had the IAC drivers.
Sorry about that.
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91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
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91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
Last edited by Speartech; 04-15-2010 at 03:48 PM. Reason: new info
11-20-2009, 11:00 AM
#11
Thanks Spartan. Going to see how much boost I can push through the LT1 in the Biscayne. I have an LS2 just waiting to go in.
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11-21-2009, 12:11 PM
#12
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You got lucky. 12602802 has the IAC drivers.
If you get creative, you can tuck the harness pretty good on the ls1 intake, and if you have FRC's it wont even be seen
Last edited by spartanv8; 11-23-2009 at 12:02 PM.
11-27-2009, 09:53 AM
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Finished splicing the injectors, and working them into the new harness... Last pic is a diagram showing which wire does what from one style connector to the other, in case anyone else needs it.
Last edited by spartanv8; 11-28-2009 at 02:05 PM.
11-28-2009, 02:06 PM
#16
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I've got the original truck injector pigtails if anyone wants them, pm me
Back view of the motor. Luckily all that wiring will tuck away nicely once its bundled and loomed.
Back view of the motor. Luckily all that wiring will tuck away nicely once its bundled and loomed.
11-29-2009, 10:10 AM
#17
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Coincidentally, I've got a 3 wire alternator, does the blue wire that went to the body/dash harness need to be connected to anything? I've heard its just for an indicator light..
