Harness question

[XLexusTech]

Hello, ripped out my dash and did some celan up work on both sides of the firewall. I want to take advantage of the easy access and do all of the wiring, AC, ducting before i weld the dash in.

I was looking at the GMPP http://store.chevroletperformance.co...-19201861--%3E
but was wondering if their might be a better route? Also I may go LSA can I purchase a harness that will work on LS3 or LSA and pick up the controller later?
Do speartech or others make a better option?

[Schwartz Performance]

There are several companies making harnesses, you can try Howell Engine Development or PSI Harness too. Cost of the Gmpp is really good though.. But not as "custom" as the others obviously. I believe the LSA will be the same harness but different sensors so the computer tune is different of course.

[68sixspeed]

I'm running the gmpp harness and have no regrets, it installed easy, is well made, and programmed fine with HP tuners to adjust for my cam change and compensate for the air intake/MAF location.

Pretty much everything stays under the hood, the only thing passing into the interior is the obd2 port, gas pedal plugin, and a hookup for switched power and gauges.

It does use a e67 CPU which some tuners don't like as well as much as some of the newer CPUs, but it hasn't been a problem.

[Blevinator]

PSI Conversions harness here. $549 and well made. Call PSI and ask them about the GMPP.
The PSI harness can be ordered lengthened to locate your ECM behind the dash. It incorporates a 3 wire hookup to the car.

[XLexusTech]

+1 I went with PSI AND I could not be Happier..

PSI Conversions harness here. $549 and well made. Call PSI and ask them about the GMPP.
The PSI harness can be ordered lengthened to locate your ECM behind the dash. It incorporates a 3 wire hookup to the car.

[67CamNKC]

I ordered mine from PSI last week and had it in a few days. Nice quality and good instructions. I ordered mine with computer and tune. Drilled the firewall hole today and started laying out the harness. No need to order the harness with extra length, as I have extra already. Putting my computer behind the glove box in my 67 camaro. Hope to start mine pretty soon.

[Evldoer]

Glad you guys had good luck with PSI because I didn't. I got a harness from them. I called with a few questions and they helped me out. Then I took my car to the tuner and we couldn't get a reading on the O2 sensors. Spent a couple hours trouble shooting and figured out the O2 wires on the harnesses on both banks were switched around. We re-pinned the connectors the right way and still couldn't get the O2 sensors to read anything. Ended up buying a new pair of sensors and it was good to go. So the harness had the 12 volt heater wires pinned to the signal wires on the o2 sensor and burned them out.
I called PSI and left a message on what happened and they never got back to me. Cost me a couple hours labor at the tuner and an extra 2 oxygen sensors. So yeah, no more PSI harnesses for me. And yes, I do feel better now

[67CamNKC]

My computer mount bracket was broken in shipping. I didn't like how PSI handled that, but the harness looks nice. I will let you know how it goes when I fire it up.

[parsonsj]

I'm a big fan of the GMPP harness and controller too. Good prices, OEM quality, and works perfectly.

Now... the LS9 harness --- that's another story.