Standalone vs. GMPP Engine Harnesses
 

I searched for this so if it has already been covered I apologize.

I will be running a crate LS3 with a T56 in my 69 Camaro. I do plan to mount the engine controller/fuse panel/relays behind the dash if at all possible as I don't really want to have much wiring exposed under the hood.

Is the GMPP harness feasible for this application or am I better served going for a standalone harness from one of the vendors?

I also intend to use an AAW update main harness. Does anyone have information on how to interface these two harnesses? Which harnesses control what etc. Any diagrams would be great.

Thanks in advance!

GMPP stand alone controller is $955 on GMPerformancemotor.com Parts #19201861
Its says for everything you need to run an LS3.

http://www.gmperformancemotor.com/parts/19201861.html

It's a great value considering what you get.

Converting your used harness is $700
ECU is $200
Flash and reconfigure is $350

I remember reading that the GM Performance ECU's cannot be reprogrammed, can anyone confirm this?


edit.... supercedes to 19258270 and yes it can be tuned via HP tuners.

Harness
 

Going LS7, have just started installing the custom harness from PSI and GM 58X ECU and DBW pedal and I can tell you the quality is excellent and so is the price.
I am also using the AAW harness in my 69'

Manny at Dasilva Motorsports is going to get it going and tune it on the dyno

I am most definitely not great at electrical, but it seems very self explanatory thus far, and the instructions are excellent as well

Steve

Just remember that "one size fits all" really fits no one.

If you want to be able to hide all the wiring etc - you will need to be able to skillfully pull various connectors apart and trim the wires etc. You may need to split certain "runs" of wires out of a main harness in order to hide them.

None of it is rocket science - but it will require some special tools. These connectors (Weathercock and Metripack etc) have their own styles of "males and females" and you'll need a supply of them as well as the tools to disassemble the connectors and crimp on the connectors. Delphi and others make the tools you'll need.

There's plenty of videos on YouTube that will show you how to do these.

Buying a GM standalone system and hooking it up and getting everything to work could be done by a 5 year old.... it's when you're trying to make it LOOK nice by hiding things is when it take A LOT more work and some skill.

Ironworks (a vendor here) makes brackets to hold the ECU and makes that easy to mount...

You're going to have to plan out where you intend to mount that --- and where you're going thru the firewall etc. Sounds like you haven't done this before so you need to think about the order of things. You'll also need to be able to fab up a mount for the DBW pedal etc.

True...we have done a handful of GM "Connect and Cruise" harnesses and the relay box is HUGE. If it is an automatic they give you two controllers to stash AND as Greg says I end up pulling the harness apart to make everything land where I want. YES even the tune is not great. They can be and should be tuned. The drivability and power can be increased.

PSI harness pedal and computer work well for us and we LOVE the Holley kit. Harness is already wrapped nice and offers lots of ability to tune. - Chris

Thanks for the replies guys. Not new to wiring just new to pro touring type builds and working with factory style weatherpak connectors. I have studied all the pin outs and even considered just making my own standalone since there will most likely be several runs that are custom length.

I should have studied the AAW schematic before I even posted this because I now see how it easy it is to get everything interfaced between the LS harness and the AAW harness.

I will be using Ironworks moount for the ECU, I just have to wait until I get the vintage air unit mocked up first to see what my clearances look like.

I also planned to use Ironworks DBW pedal mount as well so that I don't have to custom fab something.

As far as the canned tune goes I will just be using it for initial start. After that it will be going to Futral Motorsports. They do all the work on my 2011 Camaro. I actually am not a fan of remote tuning/canned tunes and prefer to pay for dyno tuning. That crate LS3 is most likely going to turn into a cammed/magnacharged setup anyway.

As mentioned, the GMPP harness will have a lot of extra length. We spend 4-5 days cutting the GMPP harness down to make it look really nice for my '69 Camaro coupe. All of my other cars use a Speartech custom harness. They're worth every penny. They're built for whatever setup you want and can run your auto trans in most cases. No trimming to mess with, and they will also supply the ECM. However, you'll still have to get it tuned. FYI, the GMPP ECM can be programmed no problem. For any of the N/A setups, mail-order tunes are very easy to do. We average 15-20 each week, and it can save you some money if you don't want to mess with a dyno tune.

Let us know if we can help.

Trevor
Texas Speed & Performance

Holy crap I've been selling them for like $400! Looks I need to jack the prices.