hello, Im new to this and not too good with a computer. I am a carb guy getting into fuel injection, ls2 into an offroad race "jeep". I have read up on the engine choices and understand most of the quirks...gen3...gen4..etc. here is my question, GMPP sells an engine controller ecm, drive by wire and harness for the ls2 crate engine for @ $800.00. other places want substantially more such as speartec, current performance...... My use is in an offroad only application with t350 tranny so no trans. controller needed. I also am a firm believer in "You get what you pay for". This will be a gen IV, so apples to apples why the price difference in GMPP compared to others? are the connectors different? This will be used in a dirty, dusty somewhat wet and muddy environment so connector quality may be and issue. Any help in this choice would be appreciated... Thanks from Washington State....Jon

 

GMPP is similar to OEM, it does have its quirks, but what makes it a value is that it does come with extras such as the ECM, underhood fuse box, DBW throttle pedal, O2 sensors and mass air. The connectors are the same as you would find on any late model GM, weather resistant, etc. The thing that is a turnoff is you cannot specify specific underhood wiring lengths; all the harnesses appear the same design, and as such things like the MAF and coolant sensor have unnecessary generic lengths. Another possible hangup, is that the harnesses are more Gen IV specific, as in relocated cam sensor, map sensor, and different injector connectors and different crank/cam reluctor wheels (on later LS2, LS3/LS7).

Speartech has similar offerings, although his harnesses are more of a true-fit setup using real world dimensions. You can save a little by utilizing a converted donor harness that matches your engine style generation, especially so if you already own the stock harness. I would consider Speartech to be more custom taylored, while some others are one-size-fits-all.

There are a few other companies, some advertise here, and some do not. Usually the best reside in this forum.

 

The main difference is that the GM harness is made from a "1 size fits all" template, and the other guys are making them custom.
Also, the GM harnesses are made in Mexico or Canada, so labor is much cheaper, therefore, they can easily produce a cheaper harness.
I doubt there is any difference in quality, just quantity.

 

Should be a pretty easy chore to shorten harness wires. You can get new pins from any number of sources.

 

Thanks for your replies. I am building an Ls2 "clone". It's an '03 lq4 6.0Liter block, accessories, oil pan.....but with '06 Ls2 rotating assembly ,heads and intake. I realize the problems of the intake and truck accessory drive and the mods I will have to do to the water pump. In short, I am attempting to make a genIV out of a genIII. I know the cam sensor, crank reluctor and map are different but I also heard the alternators are different and need to be swapped to an genIV alternator to work with the GMPP genIV controller. The reason for this is : I can buy the GMPP controller @$800.00 that only works with genIV, and change the respective sensors to make my engine a genIV cheaper than keeping my engine a genIII and going with an aftermarket controller @$1400-1500.00.....because GMPP does not make a controller for genIII (not that I have found) Any comments or suggestions are appreciated, Jon

 

I went with Speartech for my wiring harness and PCM reprogramming. They do great work and the best thing is if you have questions, you can actually speak to John on the phone. In this day of hearing "Your call is important to us, please hold, you're caller number 947" and then getting someone who doesn't know squat, the ability to get my questions answered promptly was worth the (small) extra price.

 

I can 'second the notion' on being able to talk to someone like 7T3LS1 said. John (at Speartech) is willing to help if you call and if its something he built or modified for you, he WILL know the answer and provide you with direction.

 

Given you dont need to control an auto trans, echoing what other posters have said, the GMPP kit is excellent value.

As Joseph mentioned, it does have its quirks.

They do have their challenges at times, but these are not difficult to overcome. Several we have been involved with had wiring/pin out errors. Pins in wrong places in connectors. And not just one. While this shouldnt damage sensors, we have one customer that is chasing some odd fault problems because of this.

As one poster said, they are most likely made in Mexico where a lot of GM wiring comes from (Camaro for example), but may also be made in Western Samoa or Indonesia as well. So actual build labour content is $10-$20 in terms of what a worker gets paid for between 1 and 2 days work. Thats why the harness is cheap. And packaging everything in one kit to handle means GM parts costs for the O2's, MAF, Pedal, etc really dive. Manfacturing costs on average are 1/10th of list or below, so it is the handling of items that raises parts costs.

The controller tune is something of an odd ball too. Some people have trouble with them. But like anything, you only ever hear of the problems. They dont support a TCM in their native form.

Which is why someone like Speartech, or a similar harness shop, adds a lot of value. They custom build a harness for you and your retrofit. Hand made with love by enthusiasts, and not one of 10's or 100's of thousands churned out at a price. Tried and tested auto and manual ECM/TCM combinations. Different engine types. A lot of retrofit and even racing experience AND friendly support on the end of the phone as Cutlass and 7T3 point out.

Yes you can call GMPP tech line, but once you have gone away from a stock tune on the standard GMPP controller.....or anything is different.