GMPP LS3/430 Controller kit
Thread Starter
Staging Lane
Joined: Dec 2017
Posts: 95
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GMPP LS3/430 Controller kit Hi all,
I'm in between and questioning which engine wiring harness I should buy. I'm swapping a crate Ls3 into my Honda S2000, and am looking at the GM controller kit verse a built custom dual ecu wiring harness due to a few reason's. I am concerned how far it will reach or at all into my cabin (Will I have to cut/splice and add wiring). I'm sure someone here has some insight into the controller kit and overall craftsmanship/quality. I keep finding bad reviews on the custom "dual ecu" wiring harness's from Tweak'd Performance, plus in comparison for the same price the controller kit comes with way more, including PCM, Pedal, o2s, MAF, MAF boss etc.
Any insight to GMPP controller kit is appreciated. How do they hold up? reliability? were you able to locate/secure the PCM in the cabin? It seems the kit is a "universal" harness, how much extra length, or wiring for different application's/platforms does it suit? maybe an overall length in "xx" from the rear of the drivers cylinder head that someone could say?
OR; has anyone recently received a "tweak'd" 58xx DBW dual ecu harness? Has the quality assurance and control differed, were you pleased with the product outcome?
I do not want to locate/secure a rats nest in the engine bay, clean install would be worth my while but also little to no splicing/hacking...
I'm in between and questioning which engine wiring harness I should buy. I'm swapping a crate Ls3 into my Honda S2000, and am looking at the GM controller kit verse a built custom dual ecu wiring harness due to a few reason's. I am concerned how far it will reach or at all into my cabin (Will I have to cut/splice and add wiring). I'm sure someone here has some insight into the controller kit and overall craftsmanship/quality. I keep finding bad reviews on the custom "dual ecu" wiring harness's from Tweak'd Performance, plus in comparison for the same price the controller kit comes with way more, including PCM, Pedal, o2s, MAF, MAF boss etc.
Any insight to GMPP controller kit is appreciated. How do they hold up? reliability? were you able to locate/secure the PCM in the cabin? It seems the kit is a "universal" harness, how much extra length, or wiring for different application's/platforms does it suit? maybe an overall length in "xx" from the rear of the drivers cylinder head that someone could say?
OR; has anyone recently received a "tweak'd" 58xx DBW dual ecu harness? Has the quality assurance and control differed, were you pleased with the product outcome?
I do not want to locate/secure a rats nest in the engine bay, clean install would be worth my while but also little to no splicing/hacking...
Staging Lane
Joined: Dec 2015
Posts: 96
Likes: 0
The GMPP harness is a very good harness and prob the cheapest. I see no reason at all it wouldn't be long enough to fit in the cabin. I have the GMPP harness in my 69 Camaro and it will reach just shy of the battery tray up front by the passenger fender well.
Thread Starter
Staging Lane
Joined: Dec 2017
Posts: 95
Likes: 0
It has its own fan, and fuel pump relay correct? Im assuming it does, I just don't want to be surprised, or pissed off for not asking something simple.
PSI Conversions seems to have practically the same kit! (from GMPP) for sale for about $50-$100 less, and they also advertise "Harnesses are designed with a sliding grommet seal and 4 - 5 feet of length from the rear of the cylinder head to the PCM mounting position under the vehicle dashboard." (which im sure would be enough to accommodate)
I'm wondering if this is a "clone" of the GMPP or they are mimicking the GMPP "universal" kits with an additional 4-5 feet to mount in cabin.
I have read extensively on this swap and it seems odd to me; why tweak'd "dual ecu" harness is so expensive, for only the harness, on top of the fact that, I have read you could even still run signals to the stock dash via modrify coolant healer and speed healers like the Dakota digital etc. via a GM harness and GM VSS. I just hope Im not "making" excuses to buy the cheaper route installation. Im sure its a great product, I just want to make sure I understand what Im getting into by going a certain direction with the powertrain management.
Thanks for your time!
PSI Conversions seems to have practically the same kit! (from GMPP) for sale for about $50-$100 less, and they also advertise "Harnesses are designed with a sliding grommet seal and 4 - 5 feet of length from the rear of the cylinder head to the PCM mounting position under the vehicle dashboard." (which im sure would be enough to accommodate)
I'm wondering if this is a "clone" of the GMPP or they are mimicking the GMPP "universal" kits with an additional 4-5 feet to mount in cabin.
I have read extensively on this swap and it seems odd to me; why tweak'd "dual ecu" harness is so expensive, for only the harness, on top of the fact that, I have read you could even still run signals to the stock dash via modrify coolant healer and speed healers like the Dakota digital etc. via a GM harness and GM VSS. I just hope Im not "making" excuses to buy the cheaper route installation. Im sure its a great product, I just want to make sure I understand what Im getting into by going a certain direction with the powertrain management.
Thanks for your time!
I have used several of the GMPP harnesses. They are not really designed to enter the cab, as the layout is wrong in my opinion. They are actually 3 separate harnesses connected together at some point. If you have the room in the engine bay, you can hide most of it....good harness, works very well and comes complete...fuse box is huge though....
PSI does not mimic this harness in any way. I have also used several of these and prefer them and BP automotive to the GMPP unit. Both have a single pigtail that can go into the cab and mount under the dash. Both come with all the components ready to go. I suppose you could have them build you a longer pigtail if needed...
Not sure what you are referring to with a "dual ECU". You have the ECM, and a trans controller, pedal and fuse box, that's about it...
T,
PSI does not mimic this harness in any way. I have also used several of these and prefer them and BP automotive to the GMPP unit. Both have a single pigtail that can go into the cab and mount under the dash. Both come with all the components ready to go. I suppose you could have them build you a longer pigtail if needed...
Not sure what you are referring to with a "dual ECU". You have the ECM, and a trans controller, pedal and fuse box, that's about it...
T,
Thread Starter
Staging Lane
Joined: Dec 2017
Posts: 95
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Hey, thanks! Thats really good info. Exactly what I was looking for.
Im gonna email tweak’d cause I am curious what all im getting by going with them or not, cause what im tracking is it runs both my stock ecu for my stock dash and the gm ecu for the engine. So im debating if its worth just splicing in everything for gauges off a psi,gmpp (equivalent) or tweakd dual ecu harness.
Im gonna email tweak’d cause I am curious what all im getting by going with them or not, cause what im tracking is it runs both my stock ecu for my stock dash and the gm ecu for the engine. So im debating if its worth just splicing in everything for gauges off a psi,gmpp (equivalent) or tweakd dual ecu harness.
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Staging Lane
Joined: Dec 2017
Posts: 95
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Hmm, ill have to look that up. The stock instrument cluster is CAN serial gauges. I more or less messaged to tweak’d to sell me on their harness and see whats up. Cause either way no matter what nothing is plug n play so why go with theirs or another above any?
On The Tree
Joined: May 2010
Posts: 159
Likes: 1
By looking at this diagram, it looks like theirs can communicate with the Honda's CAN system, to talk the gauges, speedometer, etc. That looks like a good deal to me. PSI and GMPP controllers are stand alone and you have to find your own way to control the gauges and speedometer on your stock speedometer and gauges.
I have the GMPP kit in my camaro. While it is a good kit and I haven't had any issues with it, one thing that I wished it had was 2 fan outputs. Yes, you can add a kit from PCMofNC but in the end you pay another $100 to have a second fan. If you are running a T-56 and want to utilize the reverse lockout feature, you also have to add that yourself. Not difficult but I believe they are already part of the other harnesses. I bought mine back in 2009, if I did it now, I would opt for a PSI or Speartech one.
I used a new crate LS3 in mine -- and PSI Conversions supplied 08 Corvette ECU (manual trans) with custom harness, and matching mass air sensor, O2 sensors and gas pedal. Removed rear O2 sensor and evap/purge valve function and VATS from the computer. Car started on the first turn of the key and has run flawlessly since. Great customer support from PSI all along the way.
Thread Starter
Staging Lane
Joined: Dec 2017
Posts: 95
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great news! I went with a tweakd custom harness due to me wanting all the oem gauges and support for speedo and electronic power steering but I did go with a PSI E38/pedal/o2's etc Im hoping for a good first turn key start to. How did you prime your crate engine for the first time if you don't mind me asking? Thanks! The Pdf files for Chevys crate engines says to get this super expensive oil primer and I just cant justify buying it for one engine atm. figured just pull the plugs, kill the fuel pump and crank it over till I see oil in the top end.
There’s a port low on driver’s side front right behind where a low mount alternator would go. 16 x 1.5 -6AN fitting there and simply connected my Motive brake bleeder. Put a couple qts. into the container and pumped it up to 10-15 psig. Kept going at that until I got some oil on the dipstick - probably 4-5 qts in that way. Rotated crank with pulley bolt a few times while it was filling. Put plug back and topped up til dipstick showed full. Made a second or two of lifter noise then quieted right down.
Thread Starter
Staging Lane
Joined: Dec 2017
Posts: 95
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That sounds do able! Did you have to buy separate adapters to hook your bleeder up to the block?
Like that fitting your talking about; was the other end just a small barb hooked up to the bleeder hose?
did it come with your bleeder kit?
Like that fitting your talking about; was the other end just a small barb hooked up to the bleeder hose?
did it come with your bleeder kit?
The Motive bleeder is something anyone who changes brake fluid should own. Other than the fitting I screwed into block (Jegs) I had the clear tubing and 6AN fittings I needed. I would not turn over a dry brand new crate motor....fwiw.