I'm having some rough idling issues after LS3 swapping my 370z. My diagnostic scanner says all 8 cylinders are misfiring.
This is what I have installed:
The engine came from sikky and the LS3 6.2 liter crate engine is beefed up by them. This is what is on the website for the engine I ordered:
N/A – 416 ci LS3 based aluminum block Peak Horsepower: 598 whp @ 5900 rpm (rated at the wheels) Peak Torque: 575 lb/ft @ 5050 rpm (rated at the wheels) Compression Ratio: 11.6:1 Required Fuel: 91+ Octane Pump Gasoline Forged Pistons – 4.070 Bore, 4.0 Stroke Forged Steel Crank 1500hp Rated Forged 6.125″ Connecting Rods Sikky/AFR Cylinder Heads Comp Cams Camshaft 235/251, 621@113 LSA Upgraded Trunnions LS7 Lifters Pro Series .080 4130 Chromoly Pushrods Melling Performance Oil Pump GM Performance Assembly Components *All hp numbers will be within 2% of the advertised number* Sikky Manufacturing hand built LS engines feature the best components and are assembled by professional machinists. All hand built engines feature a balanced and blueprinted block with forged internals. We also partnered with AFR (Air Flow Research) to equip these engines with CNC cylinder heads. These builds have been track tested for maximum reliability and performance. *Horsepower numbers are at the wheels on a Dynapack dyno with stock LS3 intake manifold and throttle body, Sikky 1 7/8” headers, and Sikky 4” intake/filter*
I also ordered a t56 transmission, drive shaft, and wiring harness through sikky.
When I contacted wiring specialties who is who sikky went through for the harness I got a e38 computer from them. My diagnostic scanner says the ECU is a 2010 GMC Yukon 5 3L. Their website says that the ECU is flashed for start-up only and is designed to allow the engine to start without vats and emission fault protocols. I installed everything myself if I know means am I no mechanic but I just spent almost 30 something thousand dollars on all this and all I want to do is drive my car all this started in February we're now in the middle of July almost and I just could really use some help getting this thing running please. Thank you

 

You should be getting top shelf support from the vendor if you went all in and basically bought a package.
You may end up seeing if they have a installer locally that you could go to just to have them scan the system.

If you have not had it tuned yet ,, well yea its not going to run right with the spec parts you listed. and a
cheap scanner is not going to do it. It needs HP tuners or similar and a experienced tuner to get it dialed in.

Most common reason for all 8 cylinders to misfire is you didn't ground the coil packs to the ground points
on the back of each head, or just grounding in general, my basic experience on LS engines is grounds MATTER a lot.
Most cars I've helped on that were tuned correctly but had run-ability issues it was a bad or missing ground.

 

Thanks, I agree I should be getting top notch support. They leave a little something to be desired. I'll try again Monday. So the flash on the ECU to "start" is that a temporary tune? So I'm no mechanic I've done an engine swap before on my Dodge ram but what I pulled out I put the exact same motor back in it was real easy this is a whole different animal all together. Yeah I've been rather disappointed in the vendors support. So they didn't even tell me that the coolant plugs weren't in the block I found that out when I was adding the coolant, it just started dumping out of the passenger side of the motor from 2 spots. After the coolant incident I messaged them and let him know and there was like No remorse whatsoever about that. And I'd let them know I'd never messed with ls engines before and you know when they sent it to me a lot of the sensors were in already the fuel rails were on and so I figured they did what needed to be done to the engine block now I probably need to go back and check everything I'm tired of pulling this engine out of here.