Frank TheTank

My new build is a stock cube ls1 built Callie rods mahle pistons all balanced custom grind turbo cam ported heads flow 300cfm with fast 92 / 92 ported huron speed V2 t4 non a \ c kit with s476 billet 4in bumper exit downpipe gforce t56 spec super twin disc anyways to my prob. My old build was a stock motor ls1 with a sts rear mount setup well finally got to start her up today ND wasn't happy the car didn't sound like it ahould have wants to idle super high sounds like a 6cyl wen we started to turn the throttle body blade screw to get the idle down and wen we started car start backfiring loud my tuner went thru my ecu n just did a basic start up tune for this as he built the motor I figured it would run a lil rough buy not like this any help would be great I'm at a loss on this and kinda disappointed for my first start thought having 15k in this build and still more to spend it's just keeps throwing me a curve ball. And anyone have any tips or ways to make this right I thought have the 4in bumper exit downpipe the car would sound sick but didn't know wat to except I got a vid of the start up

Plzs help
Thanks for reading.
Frank

Bob@BruteSpeed

iTrader: (16)

Sounds like you might have a bad vacuum leak. Bob

FASTFB

iTrader: (24)

Have your tuner log the start up and that should tell you everything you need to know. Need to know your AFR and what was vacuum? A person is also going to need to see the tune file. How about injectors ( same as old build ? ) lots of variables. I see you are from ND. Where are you located?

asubennett

iTrader: (6)

Coil harness flipped around? Both grounds for coils grounded?

Frank TheTank

Located in St louis mo. And same injectors as old build just for break In and the coil harness being flipped make that big of a deal I didn't pay attention wen putting them back on thought they were the same.
N yea I thought vacuum also idk tho all the lines r on n hooked up could it be the intake gaskets art sealing right I used the ones they came with its used came of a buddys car that ran great I'm just lost at this point

Frank TheTank

Prob found damn coil harness was on backwards lol alway somthing stupid

JustAFooL

iTrader: (45)

You might get more suggestions if you used a period or comma here and there. I got a headache trying to read that ****.

Glad you found your problem though, I did the same thing once after doing a H/C swap. Easily done.

asubennett

iTrader: (6)

Good deal. I put labels on mine so I don't mix them up anymore.

DETROIT_AREA_00_SS

iTrader: (7)