fivepointseven

iTrader: (19)

Ok, my MACS are on and they are LOUD. Almost too loud! I have no cats, do people people use their cats on a aftermarket header install? (BTW, I also have a cut-out, should I cap it off?)

Also, I am misfiring, o2 problems, and a knock sensor.. What should I do? Will predator tuner fix this?

Thanks

ApacheDrill

iTrader: (21)

well cats or no cats is on you, if your not running cats run a ORP, what the rest of the exhaust like as far as cat back etc..? As far as caping the cutout, if you need it open, open it, if not close it..Again thats up to you. The mac's shouldnt be to bad but expect atleast a little rasp..

fivepointseven

iTrader: (19)

Well, the O2s are hooked up but Im still getting the service engine light. Any idea of the problem?

ApacheDrill

iTrader: (21)

your running all 4 or you deleted the rears?

fivepointseven

iTrader: (19)

all 4

fivepointseven

iTrader: (19)

...but without cats. Im guessing o2 sims are what is needed. Are they easy to install? Should this fix my problem?

Sorry for all the question, Im a newb

ta981

iTrader: (10)

This link should answer some of your ?'s.....
https://ls1tech.com/forums/showthread.php?t=139142

Kurt D

iTrader: (2)

Yes sim's will solve your rear o2 codes. They plug and play, tie them out of the way.

Cap your cut out if it's too loud.

People do sometimes have knock and/or missfire issues after header installs. Make sure everything is connected correctly, no leaks, etc. The PCM needs to relearn everything. You can reset your PCM if you wish, www.installuniversity.com has instructions, to accelerate this. After a few miles everything should work out.

USMARINE1108

iTrader: (2)

I bought my Preditor thinking I could delete the rear 02's, but after I put my Mac's and ORY on and talking to dioblosport, you can't. You'll need to get a new tune from Diablosport if you want to use the Preditor to do it, but I said screw that. Just get a good dyno tune and have the 02's deleted. Or 02 sims will do it, too. What codes are you getting with the SES light? I got "Catalist system blank below threshold", or some crap like that. It's just because the cat's arent there. No biggie. Totaly normal for that to happen, it's suppsDo you have an aftermarket catback?

Swang

iTrader: (3)

what cat back are you running?

fivepointseven

iTrader: (19)

my exhaust is stock save for cut-out and now headers

USMARINE1108

iTrader: (2)

It shouldn't be very loud with the cutout closed. If it is, check for leaks. I'd start with the bolts on the headers, then work your way back. Remember on those ball joints, tighter isn't always better. I took mine to an exhaust shop and just had all of the connections welded. Hope this helps you out.

fivepointseven

iTrader: (19)

Im taking it to an exhaust shop tomorrow to weld the y-pipe so Ill get them to check it out.

Thanks everyone for the help!

ss rally red

iTrader: (8)

If you are 'misfiring', is that code present? And ALL you did was install Mac's,then the only cause for a misfire code would be if you dont have all the plug wires installed correctly at either the plugs or the coil packs. Or you cracked the porcelin on one of the plugs upon install.

fivepointseven

iTrader: (19)

Yeah, it broken on install. I bought new ones today and they are a bitch to install!

ApacheDrill

iTrader: (21)

Well atleast you tracked it down..have fun