suprjet2

I had AR headers installed with stock exhaust and a k&n filter and now it runs rough at any steady RPM. I have replaced the spark plugs and wires and it still does it. I took it too a local well know tuner and he richen it ,leaned it , retarded timing, open loop, closed loop, and matter what I do can't get rid of surging, nugging, skipping feeling went I'm criusing at a steady RPM and its at all RPMS. So I put the stock filter on and wires back on didn't help. So I took it too the local dealer and they said there were no codes so it must be the headers and I knew they were going to say that. Does anyone have any ideas on what is causing this? Could o2 sensors they installed be connected wrong?

Keith

P.S. One good thing while on the dyno he was able get 485 hp 455 torqe

Turbooo2u

I had the AR headers installed at Carlisle but I have a few more MODs than you. (see sig. below). I seem to have a slight surge, tug, at higher gears in lower RPMs. Give Nick at AR a call and see if he can't help you out. Good luck!

J HEBERT

This really sounds like a leak ahead of the front o2s.....even just 1 side will do this. U need to scan to verify, or, grab a length of hose and put 1 end to your ear and pass the other end around each exh.port at the head on both sides while running. Did u use the steel shim gaskets or what?

Jorday

I was just thinking that same thing when I read his post. When it happened on my Z28 it ran terribly.

tjwong

If its a leak in front of the o2s which is hard to beleive due to the design of the connection to the X pipe. It would be easy to diagnois. Have the dealer tech use his TECH2 scan tool, drive the car and monitor the long term fuel trims, if its leaking he should see the fuel trims skew positive a considerable amount, the reason is that the raw air leaking into the exhaust stream will be seen as a lean condition and the PCM will adjust for this. Also have him monitor spark retard, as you may have some mechanical interference causing noise that the knock sensor is hearing, and is causing the PCM to retard timing.

suprjet2

Thanks everyone for your help.

Tonight I will check for leaks.
I do remember and wondered why when monitoring the long term fuel trims why one bank read different than the other for example:
bank 1 -4.xx bank 2 -6.xx when cruising. Would this mean bank 1 has a leak?

Thanks again for all your help.

Keith

GrillnZ

Either way get those LTFTs to near 0 at cruise! Good luck!

Cape Cod Bob

There is an easy path to the problem and the solution.
Unfortunately the gentleman who I would have solve this is not a sponsor of this forum so I don't think I can publish his site.

He's my go-to guy, if I had a problem like this.

Bob

427Z

so whats the solution, what would your guy do about it?

El Puto

Sorry to hear about your problem, but its a good thread to let others know that headers can suck and be a PITA. Unless you have an aggressive cam or high boost FI, I see no good reason to get headers - period. 485 rwhp can be had with CAI, intake port job and good tune. I'd bet your headers got you nothing or next to nothing - except a headache and a car that's not as fun to drive.

The solution, as one poster posed, is to go back to stock manifolds.

Zix

Nope, if you had a leak you would be seeing positive fuel trim numbers, not negative numbers.

02gt350

not sure how the Z is set up, but after my long tubes, i deleted the rear o2's. did they delete them out in the tune? or another known problem is switchin the o2's around. drivers side has to be drivers side ect....

Zix

I would think it would be throwing a ton of codes if the rear O2's hadn't been deleted yet, or sims put in

RGT

I am guessing that you don't have headers. Stock or modified, headers will give you an increase in mid-range torque.

UTVOL06

Headers will gain you power..mostly torque in the low-mid range. If you have a ported intake, headwork, or cam you will benefit evem more from headers.

augydog

Could o2 sensors they installed be connected wrong?

This could be it, although it seems it would be throwing some codes.

What header gaskets did you use, factory metal ones?

Headers alone should not cause what you are experiencing.

I had Kooks headers installed on my C5 Z06 before I had a tune and without any other mods, and the car ran perfect. No surging, smooth idle, etc.

Also, at the time you installed the CAI, did you notice any oil in the stock intake or throttle body? Wonder if your MAF sensor has some oil on it?
If it does, this could cause what you are experiencing.

AR headers are good quality headers.

Let us know what you find.

augydog

augydog

Your right about headers being a PITA, but only if their installed incorrectly. In other words, necessary engine parts not removed before install, 02 sensors installed improperly, no heat protection + poor routing for the wires, flimsy aftermarket gaskets at the flanges, everything not buttoned up properly, and no re-check of bolts after a heat cycle.

Headers will make the exhausts sound the way they should sound from the factory, also the torque can be felt.

Headers done right, are a joy to behold.

augydog

0Myhardtop

Go back to stock manifolds...What?

At the track if everything being equal [driver, tires and etc], a headers & X-pipe equipped Z06 w/tune will beat a NON headers equipped Z06w/tune EVERY TIME!!!

We have done many headers install and never experienced any drivability issues with the ARH. It's simple, the ARH units are well built and they make power.

Thanks,
Carlos

If your goal is to make 500rwhp, then you will NEED headers period!

Luweegy

The secondary O2 sensors don't matter side to side cause they are after the X in the pipe.I don't use mine and shut them off cause I did'nt want wiring issues.I used factory steel gaskets no problem.Watch your oil cooler lines,they can be trouble.

El Puto

Oh yeah?

http://forums.corvetteforum.com/show....php?t=1813242