just had new header and exhaust installed, however now im getting misfire in the power band, (low rpm light throttle is fine and WOT is fine, just not mid throttle highway driving)
from what im thinking is i dont have enough back pressure and/or too much flow to the back o2 sensor.
also after the install my traction control off light came on.
im thinking i might just have to have a exhaust shop properly install the exhaust as it took me and a friend 10 hours just to get this one mounted as the stupid ebay headers had alot of clearance issues.
anyone have any other ideas.
Ive used a pacesetter header with 3in down pipe with cat delete and a casper electronics rear o2 simulator and have never had a problem with misfire at mid rpm.... You may want to try and find a simulator if you are running a cat delete.... if not i would look for header leaks at the gasket or a leak at the flange as this will cause this to happen due to the o2 thinking it needs more fuel
Erik Packard
That may be what i have to do. although im wondering if there is a cheap solution to test that theory. (someway of feeding a false o2 reading cheaply , i have some electronic experience along with alot of parts i can usually make things out of including a micro controller.)
btw avoid this header/pipe
http://www.ebay.com/itm/Chevy-Cavalier-Pontiac-Sunfire-96-01-2-2L-Exhaust-Manifold-Performance-Header-/230996751748
There are so many fitment issues. 1 header hit ac compressor requiring making a small dent in one tube. 2 where the pipe connects it is a tight fit and it is hard to get a good seal. 3 pipe hits trans pan edge. 4. pipe not aligned right and exits at angle. 5 o2 sensor bung is on wrong side and o2 sensor will hit frame, 6. water hose is really close, requires a little bending to give clearance. 7 oil dipstick tube hits headers and required a bit of bending.
so this exhaust was a pain in a butt, although thats what i get for 90$ on ebay.
also i need to find a quick and easy way to make the exhaust not as loud as to get a cop to sign off on a fix it ticket. (old exhaust was about as bad but leaked in front, this just makes more noise out the muffler now.
^^rear o2 does nothing and won't do anything to make it run differently. If its not there the only thing that will happen is the cel will light up.
Also the 96-97 heads were different then 98+ so i know its bad news depending of the year of your car it could be the wrong header in general if its a 97- the header flange ports will actually be smaller and more restrictive then even stock
Erik Packard
i keep forgetting to say what car im using,
2000 cavalier 2door with the 2.2 ohv gas motor.
My guess is that it's leaking both at the knuckle and the flange to the head. I know because I had an ebay header for the same car/motor and that's what it did.
The flange wasn't even close to flat. If you take it off again; lay in on a bench and put a straight edge across the flange to confirm. I had to belt sand the @$#! out of mine to get it flat enough for install. I also had to clearance some of the bolt holes so I'm assuming you got the same one I did.
"In Oldskool we trust"
Do you have a check engine light? Most of the time with the aftermarket 2200 headers your upstream O2 will have trouble getting heated up since the new location is so far down the pipe compared to the original.
That can cause driveability issues because the car is over/under fueling.
I believe theres a heated O2 sensor install write up on the first page of the Performance section right now. Check it out.
Brian wrote:Do you have a check engine light? Most of the time with the aftermarket 2200 headers your upstream O2 will have trouble getting heated up since the new location is so far down the pipe compared to the original.
That can cause driveability issues because the car is over/under fueling.
I believe theres a heated O2 sensor install write up on the first page of the Performance section right now. Check it out.
Spot on. I completely forgot but I also had to convert to a 4 wire(heated) o2 sensor when I did that upgrade on my 01. What I said about the flange still stands though.
"In Oldskool we trust"
Not getting any leaks at the flange or knuckle but im almost betting that the front o2 sensor is bad (when we took it out of the manifold it looked like it got real hot one time and started to melt.) however i ran out of money so replacing the sensors is almost impossible even with my next paycheck.
however i didnt get any misfires on the way to work today, but im still running very rich and its looking like im getting only 15mpg based on how fast im going through gas.
also i got a new symptom, now i have no torque converter lockup (my rpms where a little higher than normal and i never felt the lockup kick in like normal)
basically im down to this, is there any way to force the car not to dump so much fuel till i can get it fixed properly? i do 500miles a week to goto work and back and i dont think this thing will last a whole month like this.
