Whats up i just finished installing my Hooker Headers and Y pipe onto my L03 and its running really strange. I bought new wires and custom made all the plugs. After firing it up I noticed it was stuttering and almost choking when you get on the gas. I sawed off the AIR system(?) that runs from the cat to the smog pump and left the smog **** off. I found that i cracked 2 spark plugs and i replaced them and at first thought it fixed the problem but it didnt.. Maybe i bumped the distributer out of whack when i changed the plugs(late now cant check)? But the weird thing is it only starts running shitty when the car and exhaust warms up.. Was I not supposed to delete the little metal line and hose that runs from the cat up(thought it was emissions)? Its also not arching which is why I'm sure its not any of the wires. I ran WinALDL and didnt see any error codes besides the oxygen sensor but it was reading .459 O2. I did drill the hole and tightened the sensor in good.. Any suggestions?

 

I couldnt tell you for sure that this would cause that, but you really need to get a chip made for you unless you want to do it yourself.

The Speed Density systems have certain assumptions they make about how well the car breathes, and if you change the exhaust out that much, then the computers assumptions are going to just be entirely wrong.

Also, you probably shouldnt have yanked the cat and such, but since you have, you might want to just get rid of all of it and get a chip made that knows you got the emissions stuff deleted. You can get rid of all the emissions stuff but it's important to do it right.

Anyway, it's nothing unfixable, you just need to finish the job.


Also, Im no expert about any of this stuff, but Im pretty sure hte major change from the car running open loop (when the coolant is cold) to closed loop (when the car warms up) is the computer starts to use the input from the oxygen sensor. I think in closed loop the computer just works off those same basic assumptions I was talking about. So you may well have some sort of oxygen sensor problem.

 

I never knew changing the headers did that much to make the ecm out of whack. I have all my tuning stuff but i've been posting on the forum and i get no help on what kinds of things to change for full exhaust..

 

Are you sure you have the spark wires in the right firing order? I would check and make sure your custom end of the ends are right. If you didn't cut the insulantion correctly and/or have the wire core touching the terminal correctly it will cause a miss.

 

Yea, Check the Wires, Those custom sets arent for most weekend mechanics, I know.. I am a Mechanic and those were a Bitc*!!

 

M1tcs, put back the emission parts that help reduce the nocive gasses fuel combustuion produces, cat and air sistem in your case, it will run perfectly without coustom chip.

 

You don't need a custom chip just because you changed the exhaust and ripped out the emissions. I've been burning chips for quite some time and never needed to change anything to accomodate for that.
I'm SD. No cats, no AIR, no charcoal purge, full 3" duals, and headers. No changes and the car runs great.
I would concentrate more on the wires, ig module, and possibly the O2 sensor. You didn't drop the sensor on the ground did you?

 

What would not having an O2 sensor plugged in at all effect?

 

Closed loop fueling.