HELP! Car running terribly after header install
HELP! Car running terribly after header install Got pacesetter LTs installed with pacesetter ory and magnaflow cat back about a week ago. Car is a 2001 Camaro SS. At the time I only installed 1 O2 sensor extension cause the other hadn't come in yet. Car drove fine, felt a tad sluggish on the low end which is normal after headers with no tune as far as I know.
Fast forward to today, car is at the shop getting pinion seal in rear end done. In addition the missing O2 extension was installed. After work is completed my mechanic calls saying the car is driving like total **** and misfiring? So yeah...
I don't understand how it ran better with a missing O2 than with both?
Edit: I'm reading a lot of threads with people with the same issue but all of them die out without the OP ever solving his problem (or he just never updated the thread saying he fixed it and what the issue was). However the most common problems seems to be a cracked spark plug or burnt wire. Is this likely my issue or would the car have ran like crap from the beginning if that was the case? Whats weird is that it just started running bad today. Another possibility is a stripped O2? Also maybe a bad IAT sensor which is not header related but maybe coincidence? Is there any way to tell what exactly the problem is before I start randomly replacing parts?
Fast forward to today, car is at the shop getting pinion seal in rear end done. In addition the missing O2 extension was installed. After work is completed my mechanic calls saying the car is driving like total **** and misfiring? So yeah...
I don't understand how it ran better with a missing O2 than with both?
Edit: I'm reading a lot of threads with people with the same issue but all of them die out without the OP ever solving his problem (or he just never updated the thread saying he fixed it and what the issue was). However the most common problems seems to be a cracked spark plug or burnt wire. Is this likely my issue or would the car have ran like crap from the beginning if that was the case? Whats weird is that it just started running bad today. Another possibility is a stripped O2? Also maybe a bad IAT sensor which is not header related but maybe coincidence? Is there any way to tell what exactly the problem is before I start randomly replacing parts?
Last edited by badformulaLS1; Oct 6, 2013 at 10:32 AM.
im not sure but i think the front o2 sensors have a different connector then the rear o2's so you cant plug them in wrong. Its possible a plug wire got to close to the headers and melted causing a misfire. Ive had headers on my car with stock tune and it ran fine with no bog or power loss. If the shop its at is competent enough to put in a pinion seal they should be able to figure out why its misfiring.
I also forgot to add new plug wires were installed at the same time also. The plug wire melting might be a possibility. If so I guess I need a whole new set right? How do I prevent this from happening?
Running without the oxygen sensor the car will run in open loop (it runs off of known tables in the computer rather than taking input from o2's) so it ran okay, then you plugged it in so it's running in closed loop now. The best thing to do would be to use a scanner to get some live data and see if the oxygen sensors are switching properly, and indeed showing a reading. If you have exhaust leaks ahead of, or directly behind the oxygen sensors it could definitely contribute to running poorly, maybe a fouled plug, etc
Thanks for the responses. Well I got it scanned and its giving a code for coolant temp sensor. Is that O2 related? I don't remember the exact code number. Anyone know what could be causing it? Maybe the sensor broke during install? It's getting **** mpg too. It's gradually gotten worse from the random surging that started a few days ago prior to the 2nd O2 being put on and its been almost 2 weeks since the headers were done. I don't think the O2 could've gotten any moisture in it.
Last edited by badformulaLS1; Oct 5, 2013 at 01:54 PM.
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Alright thanks guys, I haven't had a chance to look at it I just left it at the shop today. Monday I'll check it out. Hopefully it's just broken or unplugged because I'm not quite ready financially for a tune if the car is just acting up. I thought these cars were supposed to be fine without a tune after headers/ory.
google kool sox it slips over the wires near the plug so this will not happen
the reason this happens with a bad or unplugged Coolant temp sensor is the PCM uses the coolant temp of the car as one of its inputs for calculating injector pulse width, and Coolant temp is one of the higher priority inputs. With a broken or unplugged sensor, the PCM defaults to -40 degrees reading, which will increase the pulse width and just dump a ton of fuel. Just some knowledge if you wanted to know. Glad you got it fixed.
the reason this happens with a bad or unplugged Coolant temp sensor is the PCM uses the coolant temp of the car as one of its inputs for calculating injector pulse width, and Coolant temp is one of the higher priority inputs. With a broken or unplugged sensor, the PCM defaults to -40 degrees reading, which will increase the pulse width and just dump a ton of fuel. Just some knowledge if you wanted to know. Glad you got it fixed.