Headers installed, now runs terrible under 3k
Headers installed, now runs terrible under 3k Hey guys, just put a set of speed engineering headers, TR55s (.050 gap) and solid MWC mounts on the TA.. the car now misfires, surges and nearly wants to die.
I did some looking and figured it must be a bad new plug, or I cracked one when sliding the headers in, so pulled them all and they looked fine, put the ones that were in it back in to rule them out completely.
Now I'm starting to wonder if it's something with the o2 sensors. The front ones I extended (soldered and heat shrinked) and the rears I just put back in like the factory y-pipe is. Once above 3,000 rpms, the car pulls very well, just below that it's horrible. SES light flashes, but I can't read the code due to not having a scanner and not being able to drive it to Advance/O'Reillys.
Any help is appreciated, thanks guys.
I did some looking and figured it must be a bad new plug, or I cracked one when sliding the headers in, so pulled them all and they looked fine, put the ones that were in it back in to rule them out completely.
Now I'm starting to wonder if it's something with the o2 sensors. The front ones I extended (soldered and heat shrinked) and the rears I just put back in like the factory y-pipe is. Once above 3,000 rpms, the car pulls very well, just below that it's horrible. SES light flashes, but I can't read the code due to not having a scanner and not being able to drive it to Advance/O'Reillys.
Any help is appreciated, thanks guys.
Just unplugged the rear o2s and got the no improvement.
Also I've noticed the first 1/2 mile or so of driving the car runs like normal even at lower rpms, then it'll just sputter out and misfire.
Also I've noticed the first 1/2 mile or so of driving the car runs like normal even at lower rpms, then it'll just sputter out and misfire.
Sounds like a fuel trim issue. Be sure you don't have any leaks and it might be wise to swap the O2 sensors to rule them out. At higher throttle you O2's will be hotter and provide a better reading if there's a small leak, and at wot your ecu doesn't use the O2's for fuel trim tuning. Likely runs well for that first 1/2 mile because it's still in open loop.
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Sounds like a fuel trim issue. Be sure you don't have any leaks and it might be wise to swap the O2 sensors to rule them out. At higher throttle you O2's will be hotter and provide a better reading if there's a small leak, and at wot your ecu doesn't use the O2's for fuel trim tuning. Likely runs well for that first 1/2 mile because it's still in open loop.
Leaks before the front o2s? Or where else would really effect it?
Thanks for your advice.
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Verdad Gallardo Before. It would have to be either pretty big, or very close to the O2 for it to be so noticable. It could be after the O2 but it'd have to be pretty close. If you have a leak at the collector, that might do it. It's probably making one side read leaner than it should and the ecu keeps trying to alter the fuel trims and is causing it to run poorly.
Pulling the rear O2s does nothing but adds codes. What
is the response to pulling the fronts, forcing it open
loop? Try that along with resetting the fuel trims (scan
tool, or disconnect battery) to see if false trimming is
your problem.
is the response to pulling the fronts, forcing it open
loop? Try that along with resetting the fuel trims (scan
tool, or disconnect battery) to see if false trimming is
your problem.
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P0300 is multiple misfire.
Couple things, flashing engine light means severe miss, don't drive it, it damage to cats from excessive fuel.
Your codes reveal 2 things.
1. Check the connections on your mass air meter. It's pulling a code for that. It's likely unplugged, or damaged.
2. You're getting a lean code. This means that you're sucking in fresh air before the o2 sensors. This will cause it to run pig rich. You have an exhaust leak (s)
Couple things, flashing engine light means severe miss, don't drive it, it damage to cats from excessive fuel.
Your codes reveal 2 things.
1. Check the connections on your mass air meter. It's pulling a code for that. It's likely unplugged, or damaged.
2. You're getting a lean code. This means that you're sucking in fresh air before the o2 sensors. This will cause it to run pig rich. You have an exhaust leak (s)
This ended up fixing the issue. I had the clamps sideways because it looks much cleaner, little did I realize that it pinchedthe side instead of the slots on the top and bottom. Car feels a bit doggy, but I'm blaming that on no tune and still having old plugs in it. Thanks all for your help.
