Goodwin header & midpipe= Check Engine light

[vetracr]

I recently installed a Goodwin header and mid pipe on my 09 NC sport. Since the installation I have been getting a P0171 (engine running lean) code when starting the car after it has been sitting overnight. When I installed the header I replaced both O2 sensors with new Mazda pieces. Both of the original O2 sensors were seized in the old cat (Don't ask). Additionally I'm using the Goodwin cable extensions on both O2 sensors. I also have a DIY cold air intake but the CEL problem did not show up until I replaced the header. My scan gauge confirmed the lean AFR (>15:1) condition prior to the code being set. Once the cars warms up it seems to run fine.

Thinking there was a leak I rechecked and tightened the air intake clamps. I then checked and retightened the header bolts and the header to mid pipe connection. There is no leak in the inlet effecting the MAF sensor and I'm sure there is no leak upstream of the O2 sensors in the header. I can't think the problem is related to other parts as the car only has 940 miles on it. It hasn't even been broken in yet.

The question is then why am I getting lean condition at start up? If I had a physical leak I would expect the problem to be there all the time. Is it possible there is a cable extension problem? I was surprised to find the rear cable extension was way longer than needed and the front cable extension is too short. I put insulated tape on it but it still runs near the header.

All ideas welcome TIA.

Larry

[Brian]

Could be extension cable...could be that one of the new sensors was damaged on install or otherwise not installed right...or is simply out of spec (ALL THE SENSORS ARE DIFFERENT....NO TWO ARE ALIKE). My first guess is that first sensor is not getting up to temperature fast enough which brings me back to the cables. I would check continuity on the cables with a multimeter first....paying close attention to make sure that two of the leads are not mixed up.

[vetracr]

Could be extension cable...could be that one of the new sensors was damaged on install or otherwise not installed right...or is simply out of spec (ALL THE SENSORS ARE DIFFERENT....NO TWO ARE ALIKE). My first guess is that first sensor is not getting up to temperature fast enough which brings me back to the cables. I would check continuity on the cables with a multimeter first....paying close attention to make sure that two of the leads are not mixed up.

Brian,

I checked continuity on extension cable with a Multimeter. Low resistance on all pins. It doesn't appear to be an open circuit problem. I'm sure the cables are on correctly as they are color coded. Even I can't screw that up addressing the first sensor heat up issue. I turned on the ignition and waited thirty seconds before starting the car, more than enough time for the O2 sensor to warm up (assuming the PCM feeds the O2 sensor voltage with the ignition on. Mazda manual is not the best at describing functionality).

Larry

[Brian]

Yes, impossible to mix the plugs....they don't interchange. What I meant is that we had one prior instance where Racing Beat got two of the wires mixed in the plug.