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P0420

  • Denkramer
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14 Jan 2020 22:35 #36628 by Denkramer
P0420 was created by Denkramer
I have a 2013 Chevy Equinox 2.4L engine. Had a P0420 DTC. Replaced the cat, also found when I started to replace the cat the upstream O2 sensor thimble cover had melted or broke apart damaging the cat. I replaced the cat and upstream O2 sensor. Also found that the PCV system has been leaking for some time into the air box. I had to replace the valve cover because the PCV is built into the valve cover. I hooked up my scanner before and after I replace the PCV system and my short term fuel trim at idle would be less then 10% along with LTFT. Under light loads would jump up to +34% and lTFT would stay under 10%. STFT will not stay constant it goes negative then single digits and back up to +34% STFT. LTFT stays under 10% all the time. I also replaced spark plugs they looked old and worn. No coolant or oil deposits were on the spark plugs. There was a small miss before I replace the plugs and PCV system but that is not there now. I did clean out the throttle valve because you could see the oil residue in the body and in the intake manifold. Were else should I look at? The car seems to have plenty of power. I don't think it is a fuel delivery problem but what about a leaking injector? I am concerned about the STFT numbers they are all over the place pikes and valleys. Has anyone seen this?

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14 Jan 2020 23:50 #36630 by scannerjohn
Replied by scannerjohn on topic P0420
fuel pump issue... check fuel pressure readings.

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