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Old 02-26-2019, 04:06 PM
Witsend Witsend is offline
Join Date: Nov 2012
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Sounds like engine might not be going in closed loop operation for some reason or other . Engine temp too cold ?, Exhaust may not be getting hot enough for non heated O2 sensors to operate correctly ( if the heat generating cats are now missing)? , Major vacuum leak? , Low fuel pressure. Maybe if O2 sensors were screwed into bungs while the bypass pipes were getting Arc Welded on near them they got arc current damaged? If they are not exhaust manifold mounted , try wrapping the exhaust pipes to the O2 sensors and a little past them with header tape to retain more heat inside. Even if you get the front O2s to work and fuel trims down, the light will likely come back on for the downstream O2s , Cat efficiency, or insufficient EGR flow
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