O2 sensors not cycling at all no closed loop
11-06-2016, 05:03 PM
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O2 sensors not cycling at all no closed loop Hi all,
Running a 2002 stock 5.3 in a K5 blazer. Pulled everything from running driving donor truck. Swap started great but went downhill fast. Keeps throwing CEL on for no o2 activity and fuel trim is zero. Indeed scan tool log graph shows all 4 sensors at nearly constant 0.45. As opposed to the 03 suburban parked next to it where the o2 sensors cycle almost immediately after starting, so I know the tool works right.
Running 3 wire Camaro temp sender and gauge and scan tool show water temp at 185. If you unplug temp,sensor car almost dies so I know it is hooked up. One of the error codes said insufficient temperature to enter closed loop.
Started swap with factory harness but it had intermittent issues with o2 sensor readings (jiggling harness would make it come and go) so I bought a brand new harness at great expense, now zilch.
All sensors brand new Bosch installed with swap. Tracing wiring from plug to PCM with ohmmeter seems fine which it should be for a new harness.
PCM was modded by lt1swap and the thing ran fine in closed look for about a week then just stopped running right.
Any ideas?
Running a 2002 stock 5.3 in a K5 blazer. Pulled everything from running driving donor truck. Swap started great but went downhill fast. Keeps throwing CEL on for no o2 activity and fuel trim is zero. Indeed scan tool log graph shows all 4 sensors at nearly constant 0.45. As opposed to the 03 suburban parked next to it where the o2 sensors cycle almost immediately after starting, so I know the tool works right.
Running 3 wire Camaro temp sender and gauge and scan tool show water temp at 185. If you unplug temp,sensor car almost dies so I know it is hooked up. One of the error codes said insufficient temperature to enter closed loop.
Started swap with factory harness but it had intermittent issues with o2 sensor readings (jiggling harness would make it come and go) so I bought a brand new harness at great expense, now zilch.
All sensors brand new Bosch installed with swap. Tracing wiring from plug to PCM with ohmmeter seems fine which it should be for a new harness.
PCM was modded by lt1swap and the thing ran fine in closed look for about a week then just stopped running right.
Any ideas?
Last edited by Smallblockeight; 11-06-2016 at 05:09 PM.
11-07-2016, 05:10 PM
#3
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Seems like harness was built for case ground sensors but I have isolated ground. Confirmed my friend who is electrical engineer using wiring diagrams and ohm meter. Still arguing with harness vendor tho...