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until yesterday i never really gave the oxygen sensor its due. oh sure, keeping a good one installed is a given but whether a 240 car would NOT run right at all should the wrong one be installed had not entered my mind.
long story short a 92 240 wagon came my way over the weekend that simply refused to run for more than 60 seconds. the owner had given up and sold it:
parts i found to be new or somewhat recent were:
a FPR, fuel filter, wires, plugs, cap , rotor, NEW AMM, crank sensor, oxygen sensor
thus it came to me out of frustration and hopelessness.
the first step was to set timing to TDC and see if this was ok.
it was not as the cam sprocket was advanced 2 teeth from where it ought to be.
though a normal routine procedure in a diagnosis the corrected timing had little effect other than making starting easier.
the car still ran for seconds and then slowly died over the following 120 seconds.
the next step was measure the voltage at the o2 sensor signal wire for at least 60 seconds. the results were:
starting point .543 volts NEVER LOWER and NO oscillation
over the 60 seconds the measurement rose to 1.08 volts whereupon the car began to shake and stall out.
the o2 sensor installed was a 4 wire NTK 29416 with the ground wire looped back on itself by the installer.
if you say ah ha now you'd be right.
after removing this sensor and splicing in a bosch 13913 all running issues disappeared as if by magic.
the moral and cautionary point of this sad story is never presume the word 'universal' on the side of an 02 sensor box automatically means it will work in your world. and the addendum is...........ALWAYS double check exactly WHAT your local garage mechanic has installed in your car by looking at the box it came in or verify the bill to make sure it really fits. Sometimes it doesn't with costly and disastrous consequences
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