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O2 sensor failure causing engine to shutoff?

Jalves619

NAXJA Forum User
Location
Flagstaff, Az
Just pick up a 1995 4.0 Automatic NP231 Cherokee. On it's maiden voyage from Flagstaff to Tucson it began to cut out and then lost power altogether. CEL lights up and flashes a code for an O2 sensor failure. I open the hood to find that due to some poor planning, that the oxygen sensor had occupied the same space as the front driveshaft. The driveshaft got a little carried away and beat the poor peaceful oxygen sensor into submission. Now there are suits being filed claiming "Driveshaft Brutality" and "Use of excessive torque" all while my new to me Cherokee is sitting on the side of the freeway. So here the real question, Will a catastrophic O2 sensor failure cause an engine to shutoff and then subsequently not start?


Cliff Notes
-1995 OBD1 4.0 Auto NP231
-Cherokee dies on the freeway.
-CEL code for Oxy Sensor
-Oxygen Sensor is broken in half.
-Car will crank, but won't start.
Cause and effect? or do I need to look elsewhere?
 
A few threads I've read mention a fuse that might cause these symptoms. So to take my question a step further if this is the cause, and I replace the fuse and disconnect the O2 sensor, will the ECU switch to a limp home mode so I can get the car on to a trailer or off the interstate?
 
normally an O2 sensor will Not cause a no start. It may run like chit, but it will run. I have never seen an O2 sensor cause a no start on any car. I think you need to look a little deeper.
 
The shorted wires on the O2 sensor may have blew a fuse that feeds the 5V reference voltage for the TPS and CPS.
Several years ago the Cam Position Sensor inside the distributor shorted to the curved trigger attached to the distributor base plate; this caused my engine to shut down immediately.
 
I had a similar problem, when my O2 sensor's wires melted.

If the heater element wires have touched you will of blown the 30A Engine control fuse.

Unplug the o2 sensor, replace that fuse, drive home and fit a new o2. Disconect the battery over night and bobs your uncle :)
 
The shorted wires on the O2 sensor may have blew a fuse that feeds the 5V reference voltage for the TPS and CPS.
Several years ago the Cam Position Sensor inside the distributor shorted to the curved trigger attached to the distributor base plate; this caused my engine to shut down immediately.
 
I can see if the 5 volt ref being compromised could cause no start issues. But that would be easy to track down, see if fuse is blown, if so unplug all sensors that use the 5 volt ref. Replace fuse, start plugging in one at a time & see what one pops the fuse & you know what circuit to start chasing down.
 
A bad O2 sensor will cause the engine to shut down and not start if the engine is hot. I had that happen to me before. Let the engine cool and it will start right back up. The O2 sensor is not read when the engine is cold. If the sensor is not connected,....well,....I do not know the answer to that. Mine was always connected but it was bad. I could drive about 15 minutes from home, (Miami summer heat) let the XJ sit engine off 30 + minutes and drive back home.

Get that O2 sensor replaced if you want to use the XJ. Remove the front drive shaft if you have to. I will hurt nothing to drive without it.
 
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