Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: Grumpy on November 28, 2008, 09:16:38 PM

Title: Stuttering Orvis!!!
Post by: Grumpy on November 28, 2008, 09:16:38 PM

Hey Guys,

Just been daft enough to add to my collection and purchased a 1999 4.0 litre XJ Orvis from fleabay...OK stop laughing :applaudit: .

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Post by: mikesknives on November 28, 2008, 10:01:57 PM

just get the bit out of a breakers it'll only be £20

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Post by: scrw on November 28, 2008, 10:04:37 PM

Service it and clean the TB and ICV first off.

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Post by: Jonny Jeep on November 30, 2008, 01:46:24 PM

The heater circuit in the upstream O2 sensor is failing. That means when the computer switches to using the sensor data, the sensor hasn't heated fully, and isn't supplying accurate data to the computer causing it to run rich. Once the engine has run for a short while longer the exhaust gases heat the sensor past the point where it starts supplying accurate data and the engine runs smoothly till the next cold start.

Pop the hood and go the the manifold side of the engine. The sensor is in the exhaust pipe just below where it bolts to the exhaust manifold. Follow the wire up to the rear of the inlet manifold where you will find the plug. Disconnect the plug. The computer will light the check engine light because the sensor is disconnected, but the engine will run smoothly with no stutter from cold starts. Plugging the sensor back in will cause the stutter to reappear.

Fitting a new upstream O2 sensor is the cure.

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Post by: Grumpy on December 01, 2008, 08:04:07 PM

Hi Guys,

Thanks for the replies. I have cleaned out the throttle body, idle control etc but didn't make any difference. Then I tried Jonny Jeep's sugestion,disconnected the up-stream O2 sensor and ran it from cold, no problems at all, even the "check engine light" stayed off after start up. Car ran nice and smooth through a 5 mile trip. So I now needs to buy an new sensor.

Thanks again - top tips.
Regards, Grumpy .