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Will I need new 02 sensors ????

  • Thread starter Thread starter just4bob50
  • Start date Start date Sep 30, 2006

just4bob50

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Apr 2, 2005
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#1
  • Sep 30, 2006
  • #1
Weel the othe night I popped both my head gaskets beating on the car. It looks as though the heads lifted again because the gaskets where blown out from the water jackets to the fire ring with no burn marks on the ring. I had ARP head bolts instead of head studs and it cost me. ( 12psi of boost @ 5500 ) Any how I had to limp the car home as I was only a few miles away. The car never over heated but was blowing major amounts of white smoke. I was wondering if the fact that I drove the car for a few miles in that condition if it would have done anything to the 02 sensors. The sensors are less than 2 years old and I didnt want ot have to replace them also.
 

jrichker

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Sep 30, 2006
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Dump the codes & look for codes 41 & 91. If you get them, replace the O2 sensors.

Measuring the O2 sensor voltage at the computer will give you a good idea of how well they are working. You'll have to pull the passenger side kick panel off to gain access to the computer connector. Remove the plastic wiring cover to get to the back side of the wiring. Use a safety pin or paper clip to probe the connections from the rear. The computer pins are 29 (LH O2 with a dark green/pink wire) and 43 (RH O2 with a dark blue/pink wire). Use the ground next to the computer to ground the voltmeter.

The following is a Quote from Charles O. Probst, Ford fuel Injection & Electronic Engine control:
"When the mixture is lean, the exhaust gas has oxygen, about the same amount as the ambient air. So the sensor will generate less than 400 Millivolts. Remember lean = less voltage.

When the mixture is rich, there's less oxygen in the exhaust than in the ambient air , so voltage is generated between the two sides of the tip. The voltage is greater than 600 millivolts. Remember rich = more voltage.

Here's a tip: the newer the sensor, the more the voltage changes, swinging from as low as 0.1 volt to as much as 0.9 volt. As an oxygen sensor ages, the voltage changes get smaller and slower - the voltage change lags behind the change in exhaust gas oxygen.

Because the oxygen sensor generates its own voltage, never apply voltage and never measure resistance of the sensor circuit. To measure voltage signals, use an analog voltmeter with a high input impedance, at least 10 megohms. Remember, a digital voltmeter will average a changing voltage." End Quote
 

just4bob50

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  • Sep 30, 2006
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Thanls Jrichker... Thats just what i needed to know.
 
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