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Followup To
Question -
Recently i had a valve job done on it. They resurfaced the upper head as well. After getting everything back together, It ran. The engine light was still on, but i figured it was because i never reset it. About 800-1000 miles later I checked the codes and recieved "missing or bad o2, missing or bad MAF". I reset the ecu (A2) and drove it around, then cheked for faults in A2. I found none. When I took it in for smog I failed Hydrocarbon(max=85 meas=102) at 15mph, but passed at 25mph. I've read that O2 sensors can go bad and be undetected by the ecu. It has seemed to lose power on acceleration, but i thought maybe 'cause it had 140k mi on the engine. Should i try to clean the MAF and O2 sensors? How can I be sure they're in working order? What else should I look for?
Answer -
Hello,
For this type is a bit hard, because after 97 model via Volvo System Tester it is easy, (however, if you can find a Volvo System Tester, you can test again the Oxygen sensor, its values goes 0-1 value, if it is constant it means the oxygen sensor has problem). But, I can say that your oxygen sensor seems problem according to your tellings, I recommend you to replace it with new one.
Regards..
The 93 850 GLT comes with an on board diagnostic system. If I'm not getting faults at that point, is there actualy an electrical fault (open/closed circuit)at the O2?
AnswerHello again,
I know, 93 850 has OBD, but it is primitive a bit, because as you know OBDII is more complicated, so with OBDII it is easier, because of this reason I wrote that.
And, the other one, the oxygen sensor case is generally hard for OBD, because sometimes you can not find any code, but it does not mean the oxygen sensor has no faulty, especially it can be said for the cases that if there is smoke from exhaust (even there is no code), it means oxygen sensor is defective.
Regards...
